legalize marijuana research paper

• Research article
• Open access
• Published: 04 February 2020

Marijuana legalization and historical trends in marijuana use among US residents aged 12–25: results from the 1979–2016 National Survey on drug use and health

• Xinguang Chen 1 ,
• Xiangfan Chen 2 &
• Hong Yan 2  

BMC Public Health volume  20 , Article number:  156 ( 2020 ) Cite this article

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Marijuana is the most commonly used illicit drug in the United States. More and more states legalized medical and recreational marijuana use. Adolescents and emerging adults are at high risk for marijuana use. This ecological study aims to examine historical trends in marijuana use among youth along with marijuana legalization.

Data ( n  = 749,152) were from the 31-wave National Survey on Drug Use and Health (NSDUH), 1979–2016. Current marijuana use, if use marijuana in the past 30 days, was used as outcome variable. Age was measured as the chronological age self-reported by the participants, period was the year when the survey was conducted, and cohort was estimated as period subtracted age. Rate of current marijuana use was decomposed into independent age, period and cohort effects using the hierarchical age-period-cohort (HAPC) model.

After controlling for age, cohort and other covariates, the estimated period effect indicated declines in marijuana use in 1979–1992 and 2001–2006, and increases in 1992–2001 and 2006–2016. The period effect was positively and significantly associated with the proportion of people covered by Medical Marijuana Laws (MML) (correlation coefficients: 0.89 for total sample, 0.81 for males and 0.93 for females, all three p values < 0.01), but was not significantly associated with the Recreational Marijuana Laws (RML). The estimated cohort effect showed a historical decline in marijuana use in those who were born in 1954–1972, a sudden increase in 1972–1984, followed by a decline in 1984–2003.

The model derived trends in marijuana use were coincident with the laws and regulations on marijuana and other drugs in the United States since the 1950s. With more states legalizing marijuana use in the United States, emphasizing responsible use would be essential to protect youth from using marijuana.

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Introduction

Marijuana use and laws in the united states.

Marijuana is one of the most commonly used drugs in the United States (US) [ 1 ]. In 2015, 8.3% of the US population aged 12 years and older used marijuana in the past month; 16.4% of adolescents aged 12–17 years used in lifetime and 7.0% used in the past month [ 2 ]. The effects of marijuana on a person’s health are mixed. Despite potential benefits (e.g., relieve pain) [ 3 ], using marijuana is associated with a number of adverse effects, particularly among adolescents. Typical adverse effects include impaired short-term memory, cognitive impairment, diminished life satisfaction, and increased risk of using other substances [ 4 ].

Since 1937 when the Marijuana Tax Act was issued, a series of federal laws have been subsequently enacted to regulate marijuana use, including the Boggs Act (1952), Narcotics Control Act (1956), Controlled Substance Act (1970), and Anti-Drug Abuse Act (1986) [ 5 , 6 ]. These laws regulated the sale, possession, use, and cultivation of marijuana [ 6 ]. For example, the Boggs Act increased the punishment of marijuana possession, and the Controlled Substance Act categorized the marijuana into the Schedule I Drugs which have a high potential for abuse, no medical use, and not safe to use without medical supervision [ 5 , 6 ]. These federal laws may have contributed to changes in the historical trend of marijuana use among youth.

Movements to decriminalize and legalize marijuana use

Starting in the late 1960s, marijuana decriminalization became a movement, advocating reformation of federal laws regulating marijuana [ 7 ]. As a result, 11 US states had taken measures to decriminalize marijuana use by reducing the penalty of possession of small amount of marijuana [ 7 ].

The legalization of marijuana started in 1993 when Surgeon General Elder proposed to study marijuana legalization [ 8 ]. California was the first state that passed Medical Marijuana Laws (MML) in 1996 [ 9 ]. After California, more and more states established laws permitting marijuana use for medical and/or recreational purposes. To date, 33 states and the District of Columbia have established MML, including 11 states with recreational marijuana laws (RML) [ 9 ]. Compared with the legalization of marijuana use in the European countries which were more divided that many of them have medical marijuana registered as a treatment option with few having legalized recreational use [ 10 , 11 , 12 , 13 ], the legalization of marijuana in the US were more mixed with 11 states legalized medical and recreational use consecutively, such as California, Nevada, Washington, etc. These state laws may alter people’s attitudes and behaviors, finally may lead to the increased risk of marijuana use, particularly among young people [ 13 ]. Reported studies indicate that state marijuana laws were associated with increases in acceptance of and accessibility to marijuana, declines in perceived harm, and formation of new norms supporting marijuana use [ 14 ].

Marijuana harm to adolescents and young adults

Adolescents and young adults constitute a large proportion of the US population. Data from the US Census Bureau indicate that approximately 60 million of the US population are in the 12–25 years age range [ 15 ]. These people are vulnerable to drugs, including marijuana [ 16 ]. Marijuana is more prevalent among people in this age range than in other ages [ 17 ]. One well-known factor for explaining the marijuana use among people in this age range is the theory of imbalanced cognitive and physical development [ 4 ]. The delayed brain development of youth reduces their capability to cognitively process social, emotional and incentive events against risk behaviors, such as marijuana use [ 18 ]. Understanding the impact of marijuana laws on marijuana use among this population with a historical perspective is of great legal, social and public health significance.

Inconsistent results regarding the impact of marijuana laws on marijuana use

A number of studies have examined the impact of marijuana laws on marijuana use across the world, but reported inconsistent results [ 13 ]. Some studies reported no association between marijuana laws and marijuana use [ 14 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ], some reported a protective effect of the laws against marijuana use [ 24 , 26 ], some reported mixed effects [ 27 , 28 ], while some others reported a risk effect that marijuana laws increased marijuana use [ 29 , 30 ]. Despite much information, our review of these reported studies revealed several limitations. First of all, these studies often targeted a short time span, ignoring the long period trend before marijuana legalization. Despite the fact that marijuana laws enact in a specific year, the process of legalization often lasts for several years. Individuals may have already changed their attitudes and behaviors before the year when the law is enacted. Therefore, it may not be valid when comparing marijuana use before and after the year at a single time point when the law is enacted and ignoring the secular historical trend [ 19 , 30 , 31 ]. Second, many studies adapted the difference-in-difference analytical approach designated for analyzing randomized controlled trials. No US state is randomized to legalize the marijuana laws, and no state can be established as controls. Thus, the impact of laws cannot be efficiently detected using this approach. Third, since marijuana legalization is a public process, and the information of marijuana legalization in one state can be easily spread to states without the marijuana laws. The information diffusion cannot be ruled out, reducing the validity of the non-marijuana law states as the controls to compare the between-state differences [ 31 ].

Alternatively, evidence derived based on a historical perspective may provide new information regarding the impact of laws and regulations on marijuana use, including state marijuana laws in the past two decades. Marijuana users may stop using to comply with the laws/regulations, while non-marijuana users may start to use if marijuana is legal. Data from several studies with national data since 1996 demonstrate that attitudes, beliefs, perceptions, and use of marijuana among people in the US were associated with state marijuana laws [ 29 , 32 ].

Age-period-cohort modeling: looking into the past with recent data

To investigate historical trends over a long period, including the time period with no data, we can use the classic age-period-cohort modeling (APC) approach. The APC model can successfully discompose the rate or prevalence of marijuana use into independent age, period and cohort effects [ 33 , 34 ]. Age effect refers to the risk associated with the aging process, including the biological and social accumulation process. Period effect is risk associated with the external environmental events in specific years that exert effect on all age groups, representing the unbiased historical trend of marijuana use which controlling for the influences from age and birth cohort. Cohort effect refers to the risk associated with the specific year of birth. A typical example is that people born in 2011 in Fukushima, Japan may have greater risk of cancer due to the nuclear disaster [ 35 ], so a person aged 80 in 2091 contains the information of cancer risk in 2011 when he/she was born. Similarly, a participant aged 25 in 1979 contains information on the risk of marijuana use 25 years ago in 1954 when that person was born. With this method, we can describe historical trends of marijuana use using information stored by participants in older ages [ 33 ]. The estimated period and cohort effects can be used to present the unbiased historical trend of specific topics, including marijuana use [ 34 , 36 , 37 , 38 ]. Furthermore, the newly established hierarchical APC (HAPC) modeling is capable of analyzing individual-level data to provide more precise measures of historical trends [ 33 ]. The HAPC model has been used in various fields, including social and behavioral science, and public health [ 39 , 40 ].

Several studies have investigated marijuana use with APC modeling method [ 17 , 41 , 42 ]. However, these studies covered only a small portion of the decades with state marijuana legalization [ 17 , 42 ]. For example, the study conducted by Miech and colleagues only covered periods from 1985 to 2009 [ 17 ]. Among these studies, one focused on a longer state marijuana legalization period, but did not provide detailed information regarding the impact of marijuana laws because the survey was every 5 years and researchers used a large 5-year age group which leads to a wide 10-year birth cohort. The averaging of the cohort effects in 10 years could reduce the capability of detecting sensitive changes of marijuana use corresponding to the historical events [ 41 ].

Purpose of the study

In this study, we examined the historical trends in marijuana use among youth using HAPC modeling to obtain the period and cohort effects. These two effects provide unbiased and independent information to characterize historical trends in marijuana use after controlling for age and other covariates. We conceptually linked the model-derived time trends to both federal and state laws/regulations regarding marijuana and other drug use in 1954–2016. The ultimate goal is to provide evidence informing federal and state legislation and public health decision-making to promote responsible marijuana use and to protect young people from marijuana use-related adverse consequences.

Materials and methods

Data sources and study population.

Data were derived from 31 waves of National Survey on Drug Use and Health (NSDUH), 1979–2016. NSDUH is a multi-year cross-sectional survey program sponsored by the Substance Abuse and Mental Health Services Administration. The survey was conducted every 3 years before 1990, and annually thereafter. The aim is to provide data on the use of tobacco, alcohol, illicit drug and mental health among the US population.

Survey participants were noninstitutionalized US civilians 12 years of age and older. Participants were recruited by NSDUH using a multi-stage clustered random sampling method. Several changes were made to the NSDUH after its establishment [ 43 ]. First, the name of the survey was changed from the National Household Survey on Drug Abuse (NHSDA) to NSDUH in 2002. Second, starting in 2002, adolescent participants receive $30 as incentives to improve the response rate. Third, survey mode was changed from personal interviews with self-enumerated answer sheets (before 1999) to the computer-assisted person interviews (CAPI) and audio computer-assisted self-interviews (ACASI) (since 1999). These changes may confound the historical trends [ 43 ], thus we used two dummy variables as covariates, one for the survey mode change in 1999 and another for the survey method change in 2002 to control for potential confounding effect.

Data acquisition

Data were downloaded from the designated website ( https://nsduhweb.rti.org/respweb/homepage.cfm ). A database was used to store and merge the data by year for analysis. Among all participants, data for those aged 12–25 years ( n  = 749,152) were included. We excluded participants aged 26 and older because the public data did not provide information on single or two-year age that was needed for HAPC modeling (details see statistical analysis section). We obtained approval from the Institutional Review Board at the University of Florida to conduct this study.

Variables and measurements

Current marijuana use: the dependent variable. Participants were defined as current marijuana users if they reported marijuana use within the past 30 days. We used the variable harmonization method to create a comparable measure across 31-wave NSDUH data [ 44 ]. Slightly different questions were used in NSDUH. In 1979–1993, participants were asked: “When was the most recent time that you used marijuana or hash?” Starting in 1994, the question was changed to “How long has it been since you last used marijuana or hashish?” To harmonize the marijuana use variable, participants were coded as current marijuana users if their response to the question indicated the last time to use marijuana was within past 30 days.

Chronological age, time period and birth cohort were the predictors. (1) Chronological age in years was measured with participants’ age at the survey. APC modeling requires the same age measure for all participants [ 33 ]. Since no data by single-year age were available for participants older than 21, we grouped all participants into two-year age groups. A total of 7 age groups, 12–13, ..., 24–25 were used. (2) Time period was measured with the year when the survey was conducted, including 1979, 1982, 1985, 1988, 1990, 1991... 2016. (3). Birth cohort was the year of birth, and it was measured by subtracting age from the survey year.

The proportion of people covered by MML: This variable was created by dividing the population in all states with MML over the total US population. The proportion was computed by year from 1996 when California first passed the MML to 2016 when a total of 29 states legalized medical marijuana use. The estimated proportion ranged from 12% in 1996 to 61% in 2016. The proportion of people covered by RML: This variable was derived by dividing the population in all states with RML with the total US population. The estimated proportion ranged from 4% in 2012 to 21% in 2016. These two variables were used to quantitatively assess the relationships between marijuana laws and changes in the risk of marijuana use.

Covariates: Demographic variables gender (male/female) and race/ethnicity (White, Black, Hispanic and others) were used to describe the study sample.

Statistical analysis

We estimated the prevalence of current marijuana use by year using the survey estimation method, considering the complex multi-stage cluster random sampling design and unequal probability. A prevalence rate is not a simple indicator, but consisting of the impact of chronological age, time period and birth cohort, named as age, period and cohort effects, respectively. Thus, it is biased if a prevalence rate is directly used to depict the historical trend. HAPC modeling is an epidemiological method capable of decomposing prevalence rate into mutually independent age, period and cohort effects with individual-level data, while the estimated period and cohort effects provide an unbiased measure of historical trend controlling for the effects of age and other covariates. In this study, we analyzed the data using the two-level HAPC cross-classified random-effects model (CCREM) [ 36 ]:

Where M ijk represents the rate of marijuana use for participants in age group i (12–13, 14,15...), period j (1979, 1982,...) and birth cohort k (1954–55, 1956–57...); parameter α i (age effect) was modeled as the fixed effect; and parameters β j (period effect) and γ k (cohort effect) were modeled as random effects; and β m was used to control m covariates, including the two dummy variables assessing changes made to the NSDUH in 1999 and 2002, respectively.

The HAPC modeling analysis was executed using the PROC GLIMMIX. Sample weights were included to obtain results representing the total US population aged 12–25. A ridge-stabilized Newton-Raphson algorithm was used for parameter estimation. Modeling analysis was conducted for the overall sample, stratified by gender. The estimated age effect α i , period β j and cohort γ k (i.e., the log-linear regression coefficients) were directly plotted to visualize the pattern of change.

To gain insight into the relationship between legal events and regulations at the national level, we listed these events/regulations along with the estimated time trends in the risk of marijuana from HAPC modeling. To provide a quantitative measure, we associated the estimated period effect with the proportions of US population living with MML and RML using Pearson correlation. All statistical analyses for this study were conducted using the software SAS, version 9.4 (SAS Institute Inc., Cary, NC).

Sample characteristics

Data for a total of 749,152 participants (12–25 years old) from all 31-wave NSDUH covering a 38-year period were analyzed. Among the total sample (Table  1 ), 48.96% were male and 58.78% were White, 14.84% Black, and 18.40% Hispanic.

Prevalence rate of current marijuana use

As shown in Fig.  1 , the estimated prevalence rates of current marijuana use from 1979 to 2016 show a “V” shaped pattern. The rate was 27.57% in 1979, it declined to 8.02% in 1992, followed by a gradual increase to 14.70% by 2016. The pattern was the same for both male and female with males more likely to use than females during the whole period.

Prevalence rate (%) of current marijuana use among US residents 12 to 25 years of age during 1979–2016, overall and stratified by gender. Derived from data from the 1979–2016 National Survey on Drug Use and Health (NSDUH)

HAPC modeling and results

Estimated age effects α i from the CCREM [ 1 ] for current marijuana use are presented in Fig.  2 . The risk by age shows a 2-phase pattern –a rapid increase phase from ages 12 to 19, followed by a gradually declining phase. The pattern was persistent for the overall sample and for both male and female subsamples.

Age effect for the risk of current marijuana use, overall and stratified by male and female, estimated with hierarchical age-period-cohort modeling method with 31 waves of NSDUH data during 1979–2016. Age effect α i were log-linear regression coefficients estimated using CCREM (1), see text for more details

The estimated period effects β j from the CCREM [ 1 ] are presented in Fig.  3 . The period effect reflects the risk of current marijuana use due to significant events occurring over the period, particularly federal and state laws and regulations. After controlling for the impacts of age, cohort and other covariates, the estimated period effect indicates that the risk of current marijuana use had two declining trends (1979–1992 and 2001–2006), and two increasing trends (1992–2001 and 2006–2016). Epidemiologically, the time trends characterized by the estimated period effects in Fig. 3 are more valid than the prevalence rates presented in Fig. 1 because the former was adjusted for confounders while the later was not.

Period effect for the risk of marijuana use for US adolescents and young adults, overall and by male/female estimated with hierarchical age-period-cohort modeling method and its correlation with the proportion of US population covered by Medical Marijuana Laws and Recreational Marijuana Laws. Period effect β j were log-linear regression coefficients estimated using CCREM (1), see text for more details

Correlation of the period effect with proportions of the population covered by marijuana laws: The Pearson correlation coefficient of the period effect with the proportions of US population covered by MML during 1996–2016 was 0.89 for the total sample, 0.81 for male and 0.93 for female, respectively ( p  < 0.01 for all). The correlation between period effect and proportion of US population covered by RML was 0.64 for the total sample, 0.59 for male and 0.49 for female ( p  > 0.05 for all).

Likewise, the estimated cohort effects γ k from the CCREM [ 1 ] are presented in Fig.  4 . The cohort effect reflects changes in the risk of current marijuana use over the period indicated by the year of birth of the survey participants after the impacts of age, period and other covariates are adjusted. Results in the figure show three distinctive cohorts with different risk patterns of current marijuana use during 1954–2003: (1) the Historical Declining Cohort (HDC): those born in 1954–1972, and characterized by a gradual and linear declining trend with some fluctuations; (2) the Sudden Increase Cohort (SIC): those born from 1972 to 1984, characterized with a rapid almost linear increasing trend; and (3) the Contemporary Declining Cohort (CDC): those born during 1984 and 2003, and characterized with a progressive declining over time. The detailed results of HAPC modeling analysis were also shown in Additional file 1 : Table S1.

Cohort effect for the risk of marijuana use among US adolescents and young adults born during 1954–2003, overall and by male/female, estimated with hierarchical age-period-cohort modeling method. Cohort effect γ k were log-linear regression coefficients estimated using CCREM (1), see text for more details

This study provides new data regarding the risk of marijuana use in youth in the US during 1954–2016. This is a period in the US history with substantial increases and declines in drug use, including marijuana; accompanied with many ups and downs in legal actions against drug use since the 1970s and progressive marijuana legalization at the state level from the later 1990s till today (see Additional file 1 : Table S2). Findings of the study indicate four-phase period effect and three-phase cohort effect, corresponding to various historical events of marijuana laws, regulations and social movements.

Coincident relationship between the period effect and legal drug control

The period effect derived from the HAPC model provides a net effect of the impact of time on marijuana use after the impact of age and birth cohort were adjusted. Findings in this study indicate that there was a progressive decline in the period effect during 1979 and 1992. This trend was corresponding to a period with the strongest legal actions at the national level, the War on Drugs by President Nixon (1969–1974) President Reagan (1981–1989) [ 45 ], and President Bush (1989) [ 45 ],and the Anti-Drug Abuse Act (1986) [ 5 ].

The estimated period effect shows an increasing trend in 1992–2001. During this period, President Clinton advocated for the use of treatment to replace incarceration (1992) [ 45 ], Surgeon General Elders proposed to study marijuana legalization (1993–1994) [ 8 ], President Clinton’s position of the need to re-examine the entire policy against people who use drugs, and decriminalization of marijuana (2000) [ 45 ] and the passage of MML in eight US states.

The estimated period effect shows a declining trend in 2001–2006. Important laws/regulations include the Student Drug Testing Program promoted by President Bush, and the broadened the public schools’ authority to test illegal drugs among students given by the US Supreme Court (2002) [ 46 ].

The estimated period effect increases in 2006–2016. This is the period when the proportion of the population covered by MML progressively increased. This relation was further proved by a positive correlation between the estimated period effect and the proportion of the population covered by MML. In addition, several other events occurred. For example, over 500 economists wrote an open letter to President Bush, Congress and Governors of the US and called for marijuana legalization (2005) [ 47 ], and President Obama ended the federal interference with the state MML, treated marijuana as public health issues, and avoided using the term of “War on Drugs” [ 45 ]. The study also indicates that the proportion of population covered by RML was positively associated with the period effect although not significant which may be due to the limited number of data points of RML. Future studies may follow up to investigate the relationship between RML and rate of marijuana use.

Coincident relationship between the cohort effect and legal drug control

Cohort effect is the risk of marijuana use associated with the specific year of birth. People born in different years are exposed to different laws, regulations in the past, therefore, the risk of marijuana use for people may differ when they enter adolescence and adulthood. Findings in this study indicate three distinctive cohorts: HDC (1954–1972), SIC (1972–1984) and CDC (1984–2003). During HDC, the overall level of marijuana use was declining. Various laws/regulations of drug use in general and marijuana in particular may explain the declining trend. First, multiple laws passed to regulate the marijuana and other substance use before and during this period remained in effect, for example, the Marijuana Tax Act (1937), the Boggs Act (1952), the Narcotics Control Act (1956) and the Controlled Substance Act (1970). Secondly, the formation of government departments focusing on drug use prevention and control may contribute to the cohort effect, such as the Bureau of Narcotics and Dangerous Drugs (1968) [ 48 ]. People born during this period may be exposed to the macro environment with laws and regulations against marijuana, thus, they may be less likely to use marijuana.

Compared to people born before 1972, the cohort effect for participants born during 1972 and 1984 was in coincidence with the increased risk of using marijuana shown as SIC. This trend was accompanied by the state and federal movements for marijuana use, which may alter the social environment and public attitudes and beliefs from prohibitive to acceptive. For example, seven states passed laws to decriminalize the marijuana use and reduced the penalty for personal possession of small amount of marijuana in 1976 [ 7 ]. Four more states joined the movement in two subsequent years [ 7 ]. People born during this period may have experienced tolerated environment of marijuana, and they may become more acceptable of marijuana use, increasing their likelihood of using marijuana.

A declining cohort CDC appeared immediately after 1984 and extended to 2003. This declining cohort effect was corresponding to a number of laws, regulations and movements prohibiting drug use. Typical examples included the War on Drugs initiated by President Nixon (1980s), the expansion of the drug war by President Reagan (1980s), the highly-publicized anti-drug campaign “Just Say No” by First Lady Nancy Reagan (early 1980s) [ 45 ], and the Zero Tolerance Policies in mid-to-late 1980s [ 45 ], the Anti-Drug Abuse Act (1986) [ 5 ], the nationally televised speech of War on Drugs declared by President Bush in 1989 and the escalated War on Drugs by President Clinton (1993–2001) [ 45 ]. Meanwhile many activities of the federal government and social groups may also influence the social environment of using marijuana. For example, the Federal government opposed to legalize the cultivation of industrial hemp, and Federal agents shut down marijuana sales club in San Francisco in 1998 [ 48 ]. Individuals born in these years grew up in an environment against marijuana use which may decrease their likelihood of using marijuana when they enter adolescence and young adulthood.

This study applied the age-period-cohort model to investigate the independent age, period and cohort effects, and indicated that the model derived trends in marijuana use among adolescents and young adults were coincident with the laws and regulations on marijuana use in the United States since the 1950s. With more states legalizing marijuana use in the United States, emphasizing responsible use would be essential to protect youth from using marijuana.

Limitations

This study has limitations. First, study data were collected through a household survey, which is subject to underreporting. Second, no causal relationship can be warranted using cross-sectional data, and further studies are needed to verify the association between the specific laws/regulation and the risk of marijuana use. Third, data were available to measure single-year age up to age 21 and two-year age group up to 25, preventing researchers from examining the risk of marijuana use for participants in other ages. Lastly, data derived from NSDUH were nation-wide, and future studies are needed to analyze state-level data and investigate the between-state differences. Although a systematic review of all laws and regulations related to marijuana and other drugs is beyond the scope of this study, findings from our study provide new data from a historical perspective much needed for the current trend in marijuana legalization across the nation to get the benefit from marijuana while to protect vulnerable children and youth in the US. It provides an opportunity for stack-holders to make public decisions by reviewing the findings of this analysis together with the laws and regulations at the federal and state levels over a long period since the 1950s.

Availability of data and materials

The data of the study are available from the designated repository ( https://nsduhweb.rti.org/respweb/homepage.cfm ).

Abbreviations

Audio computer-assisted self-interviews

Age-period-cohort modeling

Computer-assisted person interviews

Cross-classified random-effects model

Contemporary Declining Cohort

Hierarchical age-period-cohort

Historical Declining Cohort

Medical Marijuana Laws

National Household Survey on Drug Abuse

National Survey on Drug Use and Health

Recreational Marijuana Laws

Sudden Increase Cohort

The United States

CDC. Marijuana and Public Health. 2017. Available from: https://www.cdc.gov/marijuana/index.htm . Accessed 13 June 2018.

SAMHSA. Results from the 2015 National Survey on Drug Use and Health: Detailed Tables. 2016 [cited 2018 Jan 31]. Available from: https://www.samhsa.gov/data/sites/default/files/NSDUH-DetTabs-2015/NSDUH-DetTabs-2015/NSDUH-DetTabs-2015.htm

Committee on the Health Effects of Marijuana: An Evidence Review and Research Agenda, Board on Population Health and Public Health Practice, Health and Medicine Division, National Academies of Sciences, Engineering, and Medicine. The health effects of cannabis and cannabinoids: the current state of evidence and recommendations for research. Washington, D.C.: National Academies Press; 2017.

Collins C. Adverse health effects of marijuana use. N Engl J Med. 2014;371(9):879.

PubMed   Google Scholar  

Belenko SR. Drugs and drug policy in America: a documentary history. Westport: Greenwood Press; 2000.

Google Scholar  

Gerber RJ. Legalizing marijuana: Drug policy reform and prohibition politics. Westport: Praeger; 2004.

Single EW. The impact of marijuana decriminalization: an update. J Public Health Policy. 1989:456–66.

Article   CAS   Google Scholar  

SFChronicle. Ex-surgeon general backed legalizing marijuana before it was cool [Internet]. 2016 [cited 2018 Oct 7]. Available from: https://www.sfchronicle.com/business/article/Ex-surgeon-general-backed-legalizing-marijuana-6799348.php

PROCON. 31 Legal Medical Marijuana States and DC. 2018 [cited 2018 Oct 4]. Available from: https://medicalmarijuana.procon.org/view.resource.php?resourceID=000881

Bifulco M, Pisanti S. Medicinal use of cannabis in Europe: the fact that more countries legalize the medicinal use of cannabis should not become an argument for unfettered and uncontrolled use. EMBO Rep. 2015;16(2):130–2.

European Monitoring Centre for Drugs and Drug Addiction. Models for the legal supply of cannabis: recent developments (Perspectives on drugs). 2016. Available from: http://www.emcdda.europa.eu/publications/pods/legal-supply-of-cannabis . Accessed 10 Jan 2020.

European Monitoring Centre for Drugs and Drug Addiction. Cannabis policy: status and recent developments. 2017. Available from: http://www.emcdda.europa.eu/topics/cannabis-policy_en#section2 . Accessed 10 Jan 2020.

Hughes B, Matias J, Griffiths P. Inconsistencies in the assumptions linking punitive sanctions and use of cannabis and new psychoactive substances in Europe. Addiction. 2018;113(12):2155–7.

Article   Google Scholar  

Anderson DM, Hansen B, Rees DI. Medical marijuana laws and teen marijuana use. Am Law Econ Rev. 2015;17(2):495-28.

United States Census Bureau. Annual Estimates of the Resident Population by Single Year of Age and Sex for the United States, States, and Puerto Rico Commonwealth: April 1, 2010 to July 1, 2016 2016 Population Estimates. 2017 [cited 2018 Mar 14]. Available from: https://factfinder.census.gov/faces/tableservices/jsf/pages/productview.xhtml?src=bkmk

Chen X, Yu B, Lasopa S, Cottler LB. Current patterns of marijuana use initiation by age among US adolescents and emerging adults: implications for intervention. Am J Drug Alcohol Abuse. 2017;43(3):261–70.

Miech R, Koester S. Trends in U.S., past-year marijuana use from 1985 to 2009: an age-period-cohort analysis. Drug Alcohol Depend. 2012;124(3):259–67.

Steinberg L. The influence of neuroscience on US supreme court decisions about adolescents’ criminal culpability. Nat Rev Neurosci. 2013;14(7):513–8.

Sarvet AL, Wall MM, Fink DS, Greene E, Le A, Boustead AE, et al. Medical marijuana laws and adolescent marijuana use in the United States: a systematic review and meta-analysis. Addiction. 2018;113(6):1003–16.

Hasin DS, Wall M, Keyes KM, Cerdá M, Schulenberg J, O’Malley PM, et al. Medical marijuana laws and adolescent marijuana use in the USA from 1991 to 2014: results from annual, repeated cross-sectional surveys. Lancet Psychiatry. 2015;2(7):601–8.

Pacula RL, Chriqui JF, King J. Marijuana decriminalization: what does it mean in the United States? National Bureau of Economic Research; 2003.

Donnelly N, Hall W, Christie P. The effects of the Cannabis expiation notice system on the prevalence of cannabis use in South Australia: evidence from the National Drug Strategy Household Surveys 1985-95. Drug Alcohol Rev. 2000;19(3):265–9.

Gorman DM, Huber JC. Do medical cannabis laws encourage cannabis use? Int J Drug Policy. 2007;18(3):160–7.

Lynne-Landsman SD, Livingston MD, Wagenaar AC. Effects of state medical marijuana laws on adolescent marijuana use. Am J Public Health. 2013 Aug;103(8):1500–6.

Pacula RL, Powell D, Heaton P, Sevigny EL. Assessing the effects of medical marijuana laws on marijuana and alcohol use: the devil is in the details. National Bureau of Economic Research; 2013.

Harper S, Strumpf EC, Kaufman JS. Do medical marijuana laws increase marijuana use? Replication study and extension. Ann Epidemiol. 2012;22(3):207–12.

Stolzenberg L, D’Alessio SJ, Dariano D. The effect of medical cannabis laws on juvenile cannabis use. Int J Drug Policy. 2016;27:82–8.

Wang GS, Roosevelt G, Heard K. Pediatric marijuana exposures in a medical marijuana state. JAMA Pediatr. 2013;167(7):630–3.

Wall MM, Poh E, Cerdá M, Keyes KM, Galea S, Hasin DS. Adolescent marijuana use from 2002 to 2008: higher in states with medical marijuana laws, cause still unclear. Ann Epidemiol. 2011;21(9):714–6.

Chen X, Yu B, Stanton B, Cook RL, Chen D-GD, Okafor C. Medical marijuana laws and marijuana use among U.S. adolescents: evidence from michigan youth risk behavior surveillance data. J Drug Educ. 2018;47237918803361.

Chen X. Information diffusion in the evaluation of medical marijuana laws’ impact on risk perception and use. Am J Public Health. 2016;106(12):e8.

Chen X, Yu B, Stanton B, Cook RL, Chen DG, Okafor C. Medical marijuana laws and marijuana use among US adolescents: Evidence from Michigan youth risk behavior surveillance data. J Drug Educ. 2018;48(1-2):18-35.

Yang Y, Land K. Age-Period-Cohort Analysis: New Models, Methods, and Empirical Applications. Boca Raton: Chapman and Hall/CRC; 2013.

Yu B, Chen X. Age and birth cohort-adjusted rates of suicide mortality among US male and female youths aged 10 to 19 years from 1999 to 2017. JAMA Netw Open. 2019;2(9):e1911383.

Akiba S. Epidemiological studies of Fukushima residents exposed to ionising radiation from the Fukushima Daiichi nuclear power plant prefecture--a preliminary review of current plans. J Radiol Prot. 2012;32(1):1–10.

Yang Y, Land KC. Age-period-cohort analysis of repeated cross-section surveys: fixed or random effects? Sociol Methods Res. 2008;36(3):297–326.

O’Brien R. Age-period-cohort models: approaches and analyses with aggregate data. Boca Raton: Chapman and Hall/CRC; 2014.

Book   Google Scholar  

Chen X, Sun Y, Li Z, Yu B, Gao G, Wang P. Historical trends in suicide risk for the residents of mainland China: APC modeling of the archived national suicide mortality rates during 1987-2012. Soc Psychiatry Psychiatr Epidemiol. 2018;54(1):99–110.

Yang Y. Social inequalities in happiness in the United States, 1972 to 2004: an age-period-cohort analysis. Am Sociol Rev. 2008;73(2):204–26.

Reither EN, Hauser RM, Yang Y. Do birth cohorts matter? Age-period-cohort analyses of the obesity epidemic in the United States. Soc Sci Med. 2009;69(10):1439–48.

Kerr WC, Lui C, Ye Y. Trends and age, period and cohort effects for marijuana use prevalence in the 1984-2015 US National Alcohol Surveys. Addiction. 2018;113(3):473–81.

Johnson RA, Gerstein DR. Age, period, and cohort effects in marijuana and alcohol incidence: United States females and males, 1961-1990. Substance Use Misuse. 2000;35(6–8):925–48.

Substance Abuse and Mental Health Services Administration. Results from the 2013 NSDUH: Summary of National Findings, SAMHSA, CBHSQ. 2014 [cited 2018 Sep 23]. Available from: https://www.samhsa.gov/data/sites/default/files/NSDUHresultsPDFWHTML2013/Web/NSDUHresults2013.htm

Bauer DJ, Hussong AM. Psychometric approaches for developing commensurate measures across independent studies: traditional and new models. Psychol Methods. 2009;14(2):101–25.

Drug Policy Alliance. A Brief History of the Drug War. 2018 [cited 2018 Sep 27]. Available from: http://www.drugpolicy.org/issues/brief-history-drug-war

NIDA. Drug testing in schools. 2017 [cited 2018 Sep 27]. Available from: https://www.drugabuse.gov/related-topics/drug-testing/faq-drug-testing-in-schools

Wikipedia contributors. Legal history of cannabis in the United States. 2015. Available from: https://en.wikipedia.org/w/index.php?title=Legal_history_of_cannabis_in_the_United_States&oldid=674767854 . Accessed 24 Oct 2017.

NORML. Marijuana law reform timeline. 2015. Available from: http://norml.org/shop/item/marijuana-law-reform-timeline . Accessed 24 Oct 2017.

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Additional file 1: table s1..

Estimated Age, Period, Cohort Effects for the Trend of Marijuana Use in Past Month among Adolescents and Emerging Adults Aged 12 to 25 Years, NSDUH, 1979-2016. Table S2. Laws at the federal and state levels related to marijuana use.

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Yu, B., Chen, X., Chen, X. et al. Marijuana legalization and historical trends in marijuana use among US residents aged 12–25: results from the 1979–2016 National Survey on drug use and health. BMC Public Health 20 , 156 (2020). https://doi.org/10.1186/s12889-020-8253-4

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The Public Health Effects of Legalizing Marijuana

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Estimated coefficients are shown for the overall population, adults, and youths; error bars indicate 95% CIs. The year before implementation was the reference (omitted) year. The estimated coefficient should be interpreted as relative to this year. The final lag or lead points accumulated all years beyond (ie, −4 included year −4 and earlier; 3 included year 3 and later). All regressions also included controls for the presence of medical cannabis legalization, share of the population with less than a high school diploma or equivalent, share of female individuals in the population, share of individuals in the population from racial and ethnic minority groups, share of youths in the population, number of police officers per 1000 population, unemployment rate, income per capita in 2019 thousand dollars, poverty rate, state and year indicators, and state-specific time trends. Standard errors were clustered at the state level. All regressions were weighted by state population averaged over the study period (2010-2019).

Estimated coefficients are shown for the overall population, adults, and youths by racial group; error bars indicate 95% CIs. The year before implementation was the reference (omitted) year. The estimated coefficient should be interpreted as relative to this year. The final lag or lead points accumulated all years beyond (ie, −4 included year −4 and earlier; 3 included year 3 and later). All regressions also included controls for the presence of medical cannabis legalization, share of the population with less than a high school diploma or equivalent, share of female individuals in the population, share of individuals in the population from racial and ethnic minority groups, share of youths in the population, number of police officers per 1000 population, unemployment rate, income per capita in 2019 thousand dollars, poverty rate, state and year indicators, and state-specific time trends. Standard errors were clustered at the state level. All regressions were weighted by state population averaged over the study period (2010-2019).

eTable 1. States Included and Excluded in the Study

eFigure 1. Trends in Overall Cannabis Possession Arrest Rates in Recreational Cannabis Legalization States

eFigure 2. Trends in Adult Cannabis Possession Arrest Rates in Recreational Cannabis Legalization States

eFigure 3. Trends in Youth Cannabis Possession Arrest Rates in Recreational Cannabis Legalization States

eTable 2. Regression Results for the Overall Population: Recreational Cannabis Legalization States Without Cannabis Decriminalization Already in Place

eTable 3. Regression Results for Adults: Recreational Cannabis Legalization States Without Cannabis Decriminalization Already in Place

eTable 4. Regression Results for Youths: Recreational Cannabis Legalization States Without Cannabis Decriminalization Already in Place

eTable 5. Regression Results for the Overall Population: Recreational Cannabis Legalization States With Cannabis Decriminalization Already in Place

eTable 6. Regression Results for Adults: Recreational Cannabis Legalization States With Cannabis Decriminalization Already in Place

eTable 7. Regression Results for Youths: Recreational Cannabis Legalization States With Cannabis Decriminalization Already in Place

eFigure 4. Leave-One-Out Analysis for Recreational Cannabis Legalization States Without Decriminalization Already in Place

eFigure 5. Leave-One-Out Analysis for Recreational Cannabis Legalization States With Decriminalization Already in Place

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Gunadi C , Shi Y. Association of Recreational Cannabis Legalization With Cannabis Possession Arrest Rates in the US. JAMA Netw Open. 2022;5(12):e2244922. doi:10.1001/jamanetworkopen.2022.44922

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Association of Recreational Cannabis Legalization With Cannabis Possession Arrest Rates in the US

• 1 Herbert Wertheim School of Public Health and Human Longevity Science, University of California San Diego, La Jolla

Question   Is recreational cannabis legalization (RCL) associated with a reduction in cannabis possession arrest rates in US states that have already decriminalized cannabis; if so, does this change differ by age and race?

Findings   In this cross-sectional study using difference-in-differences analysis for data from 31 states, RCL was associated with a 40% reduction in cannabis possession arrest rates among adults in the 5 states that had already decriminalized cannabis between 2010 and 2019. This decrease was significantly smaller than that for the 4 states that had not decriminalized cannabis (76%), and there was no association between RCL and changes in youth arrest rates or disparities in arrest rates among Black and White individuals.

Meaning   These findings suggest that RCL was associated with decreased cannabis possession arrest rates among adults during the study period, even in US states that had already decriminalized cannabis.

Importance   Recreational cannabis legalization (RCL) has been advocated as a way to reduce the number of individuals interacting with the US criminal justice system; in theory, however, cannabis decriminalization can achieve this objective without generating the negative public health consequences associated with RCL. It is still unclear whether RCL can bring additional benefits in terms of reducing cannabis possession arrests in states that have already decriminalized cannabis.

Objective   To examine whether RCL was associated with changes in cannabis possession arrests in US states that had already decriminalized cannabis during the study period and whether these changes differed across age and racial subgroups.

Design, Setting, and Participants   This repeated cross-sectional study used cannabis possession arrest data from the Federal Bureau of Investigation Uniform Crime Reporting Program (UCRP) for US states from 2010 through 2019. Statistical analysis was conducted from October 6, 2021, to October 12, 2022.

Exposures   Implementation of statewide RCL.

Main Outcomes and Measures   Cannabis possession arrest rates per 1000 population per year were assessed with a quasi-experimental difference-in-differences design and were used to estimate the association of RCL with arrest rates in RCL states that had or had not decriminalized cannabis before RCL. This association was also examined in subgroups for age (adults vs youths) and race (Black vs White).

Results   This study included UCRP data for 31 US states, including 9 states that implemented RCL during the study period (4 without and 5 with decriminalization) and 22 non-RCL states. In the 4 states that had not decriminalized cannabis before legalization, RCL was associated with a 76.3% decrease (95% CI, −81.2% to −69.9%) in arrest rates among adults. In the 5 states that had already decriminalized cannabis, RCL was still associated with a substantial decrease in adult arrest rates (−40.0%; 95% CI, −55.1% to −19.8%). There was no association of RCL with changes in arrest rates among youths. In addition, changes in arrest rates associated with RCL did not differ among Black and White individuals.

Conclusions and Relevance   In this repeated cross-sectional study, RCL was associated with a sizable reduction in cannabis possession arrests among adults in states that had already decriminalized cannabis during the study period (2010-2019), albeit the magnitude was smaller compared with states that had not decriminalized cannabis before RCL. In addition, RCL did not seem to be associated with changes in arrest rates among youths or disparities in arrest rates among Black and White individuals.

In 2012, Colorado and Washington became the first US states to implement recreational cannabis legalization (RCL), which allows the possession of a small amount of cannabis for adult use without any penalties. Since then, 16 states and the District of Columbia have followed suit. 1 One reason for this momentum is the increasing recognition that cannabis illegality sends a large number of individuals to the criminal justice system, with adverse physical, mental, and social consequences. 2

To reduce the number of cannabis possession arrests, civil liberties advocates have voiced support for RCL. 2 In theory, however, a reduction in cannabis possession arrests can be achieved by decriminalizing cannabis, which changes the penalties associated with a small amount of cannabis possession from criminal to civil infractions. In fact, more than 30 states have adopted cannabis decriminalization since the 1970s. The latest research estimates that during the 2010s, cannabis possession arrest rates were reduced substantially among both adults and youths (by 40%-80%) as a result of decriminalization. 3 - 5 Cannabis decriminalization and RCL have substantial differences in terms of motivations, enactment, provisions, and enforcements. Both, however, have the potential to reduce cannabis possession arrests. If the policy goal is solely to reduce arrests, decriminalization may seem to be more appealing than RCL. First, under cannabis decriminalization, individuals caught possessing a small amount of cannabis are still subject to civil penalties (eg, fines, mandated drug education programs, or public services) but do not receive criminal sanctions. The civil penalties may serve as a deterrent to cannabis use and prevent related adverse consequences. Second, RCL could allow the legal sale of cannabis, which increases access and exposure to cannabis products and marketing activities. The legality of cannabis may also make social norms more favorable to cannabis. Some studies have shown that RCL is associated with increased use of cannabis among both adults and youths, creating considerable public health concerns. 6 - 9

In contrast, RCL has potential to further reduce cannabis possession arrests on top of decriminalization. Under RCL, law enforcement agents are no longer required to look for cannabis possession violations in a small amount. Although possession of a large amount of cannabis is still a criminal offense under both decriminalization and RCL, an overall lower police search rate under RCL will likely lead to a large reduction in arrests even in states that have already decriminalized cannabis.

We are aware of only 1 study that has examined the association of RCL with cannabis possession arrests. 5 In a comparison of 4 US states that implemented RCL from 2000 to 2016 with other states that did not change penalties for cannabis possession in the same period, Plunk et al 5 found that RCL was associated with a substantial decline in arrest rates among adults but not youths. The authors did not distinguish RCL states that had already decriminalized cannabis from those that had not. 5 It remains unclear whether RCL can further reduce cannabis possession arrests in states that have already decriminalized cannabis.

This study had 2 objectives. First, we examined whether RCL implementation was associated with a reduction in cannabis possession arrests in states that had already decriminalized cannabis. If no evidence was found, it might be plausible for policy makers in states already implementing decriminalization to consider alternative strategies other than RCL to further reduce arrests. We also examined whether the association existed in states without cannabis decriminalization. If no evidence was found, decriminalization might be considered a more effective and safer strategy of reducing arrests without the potential negative consequences associated with RCL.

Second, we assessed whether the association of RCL with cannabis possession arrests differed by age (adults vs youths) and race (Black vs White). Recreational cannabis has been legalized only for adult use, which in theory should have minimal effects on arrests of youths. According to a previous American Civil Liberties Union report, Black individuals were considerably more likely to be arrested for cannabis possession compared with White individuals, despite a similar rate of cannabis use. 10 The magnitude of the change in arrests after RCL could therefore differ among Black and White individuals.

This cross-sectional study used publicly available secondary data sources and was therefore deemed exempt from institutional review board approval and informed consent per University of California San Diego policy. The study followed the Strengthening the Reporting of Observational Studies in Epidemiology ( STROBE ) reporting guideline.

Data on cannabis possession arrests by age, sex, and race were obtained from the Uniform Crime Reporting Program (UCRP) for 2010 to 2019. 11 The UCRP is assembled from more than 18 000 law enforcement agencies and maintained by the US Federal Bureau of Investigation, and it is one of the most widely used data sources to examine crimes in the US. 4 , 5 , 12

UCRP arrest data have limitations. First, reporting to the UCRP by law enforcement agencies is voluntary; hence, some states in some periods may have incomplete data. In particular, Florida did not report arrest statistics for most years (2010-2016) in the study period; we thus excluded Florida from this study. Second, there was a misreporting in the number of arrests by the Denver Police Department after cannabis was legalized in Colorado. 5 Because this department is one of the largest police divisions in Colorado, misreporting in Denver could result in incorrect statistics for the entire state; we consequently excluded Colorado from this study. Third, information on arrests by race and ethnicity was limited. Race information was available only for American Indian or Alaska Native, Asian, Black, and White individuals. Data on American Indian or Alaska Native and Asian individuals were not assessed in this study because cannabis possession arrests among these groups are rare and the disparity in arrest rates is most striking between Black and White individuals. Ethnicity information, such as Hispanic origin, was unavailable for most of the study period. Race and ethnicity information is often reported by officers and subject to inaccuracy. Finally, the UCRP adheres to the hierarchy rule in its reporting, such that less severe crimes (part II offenses) like cannabis possession are reported only if they occur during an incident without the more severe crimes (part I offenses). 13

Our main outcome was annual cannabis possession arrest rates per 1000 population at the state level. The state-level population estimates were obtained from the Integrated Public Use Microdata Series American Community Survey (ACS) for 2010 to 2019. 14 The rates were calculated separately in adult and youth populations and separately for Black and White individuals. Although the legal purchase age for recreational cannabis was 21 years in all RCL states, we used age 18 years as the cutoff to define adults and youths in this study because the UCRP reports arrests by race in only 2 age categories based on this cutoff. 11 Eighteen years was also used as the cutoff age in previous literature. 4 , 5 , 12

The state-level policy exposure was a binary indicator taking the value of 1 if RCL was in effect in a year and a state and 0 otherwise.

There were 9 states that implemented RCL in the study period (eTable 1 in Supplement 1 ). Two groups of RCL states were constructed as follows based on whether cannabis decriminalization was already in place before RCL implementation 4 , 5 , 15 - 17 : (1) RCL states without decriminalization already in place, including Washington, Alaska, Nevada, and Michigan; and (2) RCL states with decriminalization already in place, including Oregon, California, Massachusetts, Maine, and Vermont. Because California and Vermont decriminalized cannabis during the study period, we excluded their state–year observations before and in the year of decriminalization. These 2 groups of RCL states were analyzed separately to allow differential effects of RCL by decriminalization status.

The comparison group consisted of 22 states that neither implemented RCL nor changed penalties for cannabis possession in the study period (ie, non-RCL states). 4 , 5 , 15 - 17 Seventeen states that did not implement RCL were excluded from the study because they either decriminalized cannabis or changed penalties for cannabis possession during the study period. 2 , 4 , 5 eTable 1 in Supplement 1 lists all included and excluded states.

Following previous studies, time-varying state-level covariates that may confound the association of RCL with cannabis possession arrests were included in the regressions. 3 - 5 These covariates included the share of the population with less than a high school diploma or equivalent, share of female individuals in the population, share of individuals in the population from racial and ethnic minority groups, share of youths in the population, number of police officers per 1000 population, unemployment rate, income per capita in 2019 thousand dollars, and poverty rate. These state-level characteristics were constructed from ACS and UCRP data on law enforcement officers killed and assaulted. 18 The binary indicator for the presence of medical cannabis legalization was also included in the regressions, taking the value of 1 if it was in effect in a year and a state and 0 otherwise. 4 , 5 The effective dates of medical cannabis legalization were obtained from ProCon.org.

The unit of analysis was state–year observations. To examine the association of RCL with cannabis possession arrest rates, we used the quasi-experimental difference-in-differences research design. Specifically, we used log-linear regression to model arrest rates as a function of RCL, adjusting for all covariates mentioned in the previous section, fixed effects for state and year, and state-specific time trends. State fixed effects (indicators of states) accounted for potential state-specific confounding factors that did not vary over time. Year fixed effects (indicators of years) accounted for secular trends in outcomes common to all states in the same year. State-specific time trends (linear trend variable for each state) accounted for state-specific confounding factors that varied linearly over time. Two types of RCL states (with and without cannabis decriminalization) were compared with comparison states separately. The analysis was also conducted separately for adults and youths and for Black and White individuals.

Vermont reported 0 cannabis possession arrests for Black adults in 2015 and 2019. To avoid dropping these state–year observations, we added a small constant (0.01) to all state–year observations for log transformation in all race-related analysis. Our results were not sensitive to this specification.

As noted earlier, the voluntary reporting to UCRP potentially exerts bias in the estimated association due to measurement error. Because this error was more severe in areas with a small population size, we followed previous studies to weight the regression by state population size averaged over the entire study period to minimize potential bias. 19 , 20 Standard errors were clustered at the state level to account for possible serial correlation within a state. 21

We formally tested differences in the effects of RCL among (1) RCL states with and without decriminalization already in place, (2) adults and youths, and (3) Black and White individuals. Specifically, we used seemingly unrelated estimation and tested the equality between regression coefficients in the comparison.

We also conducted 2 supplemental analyses. First, we conducted an event study by replacing the RCL indicator with a series of its leads and lags to examine whether the estimated association was driven by the difference in prelegalization trends between RCL and non-RCL states. Second, we conducted a leave-one-out exercise by dropping 1 RCL state from the regression at a time to examine whether the overall estimate was driven by a specific RCL state. P  < .05 was considered statistically significant. Statistical analyses were performed with Stata, version 16 (StataCorp LLC).

Table 1 reports outcome and covariate statistical results by state RCL and decriminalization status. eFigure 1 in Supplement 1 plots trends in cannabis possession arrest rates in RCL states during the study period. We observed a substantial decrease in arrest rates after RCL was implemented in states that had already decriminalized cannabis, although this decline seemed smaller compared with RCL states that had not decriminalized cannabis. The magnitude of the decline seemed to be similar between Black and White individuals regardless of state decriminalization status. The decrease in arrest rate seemed to be driven by adults but not youths (eFigures 2 and 3 in Supplement 1 , respectively).

Table 2 reports association estimation results from regressions (detailed results in eTables 2-7 in Supplement 1 ). Table 3 reports the test statistics for the differences in association coefficients among (1) RCL states with and without cannabis decriminalization, (2) adults and youths, and (3) Black and White individuals.

Recreational cannabis legalization was associated with a 68.6% decline (95% CI, −75.6% to −59.8%) in arrest rates in RCL states that had not decriminalized cannabis before RCL and a 33.0% decline (95% CI, −49.3% to −11.3%) in RCL states that had already decriminalized cannabis. The association difference in the 2 types of RCL states was statistically significant ( P  < .001).

Among adults, RCL was associated with a 76.3% decline (95% CI, −81.2% to −69.9%) in arrest rates in RCL states that had not decriminalized cannabis before RCL and a 40.0% decline (95% CI, −55.1% to −19.8%) in RCL states that had already decriminalized cannabis. Among youths, RCL was not associated with a change in arrest rate.

In RCL states that had not decriminalized cannabis before legalization, RCL was associated with a 77.9% decline (95% CI, −84.3% to −69.3%) in arrest rates among Black adults and a 74.6% decline (95% CI, −79.0% to −69.3%) among White adults. In RCL states that had already decriminalized cannabis before legalization, RCL was associated with a 35.0% decline (95% CI, −55.5% to −5.5%) in arrest rates among Black adults and a 41.1% decline (95% CI, −55.1% to −23.7%) among White adults. However, there was no evidence that the decreases differed between Black and White adults in either type of RCL state. There was no association between RCL and arrest rate in Black or White youths.

Figure 1 and Figure 2 report results from the event study. It appeared that the estimated associations were not driven by differences in prelegalization trends between RCL and non-RCL states. The validity of the difference-in-differences design was hence supported. The association might be dynamic: in most cases, the decline seemed to be larger in magnitude after the year of RCL implementation. The dynamic association should be interpreted with caution, however, because some states had very limited time points in the post-RCL period.

eFigures 4 and 5 in Supplement 1 report results from the leave-one-out analysis. Overall, it seems that the main findings were not driven by a specific RCL state.

This cross-sectional study examined the association of RCL with changes in cannabis possession arrests and tested whether the association differed between RCL states with and without decriminalization already in place. Our results suggest that RCL was associated with a substantial decrease in adult arrest rates in both types of RCL states for the study period (2010-2019). For adults, the magnitude of the decrease (40.0%-76.3%) associated with RCL was comparable to that associated with cannabis decriminalization. 3 - 5 States that had already decriminalized cannabis before RCL saw a smaller magnitude of decline (40.0%) than states that had not decriminalized cannabis before RCL (76.3%). These findings suggest that implementing RCL may be associated with a further reduction in adult arrest rates even after a state decriminalizes cannabis.

Consistent with a 2019 study by Plunk et al, 5 we did not find an association between RCL and cannabis possession arrests among youths regardless of decriminalization status in RCL states. This finding was not surprising because RCL intends to legalize cannabis use among adults but not youths. If youth arrest is more concerning because of the prolonged, adverse health and socioeconomic consequences from adolescence to adulthood, 22 cannabis decriminalization may be a preferred strategy because it removes criminal penalties not only for adults but also youths and also reduces arrests in both age groups. 3 - 5

Despite similar rates of cannabis use, Black individuals are reportedly 3 to 4 times more likely to be arrested for cannabis possession compared with White individuals. 10 A previous study estimated that cannabis decriminalization was associated with an approximately 17.0% reduction in racial disparities in arrests among Black and White adults. 3 Our results suggest that RCL might not provide additional benefits in terms of reducing racial disparities compared with decriminalization. Nonetheless, we should note that the decrease in cannabis possession arrests after RCL was substantial for both Black and White adults, demonstrating an overall change in law enforcement behaviors.

If we compare the benefits of RCL and cannabis decriminalization based solely on their associations with cannabis possession arrests, this study and the existing literature suggest that both RCL and decriminalization are associated with a sizable reduction in adult arrest rates. 3 - 5 Even after decriminalization was implemented, adults could still benefit from a further reduction in arrests under RCL. The argument that RCL could reduce individual contact with the criminal justice system is supported. Nonetheless, decriminalization has additional benefits; for example, it was also associated with reductions in arrests among youths and in racial disparities among Black and White individuals. 3 That said, the choice of RCL and decriminalization approaches should be made with a holistic evaluation of all benefits and costs. The effect on the criminal justice system is a major consideration but should not be the only one. Other considerations could include effects on public health, 6 the economy, and society. Policy makers are encouraged to adopt a strategy only when the total benefits outweigh the total costs.

This cross-sectional study is not without limitations. First, police agency reporting to the UCRP is voluntary. To account for measurement errors, we followed previous studies to weight the regressions by population. 19 , 20 However, this approach may not have fully eliminated the bias. Second, cannabis possession arrests may be underestimated due to the hierarchical reporting in the UCRP. We believe that it should not bias the difference-in-differences estimates unless RCL implementation was associated with changes in the reporting method or the volume of severe crimes. Third, UCRP information on race may be inaccurate. Fourth, we were not able to examine other races or ethnicities due to data limitations. Fifth, time-varying unobserved confounding factors may not have been fully accounted for by the difference-in-differences design. Furthermore, findings from the 9 RCL states may not necessarily generalize to other US states or outside of the US setting. Finally, it may take time for the effects on law enforcement behaviors to fully materialize after RCL. The post-RCL period in this study might be too short to capture changes in youths and racial disparities. A re-examination with a longer post-RCL period is warranted.

The findings of this repeated cross-sectional study suggest that RCL was associated with a substantial decrease in adult arrests in US states that had already decriminalized cannabis, albeit of a smaller magnitude compared with RCL states that had not. RCL did not appear to be associated with changes in arrest rates among youths or disparities in arrest rates among Black and White individuals.

Accepted for Publication: October 18, 2022.

Published: December 5, 2022. doi:10.1001/jamanetworkopen.2022.44922

Open Access: This is an open access article distributed under the terms of the CC-BY License . © 2022 Gunadi C et al. JAMA Network Open .

Corresponding Author: Yuyan Shi, PhD, Herbert Wertheim School of Public Health and Human Longevity Science, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093-0628 ( [email protected] ).

Author Contributions: Drs Gunadi and Shi had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Shi.

Acquisition, analysis, or interpretation of data: Both authors.

Drafting of the manuscript: Both authors.

Critical revision of the manuscript for important intellectual content: Shi.

Statistical analysis: Gunadi.

Obtained funding: Shi.

Administrative, technical, or material support: Shi.

Supervision: Shi.

Conflict of Interest Disclosures: Dr Gunadi reported receiving grants from the National Institute on Drug Abuse during the conduct of the study. Dr Shi reported receiving grants from the National Institute on Drug Abuse during the conduct of the study.

Funding/Support: This work was supported by award numbers R01DA042290 and R01DA049730 from the National Institute on Drug Abuse (Dr Shi).

Role of the Funder/Sponsor: The funder had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Data Sharing Statement: See Supplement 2 .

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Americans overwhelmingly say marijuana should be legal for medical or recreational use.

With a growing number of states authorizing the use of marijuana, the public continues to broadly favor legalization of the drug for medical and recreational purposes. 

An overwhelming share of U.S. adults (88%) say either that marijuana should be legal for medical and recreational use by adults (59%) or that it should be legal for medical use only (30%). Just one-in-ten (10%) say marijuana use should not be legal, according to a Pew Research Center survey conducted Oct. 10-16, 2022. These views are virtually unchanged since April 2021.

The new survey follows President Joe Biden’s decision to pardon people convicted of marijuana possession at the federal level and direct his administration to review how marijuana is classified under federal law. It was fielded before the Nov. 8 midterm elections, when two states legalized the use of marijuana for recreational purposes – joining 19 states and the District of Columbia , which had already done so.

Pew Research Center asked this question to track public views about the legal status of marijuana. For this analysis, we surveyed 5,098 adults from Oct. 10-16, 2022. Everyone who took part in this survey is a member of the Center’s American Trends Panel (ATP), an online survey panel that is recruited through national, random sampling of residential addresses. This way nearly all U.S. adults have a chance of selection. The survey is weighted to be representative of the U.S. adult population by gender, race, ethnicity, partisan affiliation, education and other categories. Read more about the ATP’s methodology .

Here are the questions used for this report, along with responses, and its methodology .

Over the long term, there has been a steep rise in public support for marijuana legalization, as measured by a separate Gallup survey question that asks whether the use of marijuana should be made legal – without specifying whether it would be legalized for recreational or medical use. This year, 68% of adults say marijuana should be legal , matching the record-high support for legalization Gallup found in 2021.

There continue to be sizable age and partisan differences in Americans’ views about marijuana. While very small shares of adults of any age are completely opposed to the legalization of the drug, older adults are far less likely than younger ones to favor legalizing it for recreational purposes.

This is particularly the case among those ages 75 and older, just three-in-ten of whom say marijuana should be legal for both medical and recreational use. Larger shares in every other age group – including 53% of those ages 65 to 74 – say the drug should be legal for both medical and recreational use.

Republicans are more wary than Democrats about legalizing marijuana for recreational use: 45% of Republicans and Republican-leaning independents favor legalizing marijuana for both medical and recreational use, while an additional 39% say it should only be legal for medical use. By comparison, 73% of Democrats and Democratic leaners say marijuana should be legal for both medical and recreational use; an additional 21% say it should be legal for medical use only.

Ideological differences are evident within each party. About four-in-ten conservative Republicans (37%) say marijuana should be legal for medical and recreational use, compared with a 60% majority of moderate and liberal Republicans.

Nearly two-thirds of conservative and moderate Democrats (63%) say marijuana should be legal for medical and recreational use. An overwhelming majority of liberal Democrats (84%) say the same.

There also are racial and ethnic differences in views of legalizing marijuana. Roughly two-thirds of Black adults (68%) and six-in-ten White adults say marijuana should be legal for medical and recreational use, compared with smaller shares of Hispanic (49%) and Asian adults (48%).

Related: Clear majorities of Black Americans favor marijuana legalization, easing of criminal penalties

In both parties, views of marijuana legalization vary by age

While Republicans and Democrats differ greatly on whether marijuana should be legal for medial and recreational use, there are also age divides within each party.

A 62% majority of Republicans ages 18 to 29 favor making marijuana legal for medical and recreational use, compared with 52% of those ages 30 to 49. Roughly four-in-ten Republicans ages 50 to 64 (41%) and 65 to 74 (38%) say marijuana should be legal for both purposes, as do 18% of those 75 and older.

Still, wide majorities of Republicans in all age groups favor legalizing marijuana for medical use. Even among Republicans 65 and older, just 17% say marijuana use should not be legal even for medical purposes.

While majorities of Democrats across all age groups support legalizing marijuana for medical and recreational use, older Democrats are less likely to say this. About half of Democrats ages 75 and older (51%) say marijuana should be legal for medical or recreational purposes; larger shares of younger Democrats say the same. Still, only 8% of Democrats 75 and older think marijuana should not be legalized even for medical use – similar to the share of all other Democrats who say this.

Note: Here are the questions used for this report, along with responses, and its methodology .

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Clear majorities of Black Americans favor marijuana legalization, easing of criminal penalties

Concern about drug addiction has declined in u.s., even in areas where fatal overdoses have risen the most, religious americans are less likely to endorse legal marijuana for recreational use, 6 facts about americans and marijuana, four-in-ten u.s. drug arrests in 2018 were for marijuana offenses – mostly possession, most popular.

About Pew Research Center Pew Research Center is a nonpartisan fact tank that informs the public about the issues, attitudes and trends shaping the world. It conducts public opinion polling, demographic research, media content analysis and other empirical social science research. Pew Research Center does not take policy positions. It is a subsidiary of The Pew Charitable Trusts .

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The Evidence—and Lack Thereof—About Cannabis

Research is still needed on cannabis’s risks and benefits. 

Lindsay Smith Rogers

Although the use and possession of cannabis is illegal under federal law, medicinal and recreational cannabis use has become increasingly widespread.

Thirty-eight states and Washington, D.C., have legalized medical cannabis, while 23 states and D.C. have legalized recreational use. Cannabis legalization has benefits, such as removing the product from the illegal market so it can be taxed and regulated, but science is still trying to catch up as social norms evolve and different products become available. 

In this Q&A, adapted from the August 25 episode of Public Health On Call , Lindsay Smith Rogers talks with Johannes Thrul, PhD, MS , associate professor of Mental Health , about cannabis as medicine, potential risks involved with its use, and what research is showing about its safety and efficacy. 

Do you think medicinal cannabis paved the way for legalization of recreational use?

The momentum has been clear for a few years now. California was the first to legalize it for medical reasons [in 1996]. Washington and Colorado were the first states to legalize recreational use back in 2012. You see one state after another changing their laws, and over time, you see a change in social norms. It's clear from the national surveys that people are becoming more and more in favor of cannabis legalization. That started with medical use, and has now continued into recreational use.

But there is a murky differentiation between medical and recreational cannabis. I think a lot of people are using cannabis to self-medicate. It's not like a medication you get prescribed for a very narrow symptom or a specific disease. Anyone with a medical cannabis prescription, or who meets the age limit for recreational cannabis, can purchase it. Then what they use it for is really all over the place—maybe because it makes them feel good, or because it helps them deal with certain symptoms, diseases, and disorders.

Does cannabis have viable medicinal uses?

The evidence is mixed at this point. There hasn’t been a lot of funding going into testing cannabis in a rigorous way. There is more evidence for certain indications than for others, like CBD for seizures—one of the first indications that cannabis was approved for. And THC has been used effectively for things like nausea and appetite for people with cancer.

There are other indications where the evidence is a lot more mixed. For example, pain—one of the main reasons that people report for using cannabis. When we talk to patients, they say cannabis improved their quality of life. In the big studies that have been done so far, there are some indications from animal models that cannabis might help [with pain]. When we look at human studies, it's very much a mixed bag. 

And, when we say cannabis, in a way it's a misnomer because cannabis is so many things. We have different cannabinoids and different concentrations of different cannabinoids. The main cannabinoids that are being studied are THC and CBD, but there are dozens of other minor cannabinoids and terpenes in cannabis products, all of varying concentrations. And then you also have a lot of different routes of administration available. You can smoke, vape, take edibles, use tinctures and topicals. When you think about the explosion of all of the different combinations of different products and different routes of administration, it tells you how complicated it gets to study this in a rigorous way. You almost need a randomized trial for every single one of those and then for every single indication.

What do we know about the risks of marijuana use?  

Cannabis use disorder is a legitimate disorder in the DSM. There are, unfortunately, a lot of people who develop a problematic use of cannabis. We know there are risks for mental health consequences. The evidence is probably the strongest that if you have a family history of psychosis or schizophrenia, using cannabis early in adolescence is not the best idea. We know cannabis can trigger psychotic symptoms and potentially longer lasting problems with psychosis and schizophrenia. 

It is hard to study, because you also don't know if people are medicating early negative symptoms of schizophrenia. They wouldn't necessarily have a diagnosis yet, but maybe cannabis helps them to deal with negative symptoms, and then they develop psychosis. There is also some evidence that there could be something going on with the impact of cannabis on the developing brain that could prime you to be at greater risk of using other substances later down the road, or finding the use of other substances more reinforcing. 

What benefits do you see to legalization?

When we look at the public health landscape and the effect of legislation, in this case legalization, one of the big benefits is taking cannabis out of the underground illegal market. Taking cannabis out of that particular space is a great idea. You're taking it out of the illegal market and giving it to legitimate businesses where there is going to be oversight and testing of products, so you know what you're getting. And these products undergo quality control and are labeled. Those labels so far are a bit variable, but at least we're getting there. If you're picking up cannabis at the street corner, you have no idea what's in it. 

And we know that drug laws in general have been used to criminalize communities of color and minorities. Legalizing cannabis [can help] reduce the overpolicing of these populations.

What big questions about cannabis would you most like to see answered?

We know there are certain, most-often-mentioned conditions that people are already using medical cannabis for: pain, insomnia, anxiety, and PTSD. We really need to improve the evidence base for those. I think clinical trials for different cannabis products for those conditions are warranted.

Another question is, now that the states are getting more tax revenue from cannabis sales, what are they doing with that money? If you look at tobacco legislation, for example, certain states have required that those funds get used for research on those particular issues. To me, that would be a very good use of the tax revenue that is now coming in. We know, for example, that there’s a lot more tax revenue now that Maryland has legalized recreational use. Maryland could really step up here and help provide some of that evidence.

Are there studies looking into the risks you mentioned?

Large national studies are done every year or every other year to collect data, so we already have a pretty good sense of the prevalence of cannabis use disorder. Obviously, we'll keep tracking that to see if those numbers increase, for example, in states that are legalizing. But, you wouldn't necessarily expect to see an uptick in cannabis use disorder a month after legalization. The evidence from states that have legalized it has not demonstrated that we might all of a sudden see an increase in psychosis or in cannabis use disorder. This happens slowly over time with a change in social norms and availability, and potentially also with a change in marketing. And, with increasing use of an addictive substance, you will see over time a potential increase in problematic use and then also an increase in use disorder.

If you're interested in seeing if cannabis is right for you, is this something you can talk to your doctor about?

I think your mileage may vary there with how much your doctor is comfortable and knows about it. It's still relatively fringe. That will very much depend on who you talk to. But I think as providers and professionals, everybody needs to learn more about this, because patients are going to ask no matter what.

Lindsay Smith Rogers, MA, is the producer of the Public Health On Call podcast , an editor for Expert Insights , and the director of content strategy for the Johns Hopkins Bloomberg School of Public Health.

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Legalization of Recreational Use of Marijuana Research Paper

The use of marijuana can be viewed as one of the most debatable and controversial elements of the U.S. criminal justice agenda. Despite the fact that a range of regulations have been passed regarding the subject matter, the issue still remains rather complicated. At present, the use of medicinal marijuana is allowed in 23 States of America ( 23 legal medical marijuana states and DC , 2015); therefore, the struggle for making medicinal cannabis legal is far from being over.

A range of laws and regulations have shaped the legal policy regarding the use of marijuana over the past few decades (Benmaamar, 2014). However, when it comes to defining the groundbreaking court rulings that redefined the very approach towards marijuana use, one must mention the Jenks v. State of Florida (1991).

As it has been stressed above, the law has been modified significantly since its adoption in 1991; the changes that occurred to the specified regulation can be described as moving towards a more democratic interpretation of the subject matter, as the use of marijuana has been allowed in 23 states so far ( 23 legal medical marijuana states and DC , 2015). Moreover, the tendency in reinforcing the democratic concept in question seems to have been growing consistently; therefore, it is expected that the consumption of marijuana will be allowed in other states as well (Becker, 2015).

The role of the Supreme Court in the specified case boils down to stating the conditions, in which the prescription and the following use of marijuana by the patient, can be deemed as legitimate (Benmaamar, 2014). Particularly, the Supreme Court drove the line between the lawful use of marijuana and the illegal consumption thereof. In other words, the Supreme Court practically defines the very content of the regulation to be passed and affects the rights of the citizens in a direct way, either providing the residents of the United States with the corresponding rights or restricting their actions by setting specific limitations.

Needless to say, the specified regulation has brought a significant change to the current criminal justice policy regarding the use of marijuana. First and most obvious, the limitations for marijuana use were finally set, and tracking the instances of marijuana abuse became much easier. Additionally, the necessity to provide a prescription for purchasing the above-mentioned drug helped reduce the instances of drug abuse among the residents of the United States.

The ruling passed by the jury did not reflect the significance of technology in people’s lives at the time. The fact that medicinal marijuana will be provided to patients as long as they have the corresponding prescription was not shaped by technological advances of the time in any possible way. It would be wrong to assume, though, that the issue has been resolved completely. The changes in the way, in which people communicate, as well as the technology that they use in order to acquire the necessary information, may provide additional options for the people, who are willing to break the law. Thus, further reinforcement of the existing regulations will have to be carried out. Particularly, the issue of drones use as the means of stealing from cannabis farms (Withnall, 2014) will have to be addressed.

The changes made to the U.S. legal system in terms of marijuana use have clearly affected the social justice. Particularly, the fact that the rights of the people, who suffer tremendous pain and, therefore, have no other options but to use marijuana as a painkiller, finally were recognized deserves to be mentioned. Additionally, the specified legislation helped reduce the number of possible instances of drug peddling and drug abuse by some of the representatives of the U.S. healthcare services should also be brought up. In other words, the legislation described above created premises for representing the rights of patients along with the reinforcement of preventing measures against drug peddling.

The use of marijuana has been one of the most debatable issues in the United States, and the 1991 regulation passed as a result of the Jenks v. State of Florida (1991) court ruling allowed for solving some of the dilemmas, as well as provided a solid ground for promoting the rights of the people, who need medicinal marijuana for relieving the pain. In some way, the specified ruling can be considered a step forward in allowing the use of marijuana for the rest of the citizens of the United States provided that the target audience has reached the legal age.

It is assumed that further changes to the existing set of rules and regulations regarding the use of cannabis will be altered so that patients with terminal diseases, as well the patients, who are in unbearable pain, should be provided with more rights as far as the acquisition of recreational marijuana is concerned. Additionally, it is expected that the recreational use of marijuana that does not involve any treatment should also be considered legally. Despite the fact that the subject matter has already been viewed as a topical issue to be analyzed, the final approval of the idea of recreational use of marijuana is yet to be approved by the Supreme Court (Durkin, 2014).

Reference List

23 legal medical marijuana states and DC . (2015). Web.

Becker, S. (2015). 7 states on the verge of marijuana legalization. The CheatSheet . Web.

Benmaamar, R. (2014). Colorado: a first in the USA for legal sale of marijuana. Lancet Oncology, 15 (2): 55.

Durkin, A. (2014). Legalization of marijuana for non-medical use: Health, policy, socioeconomic, and nursing implications. J ournal of Psychosocial Nursing & Mental Health Services, 52 (9): 22–26.

Jenks v. State of Florida 582 So.2d 676 – Fla.App. 1 Dist. 1991.

Withnall, A. (2014). Criminals ‘using unmanned drones and infrared cameras to find illegal cannabis farms’ – and then steal from the growers. The Independent . Web.

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IvyPanda. (2022, April 16). Legalization of Recreational Use of Marijuana. https://ivypanda.com/essays/legalization-of-recreational-use-of-marijuana/

"Legalization of Recreational Use of Marijuana." IvyPanda , 16 Apr. 2022, ivypanda.com/essays/legalization-of-recreational-use-of-marijuana/.

IvyPanda . (2022) 'Legalization of Recreational Use of Marijuana'. 16 April.

IvyPanda . 2022. "Legalization of Recreational Use of Marijuana." April 16, 2022. https://ivypanda.com/essays/legalization-of-recreational-use-of-marijuana/.

1. IvyPanda . "Legalization of Recreational Use of Marijuana." April 16, 2022. https://ivypanda.com/essays/legalization-of-recreational-use-of-marijuana/.

Bibliography

IvyPanda . "Legalization of Recreational Use of Marijuana." April 16, 2022. https://ivypanda.com/essays/legalization-of-recreational-use-of-marijuana/.

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How Marijuana Legalization Changed Use in States

How has marijuana legalization changed the way Americans use it, and what does this mean for public health?

As of 2024, marijuana has become legalized for recreational use in 24 states, with 38 states permitting its use in medical contexts. However, as per the Drug Enforcement Administration, marijuana remains a Schedule I substance, in the same class as other drugs such as heroin, ecstasy and LSD.

This puts marijuana in a weird legal limbo: while it is available to buy and use in numerous states across America, its Schedule I classification has significantly impeded scientific research into its health effects and medical uses.

Between 2016 and 2022, the number of people enrolled in medical cannabis programs increased by more than 600 percent. However, these rises are not uniform across the country.

In a new study, published in the Annals of Internal Medicine , researchers from the University of Michigan Medical School and the Centers for Disease Control and Prevention found that although the overall number of medical marijuana users had risen, those living in states where marijuana is legal were much less likely to be enrolled in the programs.

"We had previously seen decreases in patient enrollment after non-medical adult use laws passed, but we were surprised at how dramatic some of the decreases were, especially in states like Arizona where the patient population dropped by over 50 percent from 2021 to 2022," Kevin Boehnke, an assistant professor of anesthesiology at the University of Michigan, told Newsweek .

"Practically, we see that enrolment in medical cannabis programs generally decreases after the passage of adult use cannabis laws. This warrants further study, but may be due to several factors, including licensing fees for medical use, inconvenience of appointments, and the ability to use nonmedical cannabis medically."

In other words, due to the restrictions and red tape you need to go through to acquire marijuana in a clinical context, many of those who seek to use marijuana for medical conditions choose to self-medicate because it is easier.

"Thus, much of the use and advice around medical cannabis occurs outside of the doctor's office, and may come from other sources like retailers," Boehnke said.

Boehnke added that the dramatic growth in medical cannabis licenses since 2016 shows the widespread demand for medical marijuana and highlights the need for policymakers to consider how best to regulate it to prioritize patient safety and public health.

"Medical cannabis isn't going anywhere, and it is important to figure out how best to effectively integrate cannabis into medical treatment given the widespread use," he said. "The remarkable growth in the number of people with medical cannabis licenses demonstrates the importance of conducting more and better research on the potential benefits and harms of cannabis for medical purposes."

"The continued criminalization of cannabis at the federal level through 'War on Drugs' policies is harmful and needs to change. These policies are a substantial barrier to effective research into the potential benefits and risks of cannabis."

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• v.42(3); 2017 Mar

Medicinal Cannabis: History, Pharmacology, And Implications for the Acute Care Setting

The authors review the historical use of medicinal cannabis and discuss the agent’s pharmacology and pharmacokinetics, select evidence on medicinal uses, and the implications of evolving regulations on the acute care hospital setting.

INTRODUCTION

Medicinal cannabis, or medicinal marijuana, is a therapy that has garnered much national attention in recent years. Controversies surrounding legal, ethical, and societal implications associated with use; safe administration, packaging, and dispensing; adverse health consequences and deaths attributed to marijuana intoxication; and therapeutic indications based on limited clinical data represent some of the complexities associated with this treatment. Marijuana is currently recognized by the U.S. Drug Enforcement Agency’s (DEA’s) Comprehensive Drug Abuse Prevention and Control Act (Controlled Substances Act) of 1970 as a Schedule I controlled substance, defined as having a high potential for abuse, no currently accepted medicinal use in treatment in the United States, and a lack of accepted safety data for use of the treatment under medical supervision. 1

Cannabis is the most commonly cultivated, trafficked, and abused illicit drug worldwide; according to the World Health Organization (WHO), marijuana consumption has an annual prevalence rate of approximately 147 million individuals or nearly 2.5% of the global population. 2 In 2014, approximately 22.2 million Americans 12 years of age or older reported current cannabis use, with 8.4% of this population reporting use within the previous month. 3 , 4 General cannabis use, both for recreational and medicinal purposes, has garnered increasing acceptance across the country as evidenced by legislative actions, ballot measures, and public opinion polls; an October 2016 Gallup poll on American’s views on legalizing cannabis indicated that 60% of the population surveyed believed the substance should be legalized. 5 Further, a recent Quinnipiac University poll concluded 54% of American voters surveyed would favor the legalization of cannabis without additional constraints, while 81% of respondents favored legalization of cannabis for medicinal purposes. 6 Limited data suggest that health care providers also may consider this therapy in certain circumstances. 7 – 9 In the United States, cannabis is approved for medicinal use in 28 states, the District of Columbia, Guam, and Puerto Rico as of January 2017. 10

The use and acceptance of medicinal cannabis continues to evolve, as shown by the growing number of states now permitting use for specific medical indications. The Food and Drug Administration (FDA) has considered how it might support the scientific rigor of medicinal cannabis claims, and the review of public data regarding safety and abuse potential is ongoing. 11 , 12 The purpose of this article is to review the historical significance of the use of medicinal cannabis and to discuss its pharmacology, pharmacokinetics, and select evidence on medicinal uses, as well as to describe the implications of evolving medicinal cannabis regulations and their effects on the acute care hospital setting.

HISTORICAL SIGNIFICANCE

Cannabis is a plant-based, or botanical, product with origins tracing back to the ancient world. Evidence suggesting its use more than 5,000 years ago in what is now Romania has been described extensively. 13 There is only one direct source of evidence (Δ 6 -tetrahydrocannabinol [Δ 6 -THC] in ashes) that cannabis was first used medicinally around 400 ad . 14 In the U.S., cannabis was widely utilized as a patent medicine during the 19th and early 20th centuries, described in the United States Pharmacopoeia for the first time in 1850. Federal restriction of cannabis use and cannabis sale first occurred in 1937 with the passage of the Marihuana Tax Act. 15 , 16 Subsequent to the act of 1937, cannabis was dropped from the United States Pharmacopoeia in 1942, with legal penalties for possession increasing in 1951 and 1956 with the enactment of the Boggs and Narcotic Control Acts, respectively, and prohibition under federal law occurring with the Controlled Substances Act of 1970. 1 , 17 , 18 Beyond criminalization, these legislative actions contributed to creating limitations on research by restricting procurement of cannabis for academic purposes.

In 1996, California became the first state to permit legal access to and use of botanical cannabis for medicinal purposes under physician supervision with the enactment of the Compassionate Use Act. As previously stated, as of January 1, 2017, 28 states as well as Washington, D.C., Guam, and Puerto Rico will have enacted legislation governing medicinal cannabis sale and distribution; 21 states and the District of Columbia will have decriminalized marijuana and eliminated prohibition for possession of small amounts, while eight states, including Alaska, California, Colorado, Maine, Massachusetts, Nevada, Oregon, and Washington, as well as the District of Columbia, will have legalized use of marijuana for adult recreation. 10 , 19

THE MEDICINAL CANNABIS DEBATE

As a Schedule I controlled substance with no accepted medicinal use, high abuse potential, concerns for dependence, and lack of accepted safety for use under medical supervision—along with a national stigma surrounding the potential harms and implication of cannabis use as a gateway drug to other substances—transitioning from a vilified substance to one with therapeutic merits has been controversial. The United States Pharmacopoeia and the FDA have considered the complexities of regulating this plant-based therapy, including the numerous compounds and complex interactions between substances in this product, and how it might fit into the current regulatory framework of drugs in United States. 11 , 12 , 17

The emergence of interest in botanical medicinal cannabis is thought by many to be a collateral effect of the opioid abuse epidemic; public perception surrounding the use of medicinal cannabis suggests that this plant-based therapy is viewed as not much different than a botanical drug product or supplement used for health or relief of symptoms if disease persists. Like some herbal preparations or supplements, however, medicinal cannabis may similarly pose health risks associated with its use, including psychoactive, intoxicating, and impairing effects, which have not been completely elucidated through clinical trials. Proponents argue that there is evidence to support botanical medicinal cannabis in the treatment of a variety of conditions, particularly when symptoms are refractory to other therapies; that beneficial cannabinoids exist, as evidenced by single-entity agents derived from cannabis containing the compounds THC and cannabidiol (CBD); that cannabis is relatively safe, with few deaths reported from use; that therapy is self-titratable by the patient; and that therapy is relatively inexpensive compared with pharmaceutical agents. 20 – 22 Opponents of medicinal cannabis use argue, in part, that well-designed randomized trials to confirm benefits and harms are lacking; that it has not been subject to the rigors of the FDA approval process; that standardization in potency or quantity of pharmacologically active constituents is absent; that adverse health effects relate not only to smoking cannabis but to unmasking mental health disorders, impairing coordination, and affecting judgment; that standardization does not exist for product packaging and controls to prevent inadvertent use by minors or pets; that there is a potential for dependence, addiction, and abuse; and that costs pose a potential burden. 23 – 25

Regardless of personal views and perceptions, to deny or disregard the implications of use of this substance on patient health and the infrastructure of the health care system is irresponsible; clinicians must be aware of these implications and informed about how this therapy may influence practice in a variety of health care settings, including acute care.

PHARMACOLOGY

Endocannabinoids (eCBs) and their receptors are found throughout the human body: nervous system, internal organs, connective tissues, glands, and immune cells. The eCB system has a homeostatic role, having been characterized as “eat, sleep, relax, forget, and protect.” 26 It is known that eCBs have a role in the pathology of many disorders while also serving a protective function in certain medical conditions. 27 It has been proposed that migraine, fibromyalgia, irritable bowel syndrome, and related conditions represent clinical eCB deficiency syndromes (CEDS). Deficiencies in eCB signaling could be also involved in the pathogenesis of depression. In human studies, eCB system deficiencies have been implicated in schizophrenia, multiple sclerosis (MS), Huntington’s disease, Parkinson’s disease, anorexia, chronic motion sickness, and failure to thrive in infants. 28

The eCB system represents a microcosm of psycho-neuroimmunology or “mind–body” medicine. The eCB system consists of receptors, endogenous ligands, and ligand metabolic enzymes. A variety of physiological processes occur when cannabinoid receptors are stimulated. Cannabinoid receptor type 1 (CB 1 ) is the most abundant G-protein–coupled receptor. It is expressed in the central nervous system, with particularly dense expression in (ranked in order): the substantia nigra, globus pallidus, hippocampus, cerebral cortex, putamen, caudate, cerebellum, and amygdala. CB 1 is also expressed in non-neuronal cells, such as adipocytes and hepatocytes, connective and musculoskeletal tissues, and the gonads. CB 2 is principally associated with cells governing immune function, although it may also be expressed in the central nervous system.

The most well-known eCB ligands are N-arachidonyl-ethanolamide (anandamide or AEA) and sn-2-arachidonoyl-glycerol (2-AG). AEA and 2-AG are released upon demand from cell membrane phospholipid precursors. This “classic” eCB system has expanded with the discovery of secondary receptors, ligands, and ligand metabolic enzymes. For example, AEA, 2-AG, N-arachidonoyl glycine (NAGly), and the phytocannabinoids Δ 9 -THC and CBD may also serve, to different extents, as ligands at GPR55, GPR18, GPR119, and several transient receptor potential ion channels (e.g., TRPV1, TRPV2, TRPA1, TRPM8) that have actions similar to capsaicin. 28 The effects of AEA and 2-AG can be enhanced by “entourage compounds” that inhibit their hydrolysis via substrate competition, and thereby prolong their action through synergy and augmentation. Entourage compounds include N-palmitylethanolamide (PEA), N-oleoylethanolamide (SEA), and cis-9-octadecenoamide (OEA or oleamide) and may represent a novel route for molecular regulation of endogenous cannabinoid activity. 29

Additional noncannabinoid targets are also linked to cannabis. G-protein–coupled receptors provide noncompetitive inhibition at mu and delta opioid receptors as well as norepinephrine, dopamine, and serotonin. Ligand-gated ion channels create allosteric antagonism at serotonin and nicotinic receptors, and enhance activation of glycine receptors. Inhibition of calcium, potassium, and sodium channels by noncompetitive antagonism occurs at nonspecific ion channels and activation of PPARα and PPARγ at the peroxisome proliferator-activated receptors is influenced by AEA. 30

THC is known to be the major psychoactive component of cannabis mediated by activation of the CB 1 receptors in the central nervous system; however, this very mechanism limits its use due to untoward adverse effects. It is now accepted that other phytocannabinoids with weak or no psychoactivity have promise as therapeutic agents in humans. The cannabinoid that has sparked the most interest as a nonpsychoactive component is CBD. 31 Unlike THC, CBD elicits its pharmacological effects without exerting any significant intrinsic activity on CB 1 and CB 2 receptors. Several activities give CBD a high potential for therapeutic use, including antiepileptic, anxiolytic, antipsychotic, anti-inflammatory, and neuroprotective effects. CBD in combination with THC has received regulatory approvals in several European countries and is under study in registered trials with the FDA. And, some states have passed legislation to allow for the use of majority CBD preparations of cannabis for certain pathological conditions, despite lack of standardization of CBD content and optimal route of administration for effect. 32 Specific applications of CBD have recently emerged in pain (chronic and neuropathic), diabetes, cancer, and neurodegenerative diseases, such as Huntington’s disease. Animal studies indicate that a high dose of CBD inhibits the effects of lower doses of THC. Moreover, clinical studies suggest that oral or oromucosal CBD may prolong and/or intensify the effects of THC. Finally, preliminary clinical trials suggest that high-dose oral CBD (150–600 mg per day) may exert a therapeutic effect for epilepsy, insomnia, and social anxiety disorder. Nonetheless, such doses of CBD have also been shown to cause sedation. 33

PHARMACOKINETICS AND ADMINISTRATION

The three most common methods of administration are inhalation via smoking, inhalation via vaporization, and ingestion of edible products. The method of administration can impact the onset, intensity, and duration of psychoactive effects; effects on organ systems; and the addictive potential and negative consequences associated with use. 34

Cannabinoid pharmacokinetic research has been challenging; low analyte concentrations, rapid and extensive metabolism, and physicochemical characteristics hinder the separation of compounds of interest from biological matrices and from each other. The net effect is lower drug recovery due to adsorption of compounds of interest to multiple surfaces. 35 The primary psychoactive constituent of marijuana—Δ 9 -THC—is rapidly transferred from lungs to blood during smoking. In a randomized controlled trial conducted by Huestis and colleagues, THC was detected in plasma immediately after the first inhalation of marijuana smoke, attesting to the efficient absorption of THC from the lungs. THC levels rose rapidly and peaked prior to the end of smoking. 36 Although smoking is the most common cannabis administration route, the use of vaporization is increasing rapidly. Vaporization provides effects similar to smoking while reducing exposure to the byproducts of combustion and possible carcinogens and decreasing adverse respiratory syndromes. THC is highly lipophilic, distributing rapidly to highly perfused tissues and later to fat. 37 A trial of 11 healthy subjects administered Δ 9 -THC intravenously, by smoking, and by mouth demonstrated that plasma profiles of THC after smoking and intravenous injection were similar, whereas plasma levels after oral doses were low and irregular, indicating slow and erratic absorption. The time courses of plasma concentrations and clinical “high” were of the same order for intravenous injection and smoking, with prompt onset and steady decline over a four-hour period. After oral THC, the onset of clinical effects was slower and lasted longer, but effects occurred at much lower plasma concentrations than they did after the other two methods of administration. 38

Cannabinoids are usually inhaled or taken orally; the rectal route, sublingual administration, transdermal delivery, eye drops, and aerosols have been used in only a few studies and are of little relevance in practice today. The pharmacokinetics of THC vary as a function of its route of administration. Inhalation of THC causes a maximum plasma concentration within minutes and psychotropic effects within seconds to a few minutes. These effects reach their maximum after 15 to 30 minutes and taper off within two to three hours. Following oral ingestion, psychotropic effects manifest within 30 to 90 minutes, reach their maximum effect after two to three hours, and last for about four to 12 hours, depending on the dose. 39

Within the shifting legal landscape of medical cannabis, different methods of cannabis administration have important public health implications. A survey using data from Qualtrics and Facebook showed that individuals in states with medical cannabis laws had a significantly higher likelihood of ever having used the substance with a history of vaporizing marijuana (odds ratio [OR], 2.04; 99% confidence interval [CI], 1.62–2.58) and a history of oral administration of edible marijuana (OR, 1.78; 99% CI, 1.39–2.26) than those in states without such laws. Longer duration of medical cannabis status and higher dispensary density were also significantly associated with use of vaporized and edible forms of marijuana. Medical cannabis laws are related to state-level patterns of utilization of alternative methods of cannabis administration. 34

DRUG INTERACTIONS

Metabolic and pharmacodynamic interactions may exist between medical cannabis and other pharmaceuticals. Quantification of the in vitro metabolism of exogenous cannabinoids, including THC, CBD, and cannabinol (CBN), indicates hepatic cytochrome 450 (CYP450) isoenzymes 2C9 and 3A4 play a significant role in the primary metabolism of THC and CBN, whereas 2C19 and 3A4 and may be responsible for metabolism of CBD. 40 Limited clinical trials quantifying the effect of the exogenous cannabinoids on the metabolism of other medications exist; however, drug interaction data may be gleaned from the prescribing information from cannabinoid-derived pharmaceutical products such as Sativex (GW Pharmaceuticals, United Kingdom) and dronabinol (Marinol, AbbVie [United States]). 41 , 42 Concomitant administration of ketoconazole with oromucosal cannabis extract containing THC and CBD resulted in an increase in the maximum serum concentration and area under the curve for both THC and CBD by 1.2-fold to 1.8-fold and twofold, respectively; coadministration of rifampin is associated with a reduction in THC and CBD levels. 40 , 41 In clinical trials, dronabinol use was not associated with clinically significant drug interactions, although additive pharmacodynamic effects are possible when it is coadministered with other agents having similar physiological effects (e.g., sedatives, alcohol, and antihistamines may increase sedation; tricyclic antidepressants, stimulants, and sympathomimetics may increase tachycardia). 41 Additionally, smoking cannabis may increase theophylline metabolism, as is also seen after smoking tobacco. 40 , 42

ADVERSE EFFECTS

Much of what is known about the adverse effects of medicinal cannabis comes from studies of recreational users of marijuana. 43 Short-term use of cannabis has led to impaired short-term memory; impaired motor coordination; altered judgment; and paranoia or psychosis at high doses. 44 Long-term or heavy use of cannabis, especially in individuals who begin using as adolescents, has lead to addiction; altered brain development; cognitive impairment; poor educational outcomes (e.g., dropping out of school); and diminished life satisfaction. 45 Long-term or heavy use of cannabis is also associated with chronic bronchitis and an increased risk of chronic psychosis-related health disorders, including schizophrenia and variants of depression, in persons with a predisposition to such disorders. 46 – 48 Vascular conditions, including myocardial infarction, stroke, and transient ischemic attack, have also been associated with cannabis use. 49 – 51 The use of cannabis for management of symptoms in neurodegenerative diseases, such as Parkinson’s, Alzheimer’s, and MS, has provided data related to impaired cognition in these individuals. 52 , 53

A systematic review of published trials on the use of medical cannabinoids over a 40-year period was conducted to quantify adverse effects of this therapy. 54 A total of 31 studies evaluating the use of medicinal cannabis, including 23 randomized controlled trials and eight observational studies, was included. In the randomized trials, the median duration of cannabinoid exposure was two weeks, with a range between eight hours and 12 months. Of patients assigned to active treatment in these trials, a total of 4,779 adverse effects were reported; 96.6% (4,615) of these were not deemed by authors to be serious. The most common serious adverse effects included relapsing MS (9.1%; 15 events), vomiting (9.8%; 16 events), and urinary tract infections (9.1%; 15 events). No significant differences in the rates of serious adverse events between individuals receiving medical cannabis and controls were identified (relative risk, 1.04; 95% CI, 0.78–1.39). The most commonly reported non-serious adverse event was dizziness, with an occurrence rate of 15.5% (714 events) among people exposed to cannabinoids. 54

Other negative adverse effects reported with acute cannabis use include hyperemesis syndrome, impaired coordination and performance, anxiety, suicidal ideations or tendencies, and psychotic symptoms, whereas chronic effects may include mood disturbances, exacerbation of psychotic disorders, cannabis use disorders, withdrawal syndrome, and neurocognitive impairments, as well as cardiovascular and respiratory conditions. 52 Long-term studies evaluating adverse effects of chronic medicinal cannabis use are needed to conclusively evaluate the risks when used for an extended period of time.

MEDICINAL USES

Cannabis and cannabinoid agents are widely used to alleviate symptoms or treat disease, but their efficacy for specific indications is not well established. For chronic pain, the analgesic effect remains unclear. A systematic review of randomized controlled trials was conducted examining cannabinoids in the treatment of chronic noncancer pain, including smoked cannabis, oromucosal extracts of cannabis-based medicine, nabilone, dronabinol, and a novel THC analogue. 55 Pain conditions included neuropathic pain, fibromyalgia, rheumatoid arthritis, and mixed chronic pain. Fifteen of the 18 included trials demonstrated a significant analgesic effect of cannabinoids compared with placebo. Cannabinoid use was generally well tolerated; adverse effects most commonly reported were mild to moderate in severity. Overall, evidence suggests that cannabinoids are safe and moderately effective in neuropathic pain with preliminary evidence of efficacy in fibromyalgia and rheumatoid arthritis. 55

While there is not enough evidence to suggest routine use of medicinal cannabis for alleviating chemotherapy-related nausea and vomiting by national or international cancer societies, therapeutic agents based on THC (e.g., dronabinol) have been approved for use as an antiemetic in the United States for a number of years. Only recently has the efficacy and safety of cannabis-based medicines in managing nausea and vomiting due to chemotherapy been evaluated. In a review of 23 randomized, controlled trials, patients who received cannabis-based products experienced less nausea and vomiting than subjects who received placebo. 56 The proportion of people experiencing nausea and vomiting who received cannabis-based products was similar to those receiving conventional antiemetics. Subjects using cannabis-based products experienced side effects such as “feeling high,” dizziness, sedation, and dysphoria and dropped out of the studies at a higher rate due to adverse effects compared with participants receiving either placebo or conventional antiemetics. In crossover trials in which patients received cannabis-based products and conventional antiemetics, patients preferred the cannabis-based medicines. Cannabis-based medications may be useful for treating chemotherapy-induced nausea and vomiting that responds poorly to conventional antiemetics. However, the trials produced low to moderate quality evidence and reflected chemotherapy agents and antiemetics that were available in the 1980s and 1990s.

With regard to the management of neurological disorders, including epilepsy and MS, a Cochrane review of four clinical trials that included 48 epileptic patients using CBD as an adjunct treatment to other antiepileptic medications concluded that there were no serious adverse effects associated with CBD use but that no reliable conclusions on the efficacy and safety of the therapy can be drawn from this limited evidence. 57 The American Academy of Neurology (AAN) has issued a Summary of Systematic Reviews for Clinicians that indicates oral cannabis extract is effective for reducing patient-reported spasticity scores and central pain or painful spasms when used for MS. 58 THC is probably effective for reducing patient-reported spasticity scores but is likely ineffective for reducing objective measures of spasticity at 15 weeks, the AAN found; there is limited evidence to support the use of cannabis extracts for treatment of Huntington’s disease, levodopa-induced dyskinesias in patients with Parkinson’s disease, or reducing tic severity in Tourette’s. 58

In older patients, medical cannabinoids have shown no efficacy on dyskinesia, breathlessness, and chemotherapy-induced nausea and vomiting. Some evidence has shown that THC might be useful in treatment of anorexia and behavioral symptoms in patients with dementia. The most common adverse events reported during cannabinoid treatment in older adults were sedation-like symptoms. 59

Despite limited clinical evidence, a number of medical conditions and associated symptoms have been approved by state legislatures as qualifying conditions for medicinal cannabis use. Table 1 contains a summary of medicinal cannabis indications by state, including select disease states and qualifying debilitating medical conditions or symptoms. 10 , 60 , 61 The most common conditions accepted by states that allow medicinal cannabis relate to relief of the symptoms of cancer, glaucoma, human immunodeficiency virus/acquired immunodeficiency syndrome, and MS. A total of 28 states, the District of Columbia, Guam, and Puerto Rico now allow comprehensive public medical marijuana and cannabis programs. 10 The National Conference of State Legislatures uses the following criteria to determine if a program is comprehensive:

Medicinal Cannabis Indications for Use by State 10 , 60 , 61

1 = State law additionally covers any condition where treatment with medical cannabis would be beneficial, according to the patient’s physician

2 = State law covers any severe condition refractory to other medical treatment

3 = Additional restrictions on the use for this indication exist in this state

4 = State law requires providers to certify the existence of a qualifying disease and symptom

HIV/AIDS = human immunodeficiency virus/acquired immunodeficiency syndrome

Table adapted with permission from the Marijuana Policy Project; 60 table is not all-encompassing and other medical conditions for use may exist. The reader should refer to individual state laws regarding medicinal cannabis for specific details of approved conditions for use. In addition, states may permit the addition of approved indications; list is subject to change.

• Protection from criminal penalties for using marijuana for a medical purpose;
• Access to marijuana through home cultivation, dispensaries, or some other system that is likely to be implemented;
• Allows a variety of strains, including more than those labeled as “low THC;” and
• Allows either smoking or vaporization of some kind of marijuana products, plant material, or extract.

Some of the most common policy questions regarding medical cannabis now include how to regulate its recommendation and indications for use; dispensing, including quality and standardization of cultivars or strains, labeling, packaging, and role of the pharmacist or health care professional in education or administration; and registration of approved patients and providers.

REGULATORY IMPLICATIONS OF MEDICINAL CANNABIS

The regulation of cannabis therapy is complex and unique; possession, cultivation, and distribution of this substance, regardless of purpose, remain illegal at the federal level, while states that permit medicinal cannabis use have established individual laws and restrictions on the sale of cannabis for medical purposes. In a 2013 U.S. Department of Justice memorandum to all U.S. attorneys, Deputy Attorney General James M. Cole noted that despite the enactment of state laws authorizing marijuana production and sale having a regulatory structure that is counter to the usual joint efforts of federal authorities working together with local jurisdictions, prosecution of individuals cultivating and distributing marijuana to seriously ill individuals for medicinal purpose has not been identified as a federal priority. 62

There are, however, other regulatory implications to consider based on the federal restriction of cannabis. Physicians cannot legally “prescribe” medicinal cannabis therapy, given its Schedule I classification, but rather in accordance with state laws may certify or recommend patients for treatment. Medical cannabis expenses are not reimbursable through government medical assistance programs or private health insurers. As previously described, the Schedule I listing of cannabis according to federal law and DEA regulations has led to difficulties in access for research purposes; nonpractitioner researchers can register with the DEA more easily to study substances in Schedules II–V compared with Schedule I substances. 63 Beyond issues related to procurement of the substance for research purposes, other limitations in cannabis research also exist. For example, the Center for Medicinal Cannabis Research at the University of California–San Diego had access to funding, marijuana at different THC levels, and approval for a number of clinical research trials, and yet failed to recruit an adequate number of patients to conduct five major trials, which were subsequently canceled. 64 Unforeseen factors, including the prohibition of driving during the clinical trials, deterred patients from trial enrollment. The limited availability of clinical research to support or refute therapeutic claims and indications for use of cannabis for medicinal purposes has frequently left both state legislative authorities and clinicians to rely on anecdotal evidence, which has not been subjected to the same rigors of peer review and scrutiny as well-conducted, randomized trials, to validate the safety and efficacy of medicinal cannabis therapy. Furthermore, although individual single-entity pharmaceutical medications, such as dronabinol, have been isolated, evaluated, and approved for use by the FDA, a plant cannot be patented and mass produced by a corporate entity. 65 Despite this limitation, some corporations, including GW Pharmaceuticals, are mass producing cannabis plants and extracting complex mixtures or single cannabinoids for clinical trials. 65 The complex pharmacology related to the numerous substances and interactions among chemicals in the cannabis plant coupled with environmental variables in cultivation further complicate regulation, standardization, purity, and potency as a botanical drug product.

RELEVANCE TO HOSPITAL PRACTITIONERS

Although the public has largely accepted medicinal cannabis therapy as having a benefit when used under a provider’s supervision, the implications of the use of this substance when patients transition into the acute care setting are additionally complex and multifaceted. The Schedule I designation of cannabis causes hospitals and other care settings that receive federal funding, either through Medicare reimbursement or other federal grants or programs, to pause to consider the potential for loss of these funds should the federal government intercede and take action if patients are permitted to use this therapy on campus. Similarly, licensed practitioners registered to certify patients for state medicinal cannabis programs may have comparable concerns regarding jeopardizing their federal DEA registrations and ability to prescribe other controlled substances as well as jeopardizing Medicare reimbursements. In 2009, U.S. Attorney General Eric Holder recommended that enforcement of federal marijuana laws not be a priority in states that have enacted medicinal cannabis programs and are enforcing the rules and regulations of such a program; despite this, concerns persist.

The argument for or against the use of medicinal cannabis in the acute care setting encompasses both legal and ethical considerations, with the argument against use perhaps seeming obvious on its surface. States adopting medical cannabis laws may advise patients to utilize the therapy only in their own residence and not to transport the substances unless absolutely necessary. 66 Further, many acute care institutions have policies prohibiting smoking on facility grounds, thus restricting the smoking of cannabis, regardless of purpose or indication. Of note, several Canadian hospitals, including Montreal’s Jewish General Hospital and Quebec’s Centre Hospitalier Universitaire de Sherbrooke, have permitted inpatient cannabis use via vaporization; the pharmacy departments of the respective institutions control and dispense cannabis much like opioids for pain. Canada has adopted national regulations to control and standardize dried cannabis for medical use. 67 , 68 There are complicated logistics for self-administration of medicinal cannabis by the patient or caregiver; in particular, many hospitals have policies on self-administration of medicines that permit patients to use their own medications only after identification and labeling by pharmacy personnel. The argument can be made that an herb- or plant-based entity cannot be identified by pharmacy personnel as is commonly done for traditional medicines, although medicinal cannabis dispensed through state programs must be labeled in accordance with state laws. Dispensing and storage concerns, including an evaluation of where and how this product should be stored (e.g., within the pharmacy department and treated as a controlled substance, by security personnel, or with the patient); who should administer it, and implications or violations of federal law by those administering treatment; what pharmaceutical preparations should be permitted (e.g., smoked, vaporized, edible); and how it should be charted in the medical record represent other logistical concerns. Inpatient use of medicinal cannabis also carries implications for nursing and medical staff members. The therapy cannot be prescribed, and states may require physicians authorizing patient use to be registered with local programs. In a transition into the acute care setting from the community setting, a different clinician who is not registered could be responsible for the patient’s care; that clinician would be restricted in ordering continuation of therapy.

Despite the complexities in the logistics of continuing medicinal cannabis in the acute care setting, proponents of palliative care and continuity of care argue that prohibiting medicinal cannabis use disrupts treatment of chronic and debilitating medical conditions. Patients have been denied this therapy during acute care hospitalizations for reasons stated above. 69 Permission to use medicinal cannabis in the acute care setting may be dependent on state legislation and restrictions imposed by such laws. Legislation in Minnesota, as one example, has been amended to permit hospitals as facilities that can dispense and control cannabis use; similar legislative actions protecting nurses from criminal, civil, or disciplinary action when administering medical cannabis to qualified patients have been enacted in Connecticut and Maine. 70 – 73 Proposed legislation to remove restrictions on the certification of patients to receive medicinal cannabis by doctors at the Department of Veterans Affairs was struck down in June; prohibitions continue on the use of this therapy even in facilities located in states permitting medicinal cannabis use. 74

Despite lingering controversy, use of botanical cannabis for medicinal purposes represents the revival of a plant with historical significance reemerging in present day health care. Legislation governing use of medicinal cannabis continues to evolve rapidly, necessitating that pharmacists and other clinicians keep abreast of new or changing state regulations and institutional implications. Ultimately, as the medicinal cannabis landscape continues to evolve, hospitals, acute care facilities, clinics, hospices, and long-term care centers need to consider the implications, address logistical concerns, and explore the feasibility of permitting patient access to this treatment. Whether national policy—particularly with a new presidential administration—will offer some clarity or further complicate regulation of this treatment remains to be seen.

Disclosures: The authors report no commercial or financial interests in regard to this article.