Marijuana liberalization policies: why we can’t learn much from policy still in motion

Proximity to Cannabis Retailers and Recent Cannabis Use among a Diverse Sample of California Adolescents

Background: As of May 2023, 23 states and Washington, DC have legalized the sale of cannabis for adults aged 21+, and 38 states, three territories, and D.C. have legalized medical cannabis. Exposure to cannabis retailers could increase adolescent cannabis use. Few studies have examined the impact of residential proximity to cannabis retailers on adolescent cannabis use, and previous findings are inconsistent. Methods: This study examined associations between proximity to cannabis retailers and past 30-day cannabis use. Data were from Project Cal Teens, a statewide survey of California adolescents regarding cannabis-related opinions/behaviors (N = 1406, mean age = 15.5 years, 48% female, 38% Hispanic/Latinx, 33% White, 15% Asian/Pacific Islander, 10% Black/African American, 5% Other/Multiracial). Participants were recruited via schools/social media in 2018-2020. Results: For every additional 5 driving miles to the nearest cannabis retailer, the risk of past 30-day cannabis use was reduced by 3.6% [IRR: 0.964; 95% CI: 0.935-0.994]. For every additional 5 miles from a licensed retailer, the risk of past 30-day cannabis use was reduced by 4.3% [IRR: 0.957; 95% CI: 0.926-0.989]. Interaction analyses revealed that among Hispanic/Latinx students, every 5 miles from a licensed retailer was associated with an 11.9% reduction in the risk of past 30-day cannabis use [IRR: 0.881; 95% CI: 0.820-0.945]. Conclusions: As the number of cannabis retailers in the U.S. increases with the continued legalization of adult cannabis use, research examining the effects of these policies on underage use is crucial. Interventions could include enforcement of zoning laws in/near residential areas to reduce accessibility of adolescents to cannabis retailers.

Cannabis Policy and Consumption: Taking into account Substitution Effects

Background: Previous studies examining the cannabis-alcohol substitution effect have found that medical cannabis policies may result in substituting the use of cannabis in place of alcohol use. Objectives: This study adds to the literature on cannabis-alcohol substitution by analyzing the effect of decriminalization, medicinal cannabis, and adult-use legalization cannabis policies (2002-2019) on cannabis and alcohol use and substance substitution for all 50 states and the District of Columbia (N=867). Results: Results support the notion that liberalized cannabis policies can increase the prevalence of cannabis use. An adult-use legalization specific analysis yielded findings suggesting a complex and heterogenous effect of such laws on cannabis-alcohol complementation. Conclusion: Given the lack of clarity and heterogenous effects of cannabis laws, policy makers should carefully take into consideration the benefits of medical cannabis laws, along with the risks of decriminalization and adult-use legalization.

Deterrence effect of penalties upon adolescent cannabis use

OBJECTIVE

Penalties are used in an effort to curtail drug use by citizens in most societies. There are growing calls for a reduction or elimination of such penalties. Deterrence theory suggests that use should increase if penalties reduce and vice versa. We sought to examine the relationship between changes to penalties for drug possession and adolescent cannabis use.

METHOD

Ten instances of penalty change occurred in Europe between 2000 and 2014, seven of which involved penalty reduction and three involved penalty increase. We conducted a secondary analysis of a series of cross-sectional surveys of 15-16-year-old school children, the ESPAD surveys, which are conducted every four years. We focused on past month cannabis use. We anticipated that an eight-year time span before and after each penalty change would yield two data points either side of the change. A simple trend line was fitted to the data points for each country.

RESULTS

In eight cases, the trend slope in past month cannabis use was in the direction predicted by deterrence theory, the two exceptions being the UK policy changes. Using the principals of binomial distributions, the likelihood of this happening by chance is 56/1024 = 0.05. The median change in the baseline prevalence rate was by 21%.

CONCLUSIONS

The science seems far from settled on this issue. There remains a distinct possibility that reducing penalties could contribute to small increases in adolescent cannabis use and consequently increase cannabis-related harms. This possibility should be considered in any political decision-making influencing drug policy changes.

Patterns of Cannabis and Alcohol Co-Use: Substitution Versus Complementary Effects

PURPOSE

The purpose of this review is to discuss the literature regarding the concurrent use (co-use) of alcohol and cannabis and competing hypotheses as to whether cannabis acts as a substitute for (i.e., replacing the effects of alcohol, resulting in decreased use) or a complement to (i.e., used to enhance the effects of alcohol, resulting in increased use) alcohol. The impact of cannabis use on alcohol-related outcomes has received increased attention in the wake of ongoing legalization of cannabis for both medical and recreational purposes. Evidence for both hypotheses exists in the literature across a broad range of data collection methods and samples and is carefully reviewed here. In addition, various mechanisms by which cannabis may act as an alcohol substitute or complement are explored in depth with the goal of better understanding equivocal findings.

SEARCH METHODS

This review includes articles that were identified from a search for studies on alcohol and cannabis co-use, with a specific focus on studies exploring complementary versus substitution aspects of co-use. Search terms were included in Google Scholar, PsycINFO, MEDLINE, and Web of Science. Eligible studies were those that measured alcohol and cannabis co-use in human samples in laboratory, survey, or ecological momentary assessment studies, or that directly referenced substitution or complementary patterns of use.

SEARCH RESULTS

Search results returned 650 articles, with 95 meeting inclusion criteria.

DISCUSSION AND CONCLUSIONS

Results of this review reveal compelling evidence for both substitution and complementary effects, suggesting nuanced yet significant distinctions across different populations examined in these studies. Several mechanisms for the impact of cannabis use on alcohol-related outcomes are identified, including patterns and context of co-use, timing and order of use, cannabinoid formulation, pharmacokinetic interactions, and user characteristics (including diagnostic status), all of which may influence substitution versus complementary effects. This review will inform future research studies examining this topic in both clinical and community samples and aid in the development of treatment and prevention efforts targeting those populations most vulnerable to negative consequences of co-use. Finally, this review highlights the need for additional research in more diverse samples and the use of mixed-methods designs to examine both pharmacological and contextual influences on co-use.

Factors Associated With Cannabis Use During the Reproductive Cycle: A Retrospective Cross-Sectional Study of Women in States With Recreational and Medical Cannabis Legalization

INTRODUCTION

Passage of cannabis laws may impact cannabis use and the use of other substances. The suggested association is of particular concern in pregnant women where exposure to substances can cause harm to both the pregnant woman and fetus. The present study contributes to the minimal literature on factors associated with cannabis use during the preconception, prenatal, and postpartum periods including state legalization status, concurrent use of tobacco and e-cigarettes and adequacy of prenatal care.

METHODS

We conducted a cross-sectional analysis using combined survey data from the 2016-2018 Pregnancy Risk Assessment Monitoring System (PRAMS) collected from 36,391 women. Logistic regression was used to estimate the impact of state-legalization, adequacy of prenatal care, and other substance use on cannabis use during the preconception, prenatal, and post-partum periods.

RESULTS

In the preconception model, residence in a recreationally legal state (OR: 2.37; 95% CI, 2.04-2.75) or medically legal state (OR:3.32; 95% CI, 2.90-3.80) compared to a non-legal state was associated with higher odds of cannabis use. In the prenatal model, residence in a recreationally legal state was associated with higher odds of cannabis use (OR: 1.51; 95% CI, 1.29-1.79) whereas there was no association with residence in a medically legal state. Tobacco use including e-cigarettes and moderate prenatal alcohol use were also significantly associated with cannabis use.

CONCLUSION

Recreational cannabis legalization is associated with the use of cannabis prior to, during, and after pregnancy. Renewed clinical and policy efforts may be warranted to update prenatal substance use prevention programs, educational campaigns, and provider education as cannabis legalization evolves.

Green Hope: Perspectives on Cannabis from People who Use Opioids

While states are implementing policies to legalize cannabis for medical or recreational purposes, it remains a Schedule 1 controlled substance with no medical uses according to US federal law. The perception of cannabis depends on social and cultural norms that impact political institutions involved in implementing policy. Because of negative social constructions, such as the "gateway hypothesis," legalization of cannabis has been slow and contentious. Recent studies suggest that cannabis can help combat the opioid epidemic. This paper fills a gap in our understanding of how cannabis is viewed by people who are actively misusing opioids and not in treatment. Using ethnographic methods to recruit participants living in a state that legalized cannabis and a state where cannabis was illegal, survey and interview data were analyzed informed by a social constructionist lens. Findings from their "insider perspective" suggest that for some people struggling with problematic opioid use, cannabis can be beneficial.

Dual trajectories of cannabis and alcohol use among young adults in a state with legal nonmedical cannabis

BACKGROUND

Understanding the nature of the association between cannabis and alcohol use within individuals over time in the era of legalized cannabis is of crucial importance for assessing the public health consequences of increasing cannabis use. An important unanswered question is whether cannabis and alcohol use substitute for one another. Specifically, is greater use of one substance associated with less use of the other substance (i.e., a negative association) or are the substances complementary and their association positive?

METHODS

We used 24 consecutive months of data on a young adult sample (n = 774; 56% female, age 18-25 during the study) who drank alcohol in the year prior to enrollment. The sample was recruited in Washington State in 2015/2016 (after legalization of nonmedical cannabis) using media advertisements and community flyers and outreach. Using parallel process latent growth curve models, we assessed three types of association between cannabis and alcohol use across the 24-month period: (1) an association between average levels of cannabis and alcohol use; (2) an association between rates of change in cannabis and alcohol use; and (3) correlations between shorter-term deviations/fluctuations off of longer-term trajectories of level and change in cannabis and alcohol use.

RESULTS

We found a positive association between the average frequency of cannabis and alcohol use; individuals who used cannabis more frequently on average also drank alcohol more frequently on average. Change over time in cannabis use was positively associated with change in alcohol use. There was also a contemporaneous positive association between fluctuations in cannabis and alcohol use.

CONCLUSIONS

Overall, we found no evidence of substitution. Rather, the results suggest a complementary relationship between cannabis and alcohol use, such that the use of cannabis and alcohol rises and falls together.

Beyond the high: Mapping patterns of use and motives for use of cannabis as medicine

Background:

In Denmark the boundaries between cannabis as an illicit drug and licit medicine have shifted rapidly in recent years, affecting also policy. However, the vast majority of Danes, who use cannabis as medicine (CaM) continue to rely on the unregulated market for supply. This study explores patterns of use and motives for use of CaM in Denmark.

Methods:

An anonymous online survey was made available to a convenience sample of users of CaM from July 14, 2018 to November 1, 2018. Participants were recruited through patient organisations, social and public media, and the illegal open cannabis market.

Results:

Of the final sample (n = 3,021), a majority were women (62.6%) and the mean age was 49 years. Most had no prescription for CaM (90.9%), a majority had no or limited previous experience with recreational cannabis use (63.9%), and had used CaM for two years or less (65.0%). The most common form of intake was oil (56.8%) followed by smoke (24.0%). CBD oil (65.0%) was used more than hash, pot or skunk (36.2%). Most frequent conditions treated were chronic pain (32.0%), sleep disturbances (27.5%), stress (23.7%), osteoarthritis (22.7%), anxiety (19.6%), and depression (19.6%). Overall, users experienced CaM to be effective in managing somatic and mental health conditions and reported relatively few side-effects. CBD oil only users were more likely to be women, older, have limited recreational experience and have initiated use recently.

Conclusions:

A new user group has emerged in Denmark that, for the most part, use illegally sourced CaM to treat a broad range of somatic and mental health conditions, often with experienced effect and relatively low level of side-effects. The prevalent use of low-potency CBD oil indicates an interest in effects beyond the high normally associated with cannabis use. More clinical research into the effects and side-effects of CaM is needed to draw the boundaries of the medical utility of cannabis.

Association between county level cannabis dispensary counts and opioid related mortality rates in the United States: panel data study

OBJECTIVE

To examine county level associations between the prevalence of medical and recreational cannabis stores (referred to as dispensaries) and opioid related mortality rates.

DESIGN

Panel regression methods.

SETTING

812 counties in the United States in the 23 states that allowed legal forms of cannabis dispensaries to operate by the end of 2017.

PARTICIPANTS

The study used US mortality data from the Centers for Disease Control and Prevention combined with US census data and data from Weedmaps.com on storefront dispensary operations. Data were analyzed at the county level by using panel regression methods.

MAIN OUTCOME MEASURE

The main outcome measures were the log transformed, age adjusted mortality rates associated with all opioid types combined, and with subcategories of prescription opioids, heroin, and synthetic opioids other than methadone. The associations of medical dispensary and recreational dispensary counts with age adjusted mortality rates were also analyzed.

RESULTS

County level dispensary count (natural logarithm) is negatively related to the log transformed, age adjusted mortality rate associated with all opioid types (β=-0.17, 95% confidence interval -0.23 to -0.11). According to this estimate, an increase from one to two storefront dispensaries in a county is associated with an estimated 17% reduction in all opioid related mortality rates. Dispensary count has a particularly strong negative association with deaths caused by synthetic opioids other than methadone (β=-0.21, 95% confidence interval -0.27 to -0.14), with an estimated 21% reduction in mortality rates associated with an increase from one to two dispensaries. Similar associations were found for medical versus recreational storefront dispensary counts on synthetic (non-methadone) opioid related mortality rates.

CONCLUSIONS

Higher medical and recreational storefront dispensary counts are associated with reduced opioid related death rates, particularly deaths associated with synthetic opioids such as fentanyl. While the associations documented cannot be assumed to be causal, they suggest a potential association between increased prevalence of medical and recreational cannabis dispensaries and reduced opioid related mortality rates. This study highlights the importance of considering the complex supply side of related drug markets and how this shapes opioid use and misuse.

The associations of medical marijuana policies with opioid-related health care utilization

OBJECTIVE

To examine the associations between medical marijuana policies and opioid-related hospitalizations and emergency department visits.

DATA SOURCES

We utilized quarterly rates of hospital discharge data from the Healthcare Cost and Utilization Project's (HCUP) Fast Stats Database from 2005 to 2016 along with state-level sociodemographic data from US Census Bureau and Bureau of Labor Statistics and opioid-related state health policy data from publicly available sources for the analysis.

STUDY DESIGN

Analyses were carried out using a difference-in-differences regression approach. We estimate heterogeneous effects of medical marijuana policies such as initial policy, presence of active dispensary, and home cultivation on opioid-related hospitalizations and emergency department visits related to opioids.

DATA COLLECTION/EXTRACTION METHODS

Publicly available secondary data were collected, linked, and analyzed. Observations with missing values for explanatory variables were excluded from the analysis.

PRINCIPAL FINDINGS

Regression results indicate that type of medical marijuana policy has varying effects on opioid-related hospitalizations and emergency department visits. States that allow home cultivation of medical marijuana experienced significant positive associations with opioid-related hospitalizations and emergency department visits, while no effect was observed with medical marijuana dispensaries. Moreover, recreational marijuana policies were positively associated with opioid-related hospitalizations.

CONCLUSIONS

The findings indicate that the effects of medical marijuana policies on opioid-related hospitalizations and emergency department visits vary depending on the type of medical marijuana policy. Our findings indicate that the implementation of home cultivation of marijuana is positively associated with hospitalizations and emergency department visits related to opioids, suggesting that easier access to marijuana among opioid users may result in adverse health conditions that need treatment.

Using the National Incident-Based Reporting System (NIBRS) to examine racial and ethnic disparities in cannabis incidents

Background: Reducing racial and ethnic arrest disparities is one driver of cannabis legalization in the US., but outcomes of cannabis policies and equity provisions remain unknown. Early research finds legalization reduces total cannabis incidents, but disparities persist. In response, novel research approaches are emerging, but a comprehensive assessment of their strengths and limitations is needed, particularly when using data sources developed for other purposes. Objectives: This perspective assesses the National Incident-Based Reporting System (NIBRS), originally developed for crime statistics, as a means to surveil cannabis incident disparities. Methods: Massachusetts NIBRS (2000-2013) illustrates discussion points, including around sample inclusion, data integrity, and missing data. Results: We find that NIBRS is a comprehensive source for state-level monitoring if used with knowledge of its limitations. However, drawing conclusions about disparities requires careful assessment of sample inclusion and any changes to participation rates, data integrity, reporting changes, and missing variables, before analysis and reporting. Conclusion: NIBRS utility would increase with greater or required jurisdiction participation, guidance for collection of racial and ethnic data, and required ethnicity reporting. Despite limitations, cannabis disparity analyses using NIBRS can provide key insights for increasing equity in states considering and enacting cannabis legalization.

Facing the option for the legalisation of cannabis use and supply in New Zealand: An overview of relevant evidence, concepts and considerations

ISSUES

Non-medical cannabis policies are changing, including towards legalisation-with-regulation frameworks. New Zealand will hold a public referendum on cannabis legalisation in 2020. We reviewed data on cannabis use and health/social harms; policy reform options; experiences with and outcomes of reforms elsewhere; and other relevant considerations towards informing policy choices in the upcoming referendum.

APPROACH

Relevant epidemiological, health, social, criminal justice and policy studies and data were identified and comprehensively reviewed.

KEY FINDINGS

Cannabis use is common (including in New Zealand) and associated with risks for health and social harms, mainly concentrated in young users; key harms are attributable to criminalisation. 'Decriminalisation' reforms have produced ambivalent results. Existing cannabis legalisation frameworks vary considerably in main parameters. Legalisation offers some distinct advantages, for example regulated use, products and user education, yet outcomes depend on essential regulation parameters, including commercialisation, and policy ecologies. While major changes in use are not observed, legalisation experiences are inconclusive to date, including mixed health and social outcomes, with select harms increasing and resilient illegal markets. It is unclear whether legalisation reduces cannabis exposure or social harms (e.g. from enforcement) for youth.

IMPLICATIONS/CONCLUSIONS

No conclusive overall evidence on the outcomes of legalisation elsewhere exists, nor is evidence easily transferable to other settings. Legalisation offers direct social justice benefits for adults, yet overall public health impacts are uncertain. Legalisation may not categorically improve health or social outcomes for youth. Legalisation remains a well-intended, while experimental policy option towards more measured and sensible cannabis control and overall greater policy coherence, requiring close monitoring and possible adjustments depending on setting-specific outcomes.

Medical marijuana and workers' compensation claiming

We study the effect of state medical marijuana laws (MMLs) on workers' compensation (WC) claiming among adults. Medical marijuana is plausibly related to WC claiming by allowing improved symptom management, and thus reduced need for the benefit, among injured or ill workers. We use data on claiming drawn from the Annual Social and Economic supplement to the Current Population Survey over the period 1989 to 2012, coupled with a differences-in-differences design to provide the first evidence on this relationship. Our estimates show that, post MML, WC claiming declines, both the propensity to claim and the level of income from WC. These findings suggest that medical marijuana can allow workers to better manage symptoms associated with workplace injuries and illnesses and, in turn, reduce need for WC. However, the reductions in WC claiming post MML are very modest in size.

Race/Ethnicity Differences in Trends of Marijuana, Cigarette, and Alcohol Use Among 8th, 10th, and 12th Graders in Washington State, 2004-2016

Accurate estimates of substance use in the teenage years by race/ethnicity may help identify when to intervene to prevent long-term substance use disparities. We examined trends in past 30-day use of marijuana, cigarette, and alcohol among 8th, 10th, and 12th graders in Washington State, which passed a recreational marijuana law in 2012 and initiated retail marijuana sales in 2014. Data are from the 2004-2016 Washington Healthy Youth Surveys (n = 161,992). We used time series regression models to assess linear and quadratic trends in substance use for the full sample and stratified on race/ethnicity and grade level and examined relative differences in prevalence of use by race/ethnicity. In Washington, across all racial/ethnic groups, marijuana use peaked in 2012. Although there was not a significant overall change in marijuana use for the full sample across the study period, there was a statistically significant increase in use among 12th graders and a statistically significant decrease among 8th graders. Relative to Whites, Asians had a lower prevalence of marijuana use, whereas all other race/ethnicity groups had a higher prevalence of use. Prevalence of marijuana use is particularly high among American Indian/Alaska Native and Black youth and has increased most rapidly among 12th grade Hispanic/Latinx youth. There were large and statistically significant decreases in alcohol and cigarette use across the study period for the full sample, as well as for each race/ethnicity group. These findings highlight the need for continued monitoring of trends in use among these groups and potentially warrant consideration of selective interventions that specifically focus on students of color and that include developmentally-appropriate strategies relevant to each grade.

Impact of Medical Marijuana Laws on State-Level Marijuana Use by Age and Gender, 2004-2013

In states that have passed medical marijuana laws (MMLs), marijuana use (MU) increased after MML enactment among people ages 26 and older, but not among ages 12-25. We examined whether the age-specific impact of MMLs on MU varied by gender. Data were obtained from the 2004-2013 restricted-use National Survey on Drug Use and Health, aggregated at the state level. The exposure was a time-varying indicator of state-level MML (0 = No Law, 1 = Before Law, 2 = After Law). Outcomes included past-month MU prevalence, daily MU prevalence among past-year users (i.e., 300+ days/year), and past-year marijuana use disorder (MUD) prevalence. Linear models tested the state-level MML effect on outcomes by age (12-17, 18-25, 26+) and gender. Models included a state-level random intercept and controlled for time- and state-level covariates. Past-month MU did not increase after enactment of MML in men or women ages 12-25. Among people 26+, past-month MU increased for men from 7.0% before to 8.7% after enactment (+ 1.7%, p < 0.001) and for women from 3.1% before to 4.3% after enactment (+ 1.1%, p = 0.013). Among users 26+, daily MU also increased after enactment in both genders (men 16.3 to 19.1%, + 2.8%, p = 0.014; women 9.2 to 12.7%, + 3.4%, p = 0.003). There were no statistically significant increases in past-year MUD prevalence for any age or gender group after MML enactment. Given the statistically significant increase in daily use among past-year users aged 26+ following enactment, education campaigns should focus on informing the public of the risks associated with regular marijuana use.

The Interplay Between Marijuana-Specific Risk Factors and Marijuana Use Over the Course of Adolescence

Permissive attitudes and norms about marijuana use and perceptions of low harm from use are considered risk factors for adolescent marijuana use. However, the relationship between risk and use may be reciprocal and vary across development and socializing domains. We examined the bidirectional relationships between marijuana-specific risk factors in individual, parent, peer, and community domains and adolescent marijuana use. Longitudinal data came from a sample of 2002 adolescents in 12 communities. Controlling for sociodemographic covariates and communities in which the individuals resided, autoregressive cross-lagged models examined predictive associations between the risk factors and marijuana use. After accounting for concurrent relationships between risk and use and stability in behavior over time, early adolescence and the transition to high school were particularly salient developmental time points. Specifically, higher risk in all four domains in grades 7 and 9 predicted greater use 1 year later. Moreover, youth's perception of lax community enforcement of laws regarding adolescent use at all time points predicted increases in marijuana use at the subsequent assessment, and perceived low harm from use was a risk factor that prospectively predicted more marijuana use at most of the time points. Finally, greater frequency of marijuana use predicted higher levels of risk factors at the next time point in most socializing domains throughout adolescence. Prevention programs should take into account developmental transitions, especially in early adolescence and during the transition to high school. They also should focus on the reciprocal relationships between use and risk across multiple socializing domains.

A Daily Study Comparing Alcohol-Related Positive and Negative Consequences for Days With Only Alcohol Use Versus Days With Simultaneous Alcohol and Marijuana Use in a Community Sample of Young Adults

BACKGROUND

Alcohol and marijuana are psychoactive substances commonly used by young adults and are independently associated with numerous acute and long-term consequences. Many young adults engage in simultaneous alcohol and marijuana (SAM) use to cross-fade (i.e., to enhance the effects of intoxication), although the extent to which alcohol use and alcohol-related consequences increase on SAM occasions compared to alcohol-only occasions is unclear. This study examines daily data among a sample of SAM users comparing SAM days to other days when young adults only used alcohol.

METHODS

A sample of 409 young adults (age 18 to 25; M_age  = 21.6, SD = 2.2; 50.9% women) who reported SAM use in the past month completed 2 bursts of 14 days of daily surveys (28 days in total) assessing alcohol use, alcohol-related consequences, and SAM use.

RESULTS

Multilevel models based on alcohol-only and SAM days (n = 3,016 days; 391 individuals) indicated young adults drank more alcohol on SAM days compared to alcohol-only days (with no marijuana use). Similarly, days with SAM use were associated with more alcohol-related positive and negative consequences. The daily association between SAM use and positive consequences was statistically significant, after accounting for the amount of alcohol consumed; in contrast, the association between SAM use and negative consequences was diminished and nonsignificant.

CONCLUSIONS

Among young adult SAM users, days with SAM use were associated with more alcohol use and positive consequences compared to days they only drank alcohol. Further examination of the motivational context for engaging in SAM use, as well as potential physiological interactions between alcohol and marijuana use on alcohol's effects, is warranted. Alcohol interventions might benefit from addressing increased alcohol use and alcohol-related consequences as risks associated with SAM use.

Changes in alcohol and cigarette consumption in response to medical and recreational cannabis legalization: Evidence from U.S. state tax receipt data

BACKGROUND

Whether medical or recreational cannabis legalization impacts alcohol or cigarette consumption is a key question as cannabis policy evolves, given the adverse health effects of these substances. Relatively little research has examined this question. The objective of this study was to examine whether medical or recreational cannabis legalization was associated with any change in state-level per capita alcohol or cigarette consumption.

METHODS

Dependent variables included per capita consumption of alcohol and cigarettes from all 50 U.S. states, estimated from state tax receipts and maintained by the Centers for Disease Control and National Institute for Alcohol Abuse and Alcoholism, respectively. Independent variables included indicators for medical and recreational legalization policies. Three different types of indicators were separately used to model medical cannabis policies. Indicators for the primary model were based on the presence of active medical cannabis dispensaries. Secondary models used indicators based on either the presence of a more liberal medical cannabis policy ("non-medicalized") or the presence of any medical cannabis policy. Difference-in-difference regression models were applied to estimate associations for each type of policy.

RESULTS

Primary models found no statistically significant associations between medical or recreational cannabis legalization policies and either alcohol or cigarette sales per capita. In a secondary model, both medical and recreational policies were associated with significantly decreased per capita cigarette sales compared to states with no medical cannabis policy. However, post hoc analyses demonstrated that these reductions were apparent at least two years prior to policy adoption, indicating that they likely result from other time-varying characteristics of legalization states, rather than cannabis policy.

CONCLUSION

We found no evidence of a causal association between medical or recreational cannabis legalization and changes in either alcohol or cigarette sales per capita.

Who's Buying What and How Much? Correlates of Purchase Behaviors From Medical Marijuana Dispensaries in Los Angeles, California

Venue-based distribution of marijuana has become the normative model in the United States to obtain marijuana. This study examines one-time purchase behaviors at medical marijuana dispensaries (MMDs) to identify potential venue- and individual-level targets for prevention. We used a two-stage, venue-based sampling approach to randomly select patrons exiting 16 MMDs in Los Angeles, California during the spring of 2013. Patrons (N = 595) reported their discrete purchase behaviors during their most recent visit to the sampled MMD. We used hierarchical linear modeling to examine the amount spent on marijuana products, regressed on characteristics of the sampled dispensaries and their patrons. We used hierarchical generalized linear modeling to examine the likelihood of purchasing specific types of marijuana products and total grams of loose-leaf buds purchased. Patrons spent US$41.73 on average, with a range of $0-$330. We observed significant variation in purchase behaviors across MMDs and associations between venues located within high median income census tracts and a higher total amount spent and lower odds of purchasing only loose-leaf buds. The networked distance between a patron's home and the sampled MMD was positively associated with the total amount spent and total quantity of buds purchased. We also found significant relationships between medical conditions reported for use in three models: total amount spent, purchase of pre-rolled joints, and total grams of buds purchased. Policy makers may want to explore regulating the availability of specialty items that may be attractive to naïve users, such as pre-rolled joints or edibles, or high-concentration products that may be sought out by regular, heavy users.

Early evidence of the impact of cannabis legalization on cannabis use, cannabis use disorder, and the use of other substances: Findings from state policy evaluations

Background: The past decade has seen unprecedented shifts in the cannabis policy environment, and the public health impacts of these changes will hinge on how they affect patterns of cannabis use and the use and harms associated with other substances.Objectives: To review existing research on how state cannabis policy impacts substance use, emphasizing studies using methods for causal inference and highlighting gaps in our understanding of policy impacts on evolving cannabis markets.Methods: Narrative review of quasi-experimental studies for how medical cannabis laws (MCLs) and recreational cannabis laws (RCLs) affect cannabis use and use disorders, as well as the use of or harms from alcohol, opioids, and tobacco.Results: Research suggests MCLs increase adult but not adolescent cannabis use, and provisions of the laws associated with less regulated supply may increase adult cannabis use disorders. These laws may reduce some opioid-related harms, while their impacts on alcohol and tobacco use remain uncertain. Research on RCLs is just emerging, but findings suggest little impact on the prevalence of adolescent cannabis use, potential increases in college student use, and unknown effects on other substance use.Conclusions: Research on how MCLs influence cannabis use has advanced our understanding of the importance of heterogeneity in policies, populations, and market dynamics, but studies of how MCLs relate to other substance use often ignore these factors. Understanding effects of cannabis laws requires greater attention to differences in short- versus long-term effects of the laws, nuances of policies and patterns of consumption, and careful consideration of appropriate control groups.

Mapping regulatory models for medicinal cannabis: a matrix of options

Objective The aim of the present study was to develop a framework for assessing regulatory options for medicinal cannabis in Australia. Methods International regulatory regimes for medicinal cannabis were reviewed with a qualitative policy analysis approach and key policy features were synthesised, leading to a conceptual framework that facilitates decision making across multiple dimensions. Results Two central organising dimensions of medicinal cannabis regulation were identified: cannabis supply and patient authorisation (including patient access). A number of the different supply options can be matched with a number of different patient authorisation options, leading to a matrix of possible regulatory regimes. Conclusions The regulatory options, as used internationally, involve different forms of cannabis (synthetic and plant-based pharmaceutical preparations or herbal cannabis) and the varying extent to which patient authorisation policies and procedures are stringently or more loosely defined. The optimal combination of supply and patient authorisation options in any jurisdiction that chooses to make medicinal cannabis accessible will depend on policy goals. What is known about the topic? Internationally, regulation of medicinal cannabis has developed idiosyncratically, depending on formulations that were made available and local context. There has been no attempt to date in the scientific literature to systematically document the variety of regulatory possibilities for medicinal cannabis. What does this paper add? This paper presents a new conceptual schema for considering options for the regulation of medicinal cannabis, across both supply and patient authorisation aspects. What are the implications for practitioners? The design of regulatory systems in Australia, whether for pharmaceutical or herbal products, is a vital issue for policy makers right now as federal and state and territory governments grapple with the complexities of medicinal cannabis regulation. The conceptual schema presented herein provides a tool for more systematic thinking about the options.

Cannabis and youth protection in Colorado's commercial adult-use market: A qualitative investigation

INTRODUCTION

Arguments both for and against the legalization of cannabis often include the issue of youth protection. At the time of writing 5-years after the implementation of the Coloradan recreational cannabis market (CRCM), no statistically significant increase in consumption had been identified. This paper aimed to provide a thick descriptive account of youth prevention objectives stipulated in the pre-implementation phase of the CRCM and compare these with the real-world experience of regulators and other stakeholders involved with market implementation.

METHODOLOGY AND METHODS

A qualitative descriptive methodology was used that involved the following methods: document analysis, deductive coding, thematic analysis, and thick description. Two data sets relevant to youth protection in the context of a legal cannabis market in Colorado were examined. Data set 1 (DS1) examined government documents (n = 13) related to the pre-implementation phase from November 2012 - December 2013. Data set 2 (DS2) consisted of semi-structured face-to-face interviews conducted with key stakeholders (n = 32) in 2016 and 2017.

RESULTS

Five themes emerged including advertising restrictions (DS1), education (DS1), appropriation of funds (DS2), impact assessment (DS2), and evolving messages in prevention education campaigns (DS2).

DISCUSSION

Multiple lessons for other jurisdictions were highlighted in the study.

Using wastewater-based analysis to monitor the effects of legalized retail sales on cannabis consumption in Washington State, USA

AIMS

To perform a wastewater-based analysis to explore the impact of newly legalized retail cannabis sales on its use and to determine if this approach could estimate the size of the legal market place, which began 1 August 2014 in the study area.

DESIGN

Laboratory study of raw wastewater samples collected and analyzed over the 3-year period from 2014 to 2016.

SETTING AND PARTICIPANTS

Samples obtained from the two wastewater treatment plants that serviced a municipality of 200 000 people in the state of Washington, USA.

MEASUREMENTS

Quantitative analysis of 24-hour composite influent samples for the metabolite of the active ingredient in cannabis, 11-nor-9-Carboxy-Δ9-tetrahydrocannabinol (THC-COOH) were performed by liquid chromatography coupled to mass spectrometry.

FINDINGS

Wastewater estimates for THC-COOH increased by 9% per quarter, suggesting a doubling in cannabis consumption from 1 December 2013 to 31 December 2016. State-sold THC increased at nearly 70% per quarter, while stores operated from 1 August 2014 to 31 December 2016. Estimating the proportion of the total cannabis market supplied by state-regulated cannabis from these data is not currently achievable.

CONCLUSION

A wastewater-based measure of cannabis consumption suggests a significant increase in consumption in Washington, USA following legalization, and that legal sales appear to have displaced a large portion of the illicit market.

Associations between state-level policy liberalism, cannabis use, and cannabis use disorder from 2004 to 2012: Looking beyond medical cannabis law status

BACKGROUND

Medical cannabis laws (MCL) have received increased attention as potential drivers of cannabis use (CU), but little work has explored how the broader policy climate, independent of MCL, may impact CU outcomes. We explored the association between state-level policy liberalism and past-year cannabis use (CU) and cannabis use disorder (CUD).

METHODS

We obtained state-level prevalence of past-year CU and CUD among past year cannabis users for ages 12-17, 18-25, and 26+ from the 2004-2006 and 2010-2012 National Surveys on Drug Use and Health. States were categorized as liberal, moderate, or conservative based on state-level policy liberalism rankings in 2005 and 2011. Linear models with random state effects examined the association between policy liberalism and past-year CU and CUD, adjusting for state-level social and economic covariates and medical cannabis laws.

RESULTS

In adjusted models, liberal states had higher average past-year CU than conservative states for ages 12-17 (+1.58 percentage points; p = 0.03) and 18-25 (+2.96 percentage points; p = 0.01) but not for 26+ (p = 0.19). CUD prevalence among past year users was significantly lower in liberal compared to conservative states for ages 12-17 (-2.87 percentage points; p = 0.045) and marginally lower for ages 26+ (-2.45 percentage points; p = 0.05).

CONCLUSION

Liberal states had higher past-year CU, but lower CUD prevalence among users, compared to conservative states. Researchers and policy makers should consider how the broader policy environment, independent of MCL, may contribute to CU outcomes.

Differences in patterns of cannabis use among youth: Prevalence, perceptions of harm and driving under the influence in the USA where non-medical cannabis markets have been established, proposed and prohibited

INTRODUCTION AND AIMS

Cannabis use is the most widely used illicit substance in the USA. Currently, over half of US jurisdictions have legalised medical cannabis and nine US jurisdictions (and Washington DC) have legalised non-medical cannabis. Comparisons across jurisdictions can help to evaluate the impact of these policies. The current study examined patterns of cannabis use among youth in three categories: (i) states that have legalised non-medical cannabis with established markets; (ii) jurisdictions that recently legalised non-medical cannabis without established markets; and (iii) all other jurisdictions where non-medical cannabis is prohibited.

DESIGN AND METHODS

Data come from an online survey conducted among 4097 US youth aged 16-19 recruited through a commercial panel in July/August 2017. Regression models were fitted to examine differences between regulatory categories for cannabis consumption, perceived access to cannabis, modes of use, perceptions of harm and cannabis-impaired driving. All estimates represent weighted data.

RESULTS

States that had legalised non-medical cannabis had higher prevalence, easier access and lower driving rates than non-legal states. There were few differences between states with established non-medical cannabis markets and those that had recently legalised.

DISCUSSION AND CONCLUSIONS

Cannabis use among youth was higher in states that have legalised non-medical cannabis, regardless of how long the policy had been implemented or whether markets had been established. This suggests that differences between states with and without legal non-medical cannabis may partly be due to longer-term patterns established prior and highlights the importance of longitudinal evidence to evaluate the impact of cannabis policies.

The effects of medical marijuana laws on cannabis-involved driving

This study uses data from the Fatality Analysis Reporting System and a differences-in-differences model to examine the effect of state medical marijuana laws (MMLs) on cannabis-involved driving among U.S. drivers involved in a fatal crash between 1993-2014. Findings indicate that MMLs in general have a null effect on cannabis-positive driving, as do state laws with specific supply provisions including home cultivation and unlicensed or quasi-legal dispensaries. Only in jurisdictions with state-licensed medical marijuana dispensaries did the odds of marijuana-involved driving increase significantly by 14 percent, translating into an additional 87 to 113 drivers testing positive for marijuana per year. Sensitivity analyses reveal these findings to be generally robust to alternate specifications, although an observed spillover effect consistent with elevated drugged driving enforcement in bordering states weakens a causal interpretation. Still, reasonable policy implications are drawn regarding drugged driving prevention/enforcement and regulations governing dispensary delivery services and business siting decisions.

Co-use of cannabis, tobacco, and alcohol during adolescence: policy and regulatory implications

Legislative reforms have legalized use of cannabis for medical and recreational purposes. Efforts to evaluate the public health impact of these changes have predominantly focused on determining whether liberalizing cannabis policies has increased cannabis use patterns. Co-use of cannabis and other licit substances, namely tobacco and alcohol, is common during the developmental period of adolescence, which is generally characterized by an increase in risk-taking and novelty-seeking. However, limited research has sought to evaluate the potential implications of reforms to medical and recreational cannabis laws on concurrent and simultaneous use of cannabis, tobacco, and alcohol during adolescence. The current report reviews the extant literature detailing the prevalence and outcomes associated with concurrent and simultaneous cannabis-tobacco and cannabis-alcohol use, including recent work that has examined how concurrent and simultaneous use may be influenced by cannabis reform. This review details how the cannabis landscape and cannabis retail marketplace have evolved and briefly summarizes the corresponding policy and regulatory challenges that have emerged. The report concludes with a focused cannabis co-use research agenda that adopts different strategies including behavioural economic, self-administration, and survey research methods.

Trends in and correlates of medical marijuana use among adults in the United States

BACKGROUND

Trends in and correlates of medical marijuana use are important to inform ongoing clinical, research, policy, and programmatic efforts. This study assessed trends in and correlates of medical marijuana use among U.S. adults.

METHODS

We analyzed data from approximately 147,200 U.S. civilians aged 18 or older who participated in the 2013-2015 National Surveys on Drug Use and Health. Descriptive analyses, multivariable logistic regressions, and zero-truncated native binomial regressions were applied.

RESULTS

Among U.S. adults, the prevalence of medical marijuana use increased from 1.2% in 2013 to 1.6% in 2015 (p = 0.0007). After adjusting for covariates, adults residing in medical marijuana states (states with legalized medical marijuana use) were 1.3 times more likely to use marijuana medically in 2015 than in 2013 (adjusted odds ratio (AOR) = 1.3, 95% confidence interval (CI) = 1.03-1.61), and adults in nonmedical marijuana states were 1.4 times more likely to report medical marijuana use in 2015 than in 2013 (AOR = 1.4, 95% CI = 1.05-1.90). Among adults who used marijuana exclusively for medical purposes in the past 12 months, trends in 12-month cannabis use disorders, daily or near daily use, and the number of days of marijuana use remained unchanged during 2013-2015. We identified how correlates of medical marijuana use among adults in medical marijuana states differed from their counterparts in nonmedical marijuana states.

CONCLUSIONS

Adults were more likely to use marijuana medically in 2015 than in 2013 in both medical and nonmedical marijuana states. Clinicians need to learn about and address evolving patterns of medical marijuana use in patients.

Marijuana and the Risk of Fatal Car Crashes: What Can We Learn from FARS and NRS Data?

Lab studies have shown that marijuana can severely impair driving skills. Epidemiological studies, however, have been inconclusive regarding the contribution of marijuana use to crash risk. In the United States, case-control studies based on the merging of comparable crash Fatality Analysis Reporting System (FARS) and non-crash National Roadside Survey (NRS) data have been applied to assess the contribution of drugs to crash risk, but these studies have yielded confusing, even contradictory results. We hypothesize that such a divergence of results emanates from limitations in the databases used in these studies, in particular that of the FARS. The goal of this effort is to examine this hypothesis, and in doing so, illuminate the pros and cons of using these databases for drugged-driving research efforts. We took advantage of two relatively recent cannabis crash risk studies that, despite using similar databases (the FARS and the NRS) and following similar overall approaches, yielded opposite results (Li, Brady, & Chen, 2013; Romano, Torres-Saavedra, Voas, & Lacey, 2014). By identifying methodological similarities and differences between these efforts, we assessed how the limitations of the FARS and NRS databases contributed to contradictory and biased results. Because of its limitations, we suggest that the FARS database should neither be used to examine trends in drug use nor to obtain precise risk estimates. However, under certain conditions (e.g., based on data from jurisdictions that routinely test for drugs, with as little variation in testing procedures as possible), the FARS database could be used to assess the contribution of drugs to fatal crash risk relative to other sources of risk such as alcohol.

Medical Marijuana and Marijuana Legalization

State-level marijuana liberalization policies have been evolving for the past five decades, and yet the overall scientific evidence of the impact of these policies is widely believed to be inconclusive. In this review we summarize some of the key limitations of the studies evaluating the effects of decriminalization and medical marijuana laws on marijuana use, highlighting their inconsistencies in terms of the heterogeneity of policies, the timing of the evaluations, and the measures of use being considered. We suggest that the heterogeneity in the responsiveness of different populations to particular laws is important for interpreting the mixed findings from the literature, and we highlight the limitations of the existing literature in providing clear insights into the probable effects of marijuana legalization.

Marijuana buyers in the United States, 2010-2014

BACKGROUND

Obtaining or purchasing marijuana in the U.S. can be done only in certain states via a lawful market for medical or non-medical (recreational) purposes, or via an unlawful market ("black market") by home cultivation and unlicensed vendors and individuals. Given the evolving U.S. state marijuana legislation landscape, the objective of this study is to describe individuals who report buying marijuana in the past year by selected characteristics and U.S. geographical location.

METHODS

Using data from the 2010-2014 National Survey on Drug Use and Health (NSDUH), we conducted bivariate chi-square tests to examine sociodemographic and selected behavioral indicators associated with buying marijuana and analyzed these factors in a multivariable logistic regression model. NSDUH participants were the noninstitutionalized civilian population aged 12+ (approximately 62,100 individuals per year) who reported using marijuana in the past year (approximately 12,400 annual average).

RESULTS

A weighted estimate of approximately 18.5 million individuals aged 12+ reported buying marijuana in the past year (59% of marijuana users). Overall, buyers of marijuana were more likely to be male, report using marijuana for a greater number of days, and to meet the criteria for substance use disorder and marijuana dependence. Data showed differences of proportion of marijuana buyers by state of residence.

CONCLUSIONS

Given recent changes in state laws and policies and the increased demand for marijuana products, continued monitoring of the U.S. marijuana market in coming years is important in order to understand consumption and buying patterns among at-risk segments of the population, especially youth.

The potential impact of cannabis legalization on the development of cannabis use disorders

Specific provisions of legal cannabis legislation and regulation could influence cannabis initiation, frequency and quantity of use, and progression to cannabis use disorder. This brief essay highlights scientifically based principles and risk factors that underlie substance use and addiction that can be leveraged to inform policies that might mitigate the development and consequences of cannabis use disorder. Specifically, pharmacologic, access/availability, and environmental factors are discussed in relation to their influence on substance use disorders to illustrate how regulatory provisions can differentially affect these factors and risk for addiction. Relevant knowledge from research and experience with alcohol and tobacco regulation are also considered. Research designed to inform regulatory policy and to evaluate the impact of cannabis legislation on cannabis use and problems is progressing. However, definitive findings will come slowly, and more concerted efforts and resources are needed to expedite this process. In the meantime, policymakers should take advantage of the large body of scientific literature on substance use to foster empirically-guided, common sense approaches to cannabis policy that focus on prevention of addiction.

How Medical Marijuana Smoothed the Transition to Marijuana Legalization in the United States

Public support for legalizing marijuana use increased from 25% in 1995 to 60% in 2016, rising in lockstep with support for same-sex marriage. Between November 2012 and November 2016, voters in eight states passed ballot initiatives to legalize marijuana sales for nonmedical purposes-covering one-fifth of the US population. These changes are unprecedented but are not independent of the changes in medical marijuana laws that have occurred over the past 20 years. This article suggests five ways in which the passage and implementation of medical marijuana laws smoothed the transition to nonmedical legalization in the United States: (a) They demonstrated the efficacy of using voter initiatives to change marijuana supply laws, (b) enabled the psychological changes needed to destabilize the "war on drugs" policy stasis, (c) generated an evidence base that could be used to downplay concerns about nonmedical legalization, (d) created a visible and active marijuana industry, and (e) revealed that the federal government would allow state and local jurisdictions to generate tax revenue from marijuana.

National Trends in Substance Use and Use Disorders Among Youth

OBJECTIVE

To examine trends in the 12-month prevalence of patterns of substance use and substance use disorders (SUDs) among US youth during 2002 through 2014.

METHOD

Data were from 288,300 persons 12 to 17 years old who participated in the 2002 to 2014 National Surveys on Drug Use and Health. Descriptive analyses and bivariable and multivariable logistic regressions were applied.

RESULTS

During 2002 through 2014, among US youth, the 12-month prevalence of any substance use decreased by 27.1% (from 43.2% to 31.5%); among youth users, the 12-month prevalence of SUDs decreased by 28.9% (from 27.0% to 19.2%), and the ratio of substance dependence to abuse decreased from 2.2 to 1.6. Multiple substance use was common and was associated with SUDs. During 2002 through 2014, the prevalence of using marijuana and alcohol only, using marijuana only, and having marijuana use disorders only increased, whereas most other trends were downward. Increases in age at first substance use were associated with downward trends in any substance use. Upward trends in age at first substance use, youth and parental strong disapproval of cigarette use, and youths' seatbelt-wearing prevalence and downward trends in substance use patterns were associated with the downward trend in SUDs among youth users.

CONCLUSION

The 12-month prevalence of any substance use among youth and SUDs among youth users decreased during 2002 through 2014. Postponing age at first use of any substance is critical among youth in the United States. Future research is needed to better understand the interrelations between specific risk and protective factors, age at first substance use, substance use patterns, and SUDs among youth users.

Implementing the teen marijuana check-up in schools-a study protocol

BACKGROUND

Substance misuse is now encountered in settings beyond addiction specialty care, with schools a point-of-contact for student access to behavioral health services. Marijuana is a leading impetus for adolescent treatment admissions despite declining risk perception, for which the Teen Marijuana Check-Up (TMCU)-a tailored adaptation of motivational enhancement therapy-offers an efficacious service option. To bridge the knowledge gap concerning effective and affordable technical assistance strategies for implementing empirically supported services, the described trial will test such a strategy to facilitate school-based TMCU implementation.

METHODS

A type II effectiveness/implementation hybrid trial will test a novel strategy for a TMCU purveyor to provide technical assistance on an 'as-needed' basis when triggered by a fidelity drift alarm bell, compared to resource-intensive 'gold-standard' technical assistance procedures of prior efficacy trials. Trial procedures adhere to the EPIS framework as follows: (1) initial mixed-method exploration of the involved school contexts and identification of TMCU interventionist candidates in elicitation interviews; (2) interventionist preparation via a formally evaluated training process involving a two-day workshop and sequence of three training cases; (3) post-training implementation for 24 months for which trained interventionists are randomized to 'as-needed' or 'gold-standard' technical assistance and self-referring students randomized (in 2:1 ratio) to TMCU or waitlist/control; and (4) examination of TMCU sustainment via interventionist completion of biannual outcome assessments, cost analyses, and exit interviews. Hypothesized effects include non-differential influence of the competing technical assistance methods on both TMCU fidelity and intervention effectiveness, with lesser school costs for the 'as-needed' than 'gold-standard' technical assistance and greater reduction in the frequency of marijuana use expected among TMCU-exposed students relative to those assigned to waitlist/control.

DISCUSSION

This trial-occurring in Washington state as legislative, fiscal, and sociocultural forces converge to heighten exposure of American adolescents to marijuana-related harms-is set to advance understanding of best implementation practices for this and other efficacious, school-based interventions through examination of a data-driven technical assistance method. If shown to be clinically useful and affordable, the concept of a fidelity drift alarm could be readily translated to other empirically supported services and in other health settings.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03111667 registered 7 April 2017.

Cannabis decriminalization and the age of onset of cannabis use

BACKGROUND

In the Czech Republic in 2010 a law was introduced decriminalizing personal possession of small quantities of several illicit drugs, including cannabis.

METHODS

We use 2012 survey data to examine the effect of a change in cannabis policy on the age of onset of cannabis use. We estimate the effect of the policy change using a mixed proportional hazards framework that models the transition to first cannabis use.

RESULTS

The change in cannabis policy did not affect the transition to first cannabis use.

CONCLUSION

We find no evidence of cannabis decriminalization affecting the age of onset of cannabis use.

Observations of the role of science in the United States medical cannabis state policies: Lessons learnt

BACKGROUND

Clinical trials have shown cannabis to be effective in the treatment of some medical conditions and there is mounting public and political pressure to enact laws enabling the use of cannabis for medicinal purposes. To date, 28 United States (U.S.) states and the District of Columbia have enacted medical cannabis laws. This study sought to identify the main issues pertaining to the development of medical cannabis laws in the U.S, including the role of scientific evidence.

METHODS

Data were collected from three groups of participants: government officials, lobbyists and medical professionals involved in the medical cannabis debate in five selected states in the U.S.; researchers from the same five states conducting funded research in the alcohol and other drugs field; and members of the International Society for the Study of Drug Policy. The data were analysed using thematic analysis.

RESULTS

Six major themes emerged in relation to the factors influencing policy: scientific evidence plays a limited role in the development of policy; the available research is limited and mixed; there is a need for clearer communication and active dissemination of evidence to policy makers; researchers need to consider what research is likely to impact on policy; scientific evidence is not a major factor in policy development; and there is a need to consider evidence within a political context.

CONCLUSION

Researchers need to be aware of the political context in which medical cannabis laws are or are not enacted and consider ways in which research findings can achieve a higher profile within this context.

Cannabis Use and Cannabis Use Disorders Among Youth in the United States, 2002-2014

OBJECTIVE

To examine trends in past-year cannabis use (CU) and cannabis use disorders (CUD) among youth in the United States, when related changes began, and factors associated with these changes.

METHODS

This study used data from 288,300 persons aged 12-17 years who participated in the 2002-2014 National Survey on Drug Use and Health. Descriptive analyses and bivariable and multivariable logistic regressions were applied (using the year 2002 as the reference group for most analyses).

RESULTS

The prevalence of past-year CU among youth decreased from 15.8% in 2002 to 13.1% in 2014 (this downward trend occurred during 2002-2007 only [β = -0.0540, P < .0001]). Among youth cannabis users, the prevalence of past-year CUD decreased from 27.0% in 2002 to 20.4% in 2014, with a downward trend starting in 2011 (β = -0.0970, P = .0001). During 2002-2014, the prevalence of past-year tobacco use and alcohol use decreased and prevalences of past-year CU increased among tobacco users and among alcohol users. Our multivariable results suggest that declines in past-year tobacco use (but not alcohol use) among youth were associated with declines in past-year CU during 2010-2014. Past-year CU and CUD were higher among racial/ethnic minorities (except for non-Hispanic Asians and Hawaiians/Pacific Islanders for CU) than non-Hispanic whites and were similar between male and female youth during 2002-2014.

CONCLUSIONS

In the United States, compared to 2002, even after adjusting for covariates, CU decreased among youth during 2005-2014, and CUD declined among youth cannabis users during 2013-2014. Associations between declines in tobacco use and decreased CU suggest the importance of tobacco use control and prevention among youth.

State and National Contexts in Evaluating Cannabis Laws: A Case Study of Washington State

As of January 2016, 23 U.S. states and the District of Columbia have legalized medical or nonmedical cannabis, with more likely to follow. This dynamic policy context represents a substantial challenge for policy evaluation. Part I of this article provides a summary of state-level cannabis policy components across states and federal action regarding state-level policies. Part II presents a detailed history of cannabis policies in Washington State from 1998 to 2015 and analyzes the potential impacts of the policy changes on cannabis supply and demand. As an early adopter of both medical and nonmedical cannabis policies, Washington State provides an excellent example of the key elements to be considered in evaluating the relationship between policy changes and cannabis use. We highlight the importance of the interplay of federal enforcement priorities and previously adopted state-level cannabis regimes in interpreting the potential impacts of new cannabis policies.

State-level medical marijuana laws, marijuana use and perceived availability of marijuana among the general U.S. population

BACKGROUND

Little is known on how perceived availability of marijuana is associated with medical marijuana laws. We examined the relationship between medical marijuana laws (MML) and the prevalence of past-month marijuana use, with perceived availability of marijuana.

METHODS

Data were from respondents included in the National Survey of Drug Use and Health restricted use data portal 2004-2013. Multilevel logistic regression of individual-level data was used to test differences between MML and non-MML states and changes in prevalence of past-month marijuana use and perceived availability from before to after passage of MML among adolescents, young adults and older adults controlling for demographics.

RESULTS

Among adults 26+, past-month prevalence of marijuana use increased from 5.87% to 7.15% after MML passage (Adjusted Odds Ratio (AOR): 1.24 [1.16-1.31]), but no change in prevalence of use was found for 12-17 or 18-25 year-olds. Perceived availability of marijuana increased after MML was enacted among those 26+ but not in younger groups. Among all age groups, prevalence of marijuana use and perception of it being easily available was higher in states that would eventually pass MML by 2013 compared to those that had not. Perceived availability was significantly associated with increased risk of past-month marijuana use in all age groups.

CONCLUSION

Evidence suggests perceived availability as a driver of change in use of marijuana due to MML. To date, this has only occurred in adults 26+ and different scenarios that could explain this change need to be further explored.

How does state marijuana policy affect US youth? Medical marijuana laws, marijuana use and perceived harmfulness: 1991-2014

AIMS

To test, among US students: (1) whether perceived harmfulness of marijuana has changed over time, (2) whether perceived harmfulness of marijuana changed post-passage of state medical marijuana laws (MML) compared with pre-passage; and (3) whether perceived harmfulness of marijuana statistically mediates and/or modifies the relation between MML and marijuana use as a function of grade level.

DESIGN

Cross-sectional nationally representative surveys of US students, conducted annually, 1991-2014, in the Monitoring the Future study.

SETTING

Surveys conducted in schools in all coterminous states; 21 states passed MML between 1996 and 2014.

PARTICIPANTS

The sample included 1 134 734 adolescents in 8th, 10th and 12th grades.

MEASUREMENTS

State passage of MML; perceived harmfulness of marijuana use (perceiving great or moderate risk to health from smoking marijuana occasionally versus slight or no risk); and marijuana use (prior 30 days). Data were analyzed using time-varying multi-level regression modeling.

FINDINGS

The perceived harmfulness of marijuana has decreased significantly since 1991 (from an estimated 84.0% in 1991 to 53.8% in 2014, P < 0.01) and, across time, perceived harmfulness was lower in states that passed MML [odds ratio (OR) = 0.86, 95% confidence interval (CI) = 0.75-0.97]. In states with MML, perceived harmfulness of marijuana increased among 8th graders after MML passage (OR = 1.21, 95% CI = 1.08-1.36), while marijuana use decreased (OR = 0.81, 95% CI = 0.72-0.92). Results were null for other grades, and for all grades combined. Increases in perceived harmfulness among 8th graders after MML passage was associated with ~33% of the decrease in use. When adolescents were stratified by perceived harmfulness, use in 8th graders decreased to a greater extent among those who perceived marijuana as harmful.

CONCLUSIONS

While perceived harmfulness of marijuana use appears to be decreasing nationally among adolescents in the United States, the passage of medical marijuana laws (MML) is associated with increases in perceived harmfulness among young adolescents and marijuana use has decreased among those who perceive marijuana to be harmful after passage of MML.

Clearing the haze: the complexities and challenges of research on state marijuana laws

As states increasingly liberalize marijuana laws, high-quality research is needed that will inform the public and policymakers about the health and societal impact of these laws. However, there are many challenges to studying marijuana policy, including the heterogeneity of the drug and its use, the variability in the laws and their implementation from state to state, the need to capture a wide variety of relevant outcomes, and the poorly understood influence of marijuana commercialization. Furthermore, current instruments generally fail to distinguish between types of users and lack accurate and detailed measures of use. This review provides a background on marijuana laws in the United States and an overview of existing policy research, discusses methodological considerations when planning analysis of state marijuana laws, and highlights specific topics needing further development and investigation.