A quasi-experimental evaluation of marijuana policies and youth marijuana use

Association of mental health related quality of life and other factors with treatment seeking for substance use disorders: A comparison of SUDs rooted in legal, partially legal, and illegal substances

The association of subjective mental health-related quality of life (MHRQOL) and treatment use among people experiencing common substance use disorders (SUDs) is not known. Furthermore, the association of a given substance's legal status with treatment use has not been studied. This work aims determine the association of MHRQOL with SUD treatment use, and how substance legal status modulates this relationship. Our analysis used nationally-representative data from the NESARC-III database of those experiencing past-year SUDs (n = 5,808) to compare rates of treatment use and its correlates among three groups: those with illicit substance use disorders (ISUDs); those with partially legal substance use disorders, i.e., cannabis use disorder (CUD); and those with fully legal substance use disorders, i.e., alcohol use disorder (AUD). Survey-weighted multiple regression analysis was used to assess the association of MHRQOL with likelihood of treatment use among these three groups, both unadjusted and adjusted for sociodemographic, behavioral, and diagnostic factors. Adults with past-year ISUDs were significantly more likely to use treatment than those with CUD and AUD. Among those with ISUDs, MHRQOL had no significant association with likelihood of treatment use. Those with past-year CUD saw significant negative association of MHRQOL with treatment use in unadjusted analysis, but not after controlling for diagnostic and other behavioral health factors. Those with past-year AUD had significant negative association of MHRQOL with treatment use in both unadjusted and adjusted analysis. If legalization and decriminalization continue, there may be a greater need for effective public education and harm reduction services to address this changing SUD landscape.

Systematic Review and Meta-Analysis: Medical and Recreational Cannabis Legalization and Cannabis Use Among Youth in the United States

OBJECTIVE

Dramatic changes in state-level cannabis laws (CL) over the past 25 years have shifted societal beliefs throughout the United States, with unknown implications for youth. In the present study, we conducted an updated systematic review and meta-analysis examining estimated effects of medical cannabis legalization (MCL) and recreational cannabis legalization (RCL) on past-month cannabis use among US youth.

METHOD

A systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, followed by a subsequent meta-analysis investigating the associations between state-level cannabis laws (ie, MCL vs non-MCL, and RCL vs non-RCL) and past-month cannabis use prevalence among US adolescents and young adults. Supplemental analyses examined age-group effects and design-related factors.

RESULTS

Our search identified 4,604 citations, 34 and 30 of which were included in qualitative and quantitative analyses, respectively. Meta-analysis of MCL studies identified no significant association between MCL and change in past-month youth cannabis use (odds ratio [OR] = 0.981, 95% CI = 0.960, 1.003). Meta-analysis of RCL studies showed significantly increased odds of past-month cannabis use (OR = 1.134, 95% CI = 1.116-1.153). Meta-analysis of more recent studies, however, showed a significantly increased odds of past-month cannabis use among both adolescents and young adults (OR = 1.089, 95% CI = 1.015,1.169, and OR = 1.221, 95% CI = 1.188,1.255, respectively).

CONCLUSION

Cannabis legalization has complex and heterogenous effects on youth use that may differ across law types. Our meta-analytic results showed modest positive effects of RCL on past-month cannabis use (more so in young adults than in adolescents) and minimal effects of MCL on these outcomes in US youth. Given the shift toward recreational legalization, additional focus on RCL effects is warranted.

State-Level Recreational Cannabis Legalization Is Not Differentially Associated with Cannabis Risk Perception Among Children: A Multilevel Regression Analysis

Introduction: As more states pass recreational cannabis laws (RCLs) for adults, there is concern that increasing (and state-sanctioned) cannabis acceptance will result in a reduced perception of risk of harm from cannabis among children. We aimed to discover whether children in states with RCLs had decreased perception of risk from cannabis compared with children in states with illicit cannabis. Methods: We analyzed data from the multisite multistate Adolescent Brain and Cognitive Development Study to determine how the perception of cannabis harm among children (age at baseline: 9-10; N=10,395) changes over time in states with and without RCLs. Using multilevel modeling, we assessed survey responses from children longitudinally across 3 years, adjusting for state-, family-, and participant-level clustering and child-level factors, including demographics (sex, race, and socioeconomic status), religiosity, and trait impulsivity. Results: There was no significant main effect of state RCLs on perceived risk of cannabis use, and no differences in change over time by state RCLs, even after controlling for demographic factors and other risk (e.g., impulsivity) and protective (e.g., religiosity) factors. Conclusions: This analysis indicates that state-level RCLs are not associated with differential perception of cannabis risk among children, even after controlling for demographics, trait impulsivity, and religiosity. Future studies could assess how perception of risk from cannabis changes as children and adolescents continue to mature in states with and without RCLs.

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.

Health, safety, and socioeconomic impacts of cannabis liberalization laws: An evidence and gap map

Background

Globally, cannabis laws and regulations are rapidly changing. Countries are increasingly permitting access to cannabis under various decriminalization, medicalization, and legalization laws. With strong economic, public health, and social justice incentives driving these domestic cannabis policy reforms, liberalization trends are bound to continue. However, despite a large and growing body of interdisciplinary research addressing the policy-relevant health, safety, and socioeconomic consequences of cannabis liberalization, there is a lack of robust primary and systematic research that comprehensively investigates the consequences of these reforms.

Objectives

This evidence and gap map (EGM) summarizes the empirical evidence on cannabis liberalization policies. Primary objectives were to develop a conceptual framework linking cannabis liberalization policies to relevant outcomes, descriptively summarize the empirical evidence, and identify areas of evidence concentration and gaps.

Search Methods

We comprehensively searched for eligible English-language empirical studies published across 23 academic databases and 11 gray literature sources through August 2020. Additions to the pool of potentially eligible studies from supplemental sources were made through November 2020.

Selection Criteria

The conceptual framework for this EGM draws upon a legal epidemiological perspective highlighting the causal effects of law and policy on population-level outcomes. Eligible interventions include policies that create or expand access to a legal or decriminalized supply of cannabis: comprehensive medical cannabis laws (MCLs), limited medical cannabidiol laws (CBDLs), recreational cannabis laws (RCLs), industrial hemp laws (IHLs), and decriminalization of cultivations laws (DCLs). Eligible outcomes include intermediate responses (i.e., attitudes/behaviors and markets/environments) and longer-term consequences (health, safety, and socioeconomic outcomes) of these laws.

Data Collection and Analysis

Both dual screening and dual data extraction were performed with third person deconfliction. Primary studies were appraised using the Maryland Scientific Methods Scale and systematic reviews were assessed using AMSTAR 2.

Main Results

The EGM includes 447 studies, comprising 438 primary studies and nine systematic reviews. Most research derives from the United States, with little research from other countries. By far, most cannabis liberalization research focuses on the effects of MCLs and RCLs. Studies targeting other laws-including CBDLs, IHLs, and DCLs-are relatively rare. Of the 113 distinct outcomes we documented, cannabis use was the single most frequently investigated. More than half these outcomes were addressed by three or fewer studies, highlighting substantial evidence gaps in the literature. The systematic evidence base is relatively small, comprising just seven completed reviews on cannabis use (3), opioid-related harms (3), and alcohol-related outcomes (1). Moreover, we have limited confidence in the reviews, as five were appraised as minimal quality and two as low quality.

Authors’ Conclusions

More primary and systematic research is needed to better understand the effects of cannabis liberalization laws on longer-term-and arguably more salient-health, safety, and socioeconomic outcomes. Since most research concerns MCLs and RCLs, there is a critical need for research on the societal impacts of industrial hemp production, medical CBD products, and decriminalized cannabis cultivation. Future research should also prioritize understanding the heterogeneous effects of these laws given differences in specific provisions and implementation across jurisdictions.

Effects of Cannabis Legalization on Adolescent Cannabis Use Across 3 Studies

INTRODUCTION

Canada, Uruguay, and 18 states in the U.S. have legalized the use of nonmedical (recreational) cannabis for adults, yet the impact of legalization on adolescent cannabis use remains unclear. This study examined whether cannabis legalization for adults predicted changes in the probability of cannabis use among adolescents aged 13-18 years.

METHODS

Data were drawn from 3 longitudinal studies of youth (spanning 1999-2020) centered in 3 U.S. states: Oregon, New York, and Washington. During this time, Oregon (2015) and Washington (2012) passed cannabis legalization; New York did not. In each study, youth average age was 15 years (total N=940; 49%-56% female, 11%-81% Black/African American and/or Latinx). Multilevel modeling (in 2021) of repeated measures tested whether legalization predicted within- or between-person change in past-year cannabis use or use frequency over time.

RESULTS

Change in legalization status across adolescence was not significantly related to within-person change in the probability or frequency of self-reported past-year cannabis use. At the between-person level, youth who spent more of their adolescence under legalization were no more or less likely to have used cannabis at age 15 years than adolescents who spent little or no time under legalization.

CONCLUSIONS

This study addresses several limitations of repeated cross-sectional studies of the impact of cannabis legalization on adolescent cannabis use. Findings are not consistent with changes in the prevalence or frequency of adolescent cannabis use after legalization. Ongoing surveillance and analyses of subpopulations are recommended.

The kids aren't alright: The effects of medical marijuana market size on adolescents

We exploit shocks to US federal enforcement policy to assess how legal medical marijuana market size affects youth marijuana use and consequences for youth traffic-related fatalities. Using hand-collected data on state medical marijuana patient rates to develop a novel measure of market size, we find that legal market growth increases youth marijuana use. Likely mechanisms are lower prices and easier access. Youth die more frequently from alcohol-involved car accidents, suggesting complementarities for youths. The consequences of marijuana legalization for youth are not immediate, but depend on how supply-side regulations affect production and prices.

Associations Between State Laws Governing Recess Policy with Children's Physical Activity and Health

BACKGROUND

State-level laws governing recess policies vary widely across the United States. We characterize the presence of such laws and assess their associations with child-level outcomes.

METHODS

The presence of a state recess law was determined using the Classification of Laws Associated with School Students (CLASS) database. Parents of 6- to 11-year-old children reported physical activity, overall health, school absences, school-related problems, and ability to make/keep friends as part of the National Survey of Children's Health (NSCH). Logistic regression was used to compare outcomes in states with and without recess laws cross-sectionally in 2018 and between 2003 and 2011/2012 using a difference-in-differences analysis.

RESULTS

In 2018, 20 states had a law recommending or requiring recess. Cross-sectionally, the odds of being physically active every day (odds ratio, 95% confidence interval: 2.8, 1.2-6.5) and having no difficulty making or keeping friends (2.9, 1.2-7.2) were significantly higher for children residing in states with versus without a recess law. There were no significant associations in the difference-in-differences model.

CONCLUSIONS

Significant cross-sectional associations in 2018 were not confirmed by a difference-in-differences analysis of two waves of the NSCH. Short follow-up time and the apparent weakness of existing state laws warrant further assessment of state-level recess law.

Societal Costs and Outcomes of Medical and Recreational Marijuana Policies in the United States: A Systematic Review

Significant support exists in the United States for legalization of marijuana/cannabis. As of 2021, 36 states and four territories approved the legalization of medical cannabis via medical marijuana laws (MMLs), and 15 states and District of Columbia (DC) have adopted recreational marijuana laws (RMLs). We performed structured and systematic searches of articles published from 2010 through September 2021. We assess the literature pertaining to adolescent marijuana use; opioid use and opioid-related outcomes; alcohol use; tobacco use; illicit and other drug use; marijuana growing and cultivation; employment, earnings, and other workplace outcomes; academic achievement and performance; criminal activity; perceived harmfulness; traffic and road safety; and suicide and sexual activity. Overall, 113 articles satisfied our inclusion criteria. Except for opioids, studies on use of other substances (illicit drugs, tobacco, and alcohol) were inconclusive. MMLs and RMLs do not generate negative outcomes in the labor market, lead to greater criminal activity, or reduce traffic and road safety.

Longitudinal trajectories of E-cigarette use among adolescents: A 5-year, multiple cohort study of vaping with and without marijuana

E-cigarette use harms adolescent health, yet it continues to escalate rapidly among teens nationwide. This longitudinal study sought to identify and differentiate between developmental trajectories of past 30-day e-cigarette use with and without marijuana (i.e., liquid THC) across adolescence (11-19 years old). Three population-based cohorts of adolescents (n = 3907; N = 461,069) living in major metropolitan areas of Texas (Houston, Dallas-Ft. Worth, San Antonio, Austin) completed up to 9 Waves of an e-cigarette use survey, from 2014 to 2019. Growth curve models (GCMs) were used to identify average trajectories of past 30-day e-cigarette use, by cohort. Growth mixture models (GMMs) were used to investigate developmental patterns in these trajectories, by cohort. Sociodemographic differences in trajectories were also investigated. Stable trajectories of e-cigarette use with and without marijuana were identified, from 11 through 19 years of age. Trajectories varied by age of onset; frequency and escalation in use; and substance used. With one exception, all trajectories of e-cigarette use escalated with age. Moreover, age of onset and progression in use were positively related. The most problematic trajectories, corresponding to more frequent use, were observed among the younger cohorts compared to the oldest. Primary prevention is critical. Interventions to prevent the onset and progression in e-cigarette use among teens must begin early (e.g., in middle school) and be sustained throughout adolescence.

Recreational Marijuana Legalization and Adolescent Use of Marijuana, Tobacco, and Alcohol

PURPOSE

Given the rapid expansion of recreational marijuana legalization (RML) polices, it is essential to assess whether such policies are associated with shifts in the use of marijuana and other substances, particularly for adolescents, who are uniquely susceptible to negative repercussions of marijuana use. This analysis seeks to provide greater generalizability, specificity, and methodological rigor than limited prior evidence.

METHODS

Youth Risk Behavior Survey data from 47 states from 1999 to 2017 assessed marijuana, alcohol, cigarette, and e-cigarette use among adolescents (14-18+ years; N = 1,077,938). Associations between RML and adolescent past-month substance use were analyzed using quasi-experimental difference-in-differences zero-inflated negative binomial models.

RESULTS

Controlling for other state substance policies, year and state fixed effects, and adolescent demographic characteristics, models found that RML was not associated with a significant shift in the likelihood of marijuana use but predicted a small significant decline in the level of marijuana use among users (incidence rate ratio = .844, 95% confidence interval [.720-.989]) and a small increase in the likelihood of any e-cigarette use (odds ratio of zero use = .647, 95% confidence interval [.515-.812]). Patterns did not vary over adolescent age or sex, with minimal differences across racial/ethnic groups.

CONCLUSIONS

Results suggest minimal short-term effects of RML on adolescent substance use, with small declines in marijuana use and increase in the likelihood of any e-cigarette use. Given the delayed rollout of commercial marijuana sales in RML states and rapid expansion of RML policies, ongoing assessment of the consequences for adolescent substance use and related health and behavioral repercussions is essential.

State Medical Marijuana Laws and Associated Marijuana Use, Attitudes, and Perceived Social Norms among Adolescents in the U.S

Statewide medical marijuana laws (MMLs) in the U.S. may be associated with adolescent marijuana use behavior, attitudes toward marijuana use, and social norms. This study used data from the National Study on Drug Use and Health (2013-2016) to examine the associations of state MML with marijuana use, use frequency, and attitudes and perceived peer and parental social norms toward using marijuana. Propensity-score matching was used to reduce selection bias between states with and without MML (matched N = 50,000). Results showed that adolescents residing in states with MML had higher odds of using marijuana in the past month and past year (OR = 1.45 and 1.49; ps < .001), higher marijuana use frequencies in the past month (β = 0.12, p < .001), relatively more neutral attitudes toward marijuana use (β = - 0.06, p < .001), and weaker perception of peer and parental disapproval of marijuana use (β = - 0.04 and -0.02, ps < .001). Our findings suggested that for the states that have implemented MML, special efforts should be strengthened to prevent and reduce adolescent marijuana use. For the states that have not yet implemented MML, the associations between MML and adolescent marijuana use attitudes and perceived norms should be taken into account when legislating medical marijuana and designing prevention and intervention efforts.

Cannabis legalization, tobacco prevention policies, and Cannabis use in E-cigarettes among youth

BACKGROUND

E-cigarettes are the most popular tobacco product among youth. As more states adopt cannabis legalization policies, youth cannabis use in e-cigarettes is a mounting concern.

METHODS

Data were from the 2016 and 2017 National Youth Tobacco Survey, a nationally-representative repeated cross-sectional survey administered to US middle and high school students. Ever use groups were categorized into e-cigarette ever users, cannabis in e-cigarette ever users, other tobacco ever users, and never users. Weighted multinomial logistic regression compared ever use groups, while controlling for state-level cannabis legalization and tobacco prevention polices, tobacco perceptions and exposures, and sociodemographic variables. Weighted prevalence of ever and current, or past 30 day, tobacco product use was determined by ever use groups.

RESULTS

Compared to e-cigarette ever users, cannabis in e-cigarette ever users increased (Adjusted Relative Risk Ratio (ARRR) = 1.65; p < 0.01) from 2016 to 2017. Medical-only and medical and recreational cannabis laws, and no e-cigarette minimum legal sales age (MLSA) and increased e-cigarette MLSA at 19 or 21 were positively associated with cannabis in e-cigarette ever users (ARRR = 1.34-1.85; p < 0.01, each). Ever and current use of all individual tobacco products was highest among cannabis in e-cigarette ever users compared to e-cigarette and other tobacco ever users.

CONCLUSIONS

Cannabis use in e-cigarettes has increased among youth, and these trends will likely continue as e-cigarettes continue to gain popularity and cannabis legalization policies proliferate. Targeted tobacco and cannabis prevention strategies are needed for youth, especially in states that have implemented cannabis 'medical and recreational laws.

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.