Heterogeneity of state medical marijuana laws and adolescent recent use of alcohol and marijuana: Analysis of 45 states, 1991-2011

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.

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.

Recreational cannabis legislation and binge drinking in U.S. adolescents and adults

BACKGROUND

Recreational cannabis laws (RCLs) may have spillover effects on binge drinking. Our aims were to investigate binge drinking time trends and the association between RCLs and changes in binge drinking in the United States (U.S.).

METHODS

We used restricted National Survey on Drug Use and Health data (2008-2019). We examined trends in the prevalence of past-month binge drinking by age groups (12-20, 21-30, 31-40, 41-50, 51+). Then, we compared model-based prevalences of past-month binge drinking before and after RCL by age group, using multi-level logistic regression with state random intercepts, an RCL by age group interaction term, and controlling for state alcohol policies.

RESULTS

Binge drinking declined overall from 2008 to 2019 among people aged 12-20 (17.54% to 11.08%), and those aged 21-30 (43.66% to 40.22%). However, binge drinking increased among people aged 31+ (ages 31-40: 28.11% to 33.34%, ages 41-50: 25.48% to 28.32%, ages 51+: 13.28% to 16.75%). When investigating model-based prevalences after versus before RCL, binge drinking decreased among people aged 12-20 (prevalence difference=-4.8%; adjusted odds ratio (aOR)=0.77, [95% confidence interval (CI) 0.70-0.85]), and increased among participants aged 31-40 (+1.7%; 1.09[1.01-1.26]), 41-50 (+2.5; 1.15[1.05-1.26]) and 51+ (+1.8%; 1.17[1.06-1.30]). No RCL-related changes were noted in respondents ages 21-30.

CONCLUSIONS

Implementation of RCLs was associated with increased past-month binge drinking in adults aged 31+ and decreased past-month binge drinking in those aged < 21. As the cannabis legislative landscape continues to change in the U.S., efforts to minimize harms related to binge drinking are critical.

Relationships of Cannabis Policy Liberalization With Alcohol Use and Co-Use With Cannabis: A Narrative Review

PURPOSE

The liberalization of cannabis policies has the potential to affect the use of other substances and the harms from using them, particularly alcohol. Although a previous review of this literature found conflicting results regarding the relationship between cannabis policy and alcohol-related outcomes, cannabis policies have continued to evolve rapidly in the years since that review.

SEARCH METHODS

The authors conducted a narrative review of studies published between January 1, 2015, and December 31, 2020, that assessed the effects of cannabis policies on the use of alcohol in the United States or Canada.

SEARCH RESULTS

The initial search identified 3,446 unique monographs. Of these, 23 met all inclusion criteria and were included in the review, and five captured simultaneous or concurrent use of alcohol and cannabis.

DISCUSSION AND CONCLUSIONS

Associations between cannabis policy liberalization and alcohol use, alcohol-related outcomes, and the co-use of alcohol and cannabis were inconclusive, with studies finding positive associations, no associations, and negative associations. Although several studies found that cannabis policy liberalization was associated with decreases in alcohol use measures, these same studies showed no impact of the cannabis policy on cannabis use itself. The lack of a consistent association was robust to subject age, outcome measure (e.g., use, medical utilization, driving), and type of cannabis policy; however, this may be due to the small number of studies for each type of outcome. This paper discusses several notable limitations of the evidence base and offers suggestions for improving consistency and comparability of research going forward, including a stronger classification of cannabis policy, inclusion of measures of the alcohol policy environment, verification of the impact of cannabis policy on cannabis use, and consideration of mediation effects.

Behavioral economic interactions between cannabis and alcohol purchasing: Associations with disordered use

As cannabis policy changes, there is an urgent need to understand interactions between cannabis and alcohol couse. An online sample of 711 adult past-month cannabis and alcohol users completed both single-item hypothetical purchasing tasks for cannabis and alcohol and cross-commodity purchasing tasks assessing adjusting-price cannabis with concurrently available, fixed-price alcohol, and vice versa. Participants provided information about cannabis and alcohol use patterns, and completed the Alcohol and Cannabis Use Disorder Identification Tests (AUDIT and CUDIT, respectively). Group data showed that cannabis and alcohol served as complements (as the price of the adjusting-price commodity increased, consumption of both commodities decreased). However, individual data showed substantial variability with nontrivial proportions showing patterns of complementarity, substitution, and independence. More negative slopes (greater complementarity) for fixed-price cannabis and alcohol were both associated with greater self-reported drug consumption and CUDIT and AUDIT scores. The negative relation between cross-price slope and CUDIT/AUDIT score indicates that individuals who treat cannabis and alcohol more as complements are more likely to experience disordered use. Based on these cross-commodity purchasing data, when both cannabis and alcohol are concurrently available at low prices, both may be used at high levels, whereas limiting consumption of one commodity (e.g., through increased price) may reduce consumption of the other. These data show the importance of examining individual participant analyses of behavioral economic drug interactions and suggest that manipulation of cost (e.g., through taxes) or cosale restrictions are potential public health regulatory mechanisms for reducing alcohol and cannabis use and couse behaviors. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

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.

Medical Cannabis Laws and Adolescent Alcohol Use Initiation

Background

The effects of medical cannabis laws (MCLs) on adolescent alcohol use remains unclear. Previous literature investigates alcohol consumption rather than alcohol initiation among adolescents, and does not examine the effect by sociodemographic characteristics and state-level dispensary status. We used population representative, state-level data to examine the relationship between MCLs and adolescent alcohol initiation.

Methods

Data for this study were derived from the Youth Risk Behavior Survey (YRBS), a nationally representative, cross-sectional school-based survey administered by the Centers for Disease Control (CDC) in odd-numbered years from 1991 to 2015. We used a difference-in-difference model to assess pre and post effects of state MCL enactment on adolescent alcohol use initiation. Logistic regression analyses assessed associations between MCLs and varying ages of initiation. We further stratified our results by race/ethnicity, gender, and dispensary status.

Results

Results from adjusted logistic regression models showed higher odds of initiating alcohol among adolescents in states without MCLs when compared to adolescents in states with MCLs (OR 1.37, [95% CI = 1.29, 1.44]). This effect was consistent across age, race/ethnicity, and gender groups. Reductions in self-report of alcohol initiation were also consistently found in multiple age strata (9-10, 11-12, and 13-14), though this finding did not reach conventional levels of statistical detection in all race/ethnicities.

Conclusions

Our findings support a substitutive effect, suggesting that adolescents in states with MCLs, as opposed to states without MCLs, may substitute cannabis for alcohol. Considering the evolving landscape of medical cannabis laws and the proliferation of state-level legalization laws, further research into the effects of such policies, such as adult-use cannabis laws, is warranted to further elucidate their effects on adolescent substance use.

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.

A review investigating the relationship between cannabis use and adolescent cognitive functioning

Given varying state-level laws regarding cannabis use, the objective of the review was to summarize contemporary literature on the relationship between adolescent cognitive function and academic performance with cannabis use. Frequency and quantity of cannabis use were associated with decreased functional connectivity of the brain. Earlier age at cannabis initiation and more frequent use was associated with poorer executive control and academic performance. Social determinants such as minimal parental monitoring, peer use and low social cohesion were associated with more frequent adolescent use. Race/ethnicity and residence were other factors influencing cannabis use. To prevent cannabis use disorders among adolescents, interventions should aim to prevent early initiation that can lead to chronic use in youth who may be more at risk.

How medical are states' medical cannabis policies?: Proposing a standardized scale

BACKGROUND

There are important differences in medical cannabis laws across the U.S.. However, prior studies investigating the effect of medical cannabis laws on outcomes disregard this heterogeneity. Findings from the body of literature using a simple dichotomous assessment of whether a particular state has enacted a medical cannabis law are equivocal or conflicting. To advance the science, a national advisory group of experts in medical cannabis developed and utilized a systematic methodology, the "medicalization of cannabis laws standardized scale" (MCLaSS), to characterize and quantify state laws' degree of medicalization, the extent to which medical cannabis is treated similarly to pharmaceutical medications.

METHODS

We conducted a systematic review of state-level medical cannabis laws in the U.S. Using the novel MCLaSS, we calculated seven domain scores (patient-clinician relationship, manufacturing and testing, product labeling, types of products, supply and dose limit, prescription drug monitoring program, and dispensing practices) and a summary score for each state which had enacted medical cannabis laws as of July 2019.

RESULTS

There is substantial heterogeneity in the degree of medicalization of states' medical cannabis laws, as demonstrated by the MCLaSS summary score, which ranged from 23 (least medicalized) to 86 (most medicalized).

CONCLUSION

This methodology will advance the evidence base about the impact of medical cannabis laws on patient and public health outcomes, which is urgently needed to ensure the development of policies that minimize the risks and maximize the benefits of medical cannabis.

Medical marijuana laws (MMLs) and dispensary provisions not associated with higher odds of adolescent marijuana or heavy marijuana use: A 46 State Analysis, 1991-2015

Background: States are rapidly moving to reverse marijuana prohibition, most frequently through legalization of medical marijuana laws (MMLs), and there is concern that marijuana legalization may affect adolescent marijuana use. Methods: This natural-experimental study used state Youth Risk Behavior Survey (YRBS) data collected from participants in grades 9-12 from 1991 to 2015 in 46 states (N = 1,091,723). Taking advantage of heterogeneity across states in MML status and MML dispensary design, difference-in-difference estimates compared states with enacted MMLs/dispensaries to non-MML/dispensaries states. Multivariable logistic regression modeling was used to adjust for state and year effects, and student demographics. The main outcome assessed was past 30-day adolescent marijuana use ["any" and "heavy" (≥20)]. Results: In the overall sample, the adjusted odds of adolescents reporting any past 30-day marijuana use was lower in states that enacted MMLs at any time during the study period (OR 0.94, 95% CI 0.89 to 0.99; p < .05), and in states with operational dispensaries in 2015 (OR 0.93, 95% CI 0.88 to 0.99; p < .05). Among grade cohorts, only 9th graders showed a significant effect, with lower odds of use with MML enactment. We found no effects on heavy marijuana use. Conclusions: This study found no evidence between 1991 and 2015 of increases in adolescents reporting past 30-day marijuana use or heavy marijuana use associated with state MML enactment or operational MML dispensaries. In a constantly evolving marijuana policy landscape, continued monitoring of adolescent marijuana use is important for assessing policy effects.

Children's Knowledge of Cannabis and Other Substances in States with Different Cannabis Use Regulations

Background: Public acceptance of cannabis continues to increase across the US, yet there has been little research on how cannabis legalization affects young children. The present study compared knowledge of cannabis and other substances among children living in states with different cannabis laws and examined whether the association between such substance knowledge and externalizing behavior varies by state cannabis regulations. Methods: Participants were from the Adolescent Brain Cognitive Development^SM Study (ABCD Study®) at the baseline assessment (N = 11,875, ages 9-11, collected from 2016 to 2018). Chi-square difference tests were used to compare nested models testing group differences in knowledge of substances and the association between externalizing disorder/behavior and substance knowledge as a function of state legality of cannabis use (recreational, medical, low THC/CBD, none). Results: Children living in states with more permissive cannabis laws had a greater knowledge of cannabis and reported more alcohol experimentation. In contrast, knowledge regarding alcohol, tobacco, and other illicit drugs was not greater in children from states with more permissive cannabis laws. Externalizing disorder/behavior was not significantly associated with cannabis knowledge in any group and not significantly different across groups. The association between externalizing disorder/behavior and illicit drug knowledge was significant only in states with the recreational and medical use laws but did not differ significantly across groups. Conclusion: Children living in environments with more permissive cannabis regulations have greater knowledge of cannabis, but not other substances, and report more experimentation with alcohol.

Mode of Marijuana Use among Young Adults: Perceptions, Use Profiles, and Future Use

BACKGROUND

Given changes in marijuana regulations, retail, and products and potential impact on use, we examined young-adult perceptions of different modes of use, the proportion using via different modes (e.g. smoking, vaping, ingesting), and associations with the use levels and stability of use over time.

METHODS

We analyzed baseline and one-year follow-up survey data (Fall 2018-2019) among 3,006 young adults (ages 18-34) across six metropolitan areas (Atlanta, Boston, Minneapolis-St. Paul, Oklahoma City, San Diego, Seattle). Measures included marijuana use frequency and mode, sociodemographics, other substance use, and social influences.

RESULTS

Participants' rated the following modes of use as: least harmful/addictive: topicals, oral pills, joint/bowl; most socially acceptable: joint/bowl, edibles/beverages, vaporized; and most harmful/addictive and least acceptable: wrapped, vaped, or waterpipe/bong with tobacco. Baseline past-month use prevalence was 39.2% (n = 1,178). Most frequent use mode was smoking (joints/bowls/cigar papers; 54.0%), vaping (21.8%), via pipe/bong (15.1%), and ingesting (9.1%). Multinomial logistic regression indicated that participants in states with legalized marijuana retail were at greater odds for using via modes other than smoking; participants more frequently using were at greater odds for using via pipe/bong (vs. smoking) (ps < .001). Regarding most frequent mode across time, most consistent was pipe/bong (53.3%), followed by smoking (49.3%), vaping (44.5%), and ingesting (32.9%). Past-month abstinence at follow-up was most common among those originally ingesting (34.3% abstinent), followed by smoking (23.6%), vaping (18.8%), and pipe/bong (14.8%).

CONCLUSIONS

Ongoing surveillance is needed to understand marijuana use patterns over time across different user groups (particularly by mode) and to inform interventions promoting abstinence.

Impact of state-level cannabis legalization on poly use of alcohol and cannabis in the United States, 2004-2017

BACKGROUND

Cannabis policy has shifted toward legalization in many parts of the United States (US). While attention has been focused on whether legalization will lead to changes in cannabis use, it is conceivable that legalization will also affect use of substances that individuals frequently use with cannabis. This study assessed whether cannabis legalization impacted the prevalence of poly use of cannabis and alcohol from 2004 to 2017 and estimated the prevalence of cannabis and alcohol poly use in 2017.

METHODS

Public and restricted-use data from the US 2004-2017 National Survey on Drug Use and Health were analyzed. Data on past-month cannabis and alcohol use were assessed each year. Cannabis legalization was determined by the presence or absence of medical marijuana laws (MML) and recreational marijuana laws (RML) in each state. Difference-in-difference approach was used to estimate the association of MML and RML on cannabis and alcohol use overall and by sociodemographic subgroups (e.g., age, income, education).

RESULTS

Between 2004 and 2017, poly use of cannabis and alcohol increased while alcohol-only use decreased. MML were associated with increases in poly use only among adults over age 50 and among those with higher annual incomes and higher education, while RML were associated with increases in poly use broadly among adults across sociodemographic groups.

CONCLUSIONS

Legalization of cannabis was associated with increases in cannabis-alcohol poly use in the US. RML were associated with increases across demographics, while the impact of MML was more limited to certain sociodemographic groups.

Adolescent alcohol exposure produces sex differences in negative affect-like behavior and group I mGluR BNST plasticity

Adolescent alcohol exposure increases the risk of developing alcohol use disorders (AUDs), yet the mechanisms responsible for this vulnerability remain largely unknown. One potential target for alcohol-induced changes is the circuitry that modulates negative affect and stress, two sexually dependent drivers of alcohol relapse. The bed nucleus of the stria terminalis (BNST) is a sexually dimorphic region that critically regulates negative affective- and stress-induced relapse. Group I metabotropic glutamate receptors (mGluR) are a target of interest due to their regulation of stress, anxiety behaviors, and BNST plasticity. The current studies investigate sex-dependent sensitivity to the effects of adolescent intermittent ethanol vapor exposure (AIE) on negative affect during acute and protracted alcohol withdrawal and following stress in adulthood. This work also assessed whether BNST group I mGluR-mediated long-term depression (LTD) was disrupted at these timepoints. During acute withdrawal, AIE altered LTD induced by the group I mGluR antagonist DHPG in females, but not males. During adulthood, stress unmasked persistent changes in DHPG-induced LTD and behavior that were not present under basal conditions. Females with an AIE history demonstrated enhanced negative affective-like behavior in the novelty-induced hypophagia test following restraint stress-a phenotype that could be blocked with systemic mGluR5 allosteric antagonism via MTEP. Conversely, males with an AIE history demonstrated elevated freezing in a contextual fear conditioning paradigm. These studies demonstrate long-lasting, sex-dependent phenotypes produced by AIE and suggest pharmaceutical interventions for alcohol use and comorbid disorders may be more effective if designed with sex differences in mind.

Applying and advancing best practices in opioid use disorder and addiction treatment: Introduction to the special issue on implementation science and quality improvement scholarship

To help realize the promise of evidence-based practices to stem the opioid crisis, there is a glaring need for descriptions of how practices are effectively disseminated and implemented. Unfortunately, addiction journals do not often publish addiction implementation science and non-research descriptions of quality improvement projects. This is unfortunate as these projects are more representative of how research is translated into practice in the real-world and offer guidance and practical information to help speed implementation of evidence-based practices. To support translation of research into practice, primary, secondary, and tertiary intervention implementation science and quality improvement projects should be disseminated. We are excited to again partner with the Providers' Clinical Support System for Opioid Therapies in presenting implementation and quality improvement demonstration projects in this special issue: "Implementation and Quality Improvement: Applying and Advancing Best Practices in Opioid Use Disorder and Addiction Treatment."

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.

The Public Health Concerns of Marijuana Legalization: An Overview of Current Trends

The objective of this study was to conduct a review of the benefits and adverse effects of cannabis (or marijuana) legalization in various states across the US. The current study offers a preliminary evaluation of the problems concerning marijuana legalization in several states, with the primary goal being the assessment of the impact of laws and policies governing the legalization and use of marijuana for medical purposes. A comprehensive search on cannabis and its derivatives was performed using multiple resource databases: PubMed, MEDLINE, Embase, PsycINFO, CENTRAL (Cochrane Controlled Register of Trials), government web sources, and the Department of Public Health databases. A total of 47 reports that evaluated the effects of cannabis legalization were included in this review. All review stages were conducted independently by two reviewers. Data were extracted in standardized tables by one reviewer and adjusted by a second, which were verified by the third author. We examined the use of cannabis before and after the changes in policy and the impact of marijuana legalization on traffic safety, behavior and educational achievement in adolescents, public health, tax revenues, criminal justice expenditures, and financial outcomes. We analyzed the effects and consequences of marijuana use in states that have or have not legalized marijuana. This report also includes the responsiveness of the people in states where marijuana is legalized and its value in the healthcare system. Our study highlights the existing limitations of reviews that probe the effect of decriminalizing marijuana in some states of the country. Our analysis shows that detailed and precise evaluation of policy dynamics must be conducted, taking into account the heterogeneity in population sub-groups and policies. Accordingly, in states where marijuana is used for its medicinal value and recreational purposes, people have different views on the legalization of marijuana. The complete effect of legalizing and commercializing marijuana on consumers' mental health and their educational outcomes is expected to take a longer duration prior to its achievement; unfortunately, fewer merits are anticipated. Most of the reports evaluated in this article proved to be marred with inconsistencies. Many of the stated claims did not pass a methodical evaluation. Going forward, additional data from available sources will lead to stronger conclusions. We weighed the pros and cons of marijuana legalization. However, we are certain that consumers can make better decisions by weighing each opinion by its reliability and safety.

Changes over time in marijuana use, deviant behavior and preference for risky behavior among US adolescents from 2002 to 2014: testing the moderating effect of gender and age

BACKGROUND AND AIMS

Among adolescents, risk preference and deviant behaviors are associated with marijuana use, which exhibit substantial historical trends. We examined (1) trends, (2) effect modification by sex and age, (3) associations of marijuana use with deviant behaviors and risk preferences and (4) differences by sex, age and year.

DESIGN

Adjusted logistic and relative risk regression models, using data from the 2002-14 National Survey on Drug Use and Health, annual cross-sectional surveys of US households.

SETTING

United States.

PARTICIPANTS

A nationally representative sample of adolescents aged 12-17 years (n = 230 452).

MEASUREMENTS

We estimated associations between past-year marijuana use [self-reported using computer-assisted personal interviewing/audio computer-assisted self-interviewing (CAPI/ACASI)], deviant behavior (i.e. selling drugs; stealing; attacking someone) and risk preference (i.e. getting a kick; testing oneself).

FINDINGS

Marijuana use, deviant behaviors and risk preferences declined among adolescents from 2002 to 2014. There were no significant sex or age differences in the decline of marijuana use over time. There were sex [sold drugs: β = 0.90, 95% confidence interval (CI) = 0.75, 1.04] and age (attacked someone: β = 0.32, 95% CI = 0.22, 0.42) differences in the prevalence of deviant behaviors, and trends over time differed by sex and age for attacking someone.

CONCLUSIONS

While marijuana use, deviant behavior and risk preferences among US adolescents declined from 2002 to 2014, associations have remained stable, with marijuana use positively associated with deviant behaviors and risk preferences.

Adolescent Marijuana Use, Marijuana-Related Perceptions, and Use of Other Substances Before and After Initiation of Retail Marijuana Sales in Colorado (2013-2015)

Due to the recentness of changes to marijuana policies in a number of states, the effect on adolescent use and perceptions is not yet well understood. This study examines change in adolescent marijuana use and related perceptions in Colorado, before and after the implementation of legal commercial sale of recreational marijuana for adults starting on January 1, 2014. The data are from a repeated cross-sectional survey of a representative sample of Colorado high school students, with separately drawn samples surveyed in fall 2013 (prior to implementation) and fall 2015 (18 months after implementation). We examined change in the prevalence of adolescent marijuana use, measured by lifetime use, past 30-day use, frequent use, and use on school property. To consider the possibility of heterogeneity in the change in marijuana use, we examined change in past 30-day marijuana use by demographic characteristics (sex, grade, race/ethnicity), school characteristics (poverty, percent minority), urbanicity of the school district, and whether the city or county permitted retail marijuana stores. There was an absence of significant effects for change in lifetime or past 30-day marijuana use. Among those reporting past 30-day use, frequent use and use on school property declined. There was a significant decline in the perceived harm associated with marijuana use, but we did not find a significant effect for perceived wrongfulness, perceived ease of access, or perceived parental disapproval. We did not find significant variability in past 30-day use by demographic characteristics or by school and community factors from 2013 to 2015. We did not find a significant effect associated with the introduction of legal sales of recreational marijuana to adults in Colorado on adolescent (illegal) use, but ongoing monitoring is warranted, including consideration of heterogeneity in the effects of marijuana policies.