The effect of medical marijuana laws on adolescent and adult use of marijuana, alcohol, and other substances

Characteristics of adults with a medical cannabis license, reasons for use, and perceptions of benefit following medical cannabis legalization in Oklahoma

Little is known about the risks and benefits associated with medical cannabis legalization. The current study was an online panel survey of adult Oklahomans recruited between September and October 2020 (N = 1898). Respondents with and without a medical cannabis license were compared on sociodemographic, substance use and health characteristics, and sub-analyses focused on the characteristics of licensed and unlicensed past 30-day cannabis users. Among all participants, 19.34% (n = 367) reported that they had a medical cannabis license, and 35.73% (n = 676) reported past 30-day cannabis use. Licensees were more likely to be younger (i.e., 18-35 years of age; p = 0.001), identify as a sexual minority (p < 0.001), and report past 30-day cannabis, cigarette, alcohol, and prescription opiate use (all p's ≤ 0.003). Licensed participants most commonly reported medically-recommended cannabis use for anxiety (42.51%), depression (33.24%), sleep problems (26.98%), chronic pain (24.25%), and arthritis (12.81%). The likelihood of medically-recommended cannabis use for anxiety, depression, and chronic pain differed by age group (all p's ≤ 0.028). Licensees were most likely to perceive that cannabis delivered "very much/extreme" relief from anxiety (78.57%), sleep problems (76.30%), nausea/vomiting (70.00%), and depression (67.05%). Compared to licensed past 30-day cannabis users (n = 308), unlicensed users (n = 368) were more likely to be non-White, to have ≤ high school education, to report an annual household income <$30,000, and to report current smoking (all p's ≤ 0.027). Findings provide initial information about the personal characteristics associated with having a medical cannabis license in Oklahoma, the reasons for medical cannabis use, and the perceived medical benefits.

Causal effects of cannabis legalization on parents, parenting, and children: A systematic review

Medical and recreational cannabis legalization lead to increased cannabis use among adults. There is concern that legalization has negative implications for minors via effects on parents. We conducted a systematic review of studies examining legalization in the United States. Web of Science, PsycInfo, and PubMed were searched through May 2021, studies examining effects of legalization on maternal cannabis and other substance use during pregnancy and postpartum, perinatal outcomes, parental cannabis and other substance use and attitudes, parenting, and child outcomes were identified, and two independent reviewers extracted information on study designs, samples, and outcomes, and assessed classification of evidence and risk of bias. Forty-one studies met inclusion criteria; only 6 (15%) used the most causally informative study design (difference in differences). It is likely legalization increases maternal cannabis use during pregnancy and postpartum, parental cannabis use, and approval of adult cannabis use. Legalization may increase some adverse perinatal outcomes, though findings were inconsistent. It is likely legalization increases unintentional pediatric cannabis exposure. There is insufficient evidence for effects of legalization on child abuse and neglect, and there have been no studies examining effects of legalization on other aspects of parenting or on child adjustment. There is a critical lack of causally informative epidemiological studies examining effects of legalization on parenting and young children. Additional causally informative research is needed. Studies of parental cannabis use in a legal context are particularly needed. Commonsense guidelines must recognize the shifting national landscape around legalization while seeking to minimize potential harm to minors.

Impact of recreational cannabis legalization on cannabis use, other substance use, and drug-related offending among justice-system-involved youth

The present study assessed whether cannabis use, other types of substance use, and drug-related offending changed among 1216 justice-system-involved youth after recreational cannabis legalization. Using generalized estimating equation population-averaged models, we compared youth in California, where recreational cannabis is legalized, and Pennsylvania, where recreational use is still prohibited. Results indicated that cannabis use, cannabis selling, and driving under the influences (DUIs) increased more among Pennsylvanian than Californian youth. We found no changes in alcohol or noncannabis drug use after legalization. Cigarette use did not change significantly among Pennsylvanian youth, but Californian youth exhibited decreased cigarette use after legalization. Although not directly tested in the present analysis, it is possible that changes in state-level recreational cannabis policies throughout the U.S. may contribute to more permissive attitudes toward cannabis, which leads to higher use and use-related outcomes. Future research should continue to consider the potential impacts of legalization on other types of risky and illegal behavior.

Exploring Social Context and Psychological Distress in Adult Canadians with Cannabis Use Disorder: To What Extent Do Social Isolation and Negative Relationships Predict Mental Health?

The objectives of this study were to explore perceived social support, negative social interactions, and psychological distress in Canadian adults who experience lifetime abuse, or dependence on cannabis (ADC), and to determine whether, and the extent to which variables of interest predict psychological distress. Data were extracted from a cross-sectional, national datafile representing a sample of 1503 individuals who met the criteria for a lifetime prevalence of ADC. Levels of perceived overall social support, and several subtypes were measured using the Social Provisions Scale (SPS), negative social interactions were assessed using the Negative Social Interaction (NSI) scale, and psychological distress was examined using the Kessler Psychological Distress Scale (K10). It was observed that Canadians with ADC had significantly lower SPS scores (overall, and by subtype) and significantly higher NSI and K10 scores compared with the overall Canadian adult sample. An exploratory stepwise regression revealed that NCI scores were the most significant, positive predictor of psychological distress, which alone accounted for 20 percent of the variance, followed by reassurance of worth, attachment, and social integration which were inversely related to psychological distress. With the recent legalization of cannabis in Canada, the results of this study suggest that abuse may strongly link with negative social consequences that might serve to exacerbate psychological distress. As such, it might be beneficial to clearly understand one's social context when considering medicinal purposes of cannabis for mental health symptom management. Further, the findings also suggest that patients with cannabis addiction will likely benefit from receiving particular forms of social support. Limitations of this study and future research are considered.

The relationship between cannabis use and legalization frameworks: A cross-sectional analysis using a nationally representative survey

State policies related to cannabis have rapidly evolved but the impact of current legislative frameworks on usage is not well characterized. This study explored cannabis use patterns under different legalization statuses in the United States. The dataset included individuals from the Behavioral Risk Factor Surveillance System survey in 2017 and 2018. Respondents were categorized into limited medical use, full medical use, or full legalization groups based on their state's cannabis policies. The primary outcome was cannabis use in the past 30 days. Among users, we characterized frequency, method, and reason for use. Logistic regression models were estimated to assess associations between legal status and these outcome measures. The study sample included 168,299 respondents. The unweighted proportion of respondents reporting cannabis use were: 4.96% in states with limited medical use, 6.50% in states with full medical use, and 12.33% in states with full legalization. Adjusted odds of use were greater for the full medical use group (1.13, 95%CI:1.02-1.25) and the full legalization group (2.53, 95%CI:2.28-2.82) compared to the limited medical use group. Users were more likely to use non-smoking methods in the full legalization group compared to the limited medical use group (1.77, 95%CI:1.41-2.22). A greater proportion of users in the full legalization group reported medical usage than in the other two groups. Policymakers should consider these findings in order to allow for use while safeguarding public health.

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.

Pain, cannabis use, and physical and mental health indicators among veterans and nonveterans: results from the National Epidemiologic Survey on Alcohol and Related Conditions-III

ABSTRACT

Chronic pain is associated with mental and physical health difficulties and is prevalent among veterans. Cannabis has been put forth as a treatment for chronic pain, and changes in laws, attitudes, and use patterns have occurred over the past 2 decades. Differences in prevalence of nonmedical cannabis use and cannabis use disorder (CUD) were examined across 2 groups: veterans or nonveterans and those reporting or not reporting recent pain. Data from the National Epidemiologic Survey on Alcohol and Related Conditions-III (2012-2013; n = 36,309) were analyzed using logistic regression. Prevalence differences (PDs) for 3 cannabis outcomes (1) past-year nonmedical cannabis use, (2) frequent (≥3 times a week) nonmedical use, and (3) DSM-5 CUD were estimated for those reporting recent moderate to severe pain (veterans or nonveterans) and veterans reporting or not reporting recent pain. Difference in differences was calculated to investigate PDs on outcomes associated with residence in a state with medical cannabis laws (MCLs). Associations between physical and mental health and cannabis variables were tested. The results indicated that the prevalence of recent pain was greater among veterans (PD = 7.25%, 95% confidence interval (CI) [4.90-9.60]). Among veterans, the prevalence of frequent cannabis use was greater among those with pain (PD = 1.92%, 98% CI [0.21-3.63]), and among veterans residing in a state with MCLs, the prevalence of CUD was greater among those reporting recent pain (PD = 3.88%, 98% CI [0.36-7.39]). Findings failed to support the hypothesis that cannabis use improves mental or physical health for veterans with pain. Providers treating veterans with pain in MCL states should monitor such patients closely for CUD.

Heterogeneous health effects of medical marijuana legalization: Evidence from young adults in the United States

Legalizing marijuana for medical purposes is a longstanding debate. However, evidence of marijuana's health effects is limited, especially for young adults. We estimate the health impacts of medical marijuana laws (MML) in the U.S. among young adults aged 18-29 years using the difference-in-differences method and data from the Behavioral Risk Factors Surveillance System. We find that having MMLs with strict regulations generate health gains, but not in states with lax regulations. Our heterogeneity analysis results indicate that individuals with lower education attainments, with lower household income and without access to health insurance coverage gain more health benefits from MML with strict regulations than from MML with lax regulations. The findings suggest greater net health gains under strict controls concerning marijuana supply and access.

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.

Understanding Lower-Risk Cannabis Consumption from the Consumers' Perspective: A Rapid Evidence Assessment

Background: In the current rapid evidence assessment, we summarize the existing research on lower-risk cannabis consumption as understood by those who consume cannabis. Methods: We identified 7111 unique articles published between 1900 and 2021 using search terms related to a) cannabis consumption, b) beliefs and behaviors, and c) positive outcomes. Results: Twelve articles met our inclusion criteria. Three themes emerged that reflect lower-risk cannabis beliefs and behaviors (informed self-regulation, protective behavioral strategies, and the normalization of cannabis consumption) and one theme reflected motivations that undermine lower-risk cannabis consumption (e.g., using cannabis to cope). Conclusions: Results suggest a need for targeted lower-risk cannabis consumption research-research focused on how those who consume cannabis do so in a positive, non-problematic manner. Such research would help to inform policy and practice and, ultimately, help promote lower-risk cannabis consumption strategies.

Associations between Local Jurisdiction Ordinances and Current Use of Cannabis Products in California Adolescents

PURPOSE

Cannabis use among adolescents may have detrimental effects and use among this age group is increasing. It is important to understand how expansion of laws permitting cannabis sales may impact adolescent use. Much of the current research has explored how state-level policy decisions may impact adolescents' use behaviors; however, there is a gap in the understanding of how differences in local jurisdictional policies may also influence underage cannabis use.Procedures: The present study cross-sectionally assesses local variation in cannabis policies to explore the potential effects of local policy on underage use behaviors. Data were collected from (N = 1,573) adolescents representing 120 different localities across California, collected as a part of Project Cal Teens. Linear regression models were used to assess associations between local jurisdiction's allowance of retail sale of cannabis for adult-use and past 30-day use of non-medical (adult use) cannabis and perceived access to cannabis products.

FINDINGS

Local policy allowing cannabis retail was associated with adolescents' significantly higher past 30-day use of cannabis (β = 0.25 95% CI = 0.08, 0.42) and perceived access (β = 0.60 95% CI = 0.27, 0.94).

CONCLUSIONS

Results highlight the impact of local cannabis policies on adolescent cannabis use and perception. Considering the effects of cannabis use on adolescent development, this is an important public health concern because 14 states have already legalized recreational retail sales and growing numbers of local jurisdictions are allowing the retail sale of recreational cannabis.

Social health needs and promotive health factors scale for college students: Scale development and initial validation

Objective The psychometric properties of a measure of social determinants of health for college students entitled, The LIFESCREEN-C was developed. Participants: A sample of 226 college students completing an online survey during the 2018-2019 academic year. Methods: Tetrachoric correlations were used to confirm a three factor model. Results: Results found model fit; convergent validity with a measure of general health; and adequate internal reliability. Conclusions: The three model fit included: general social health needs, college student social health needs, and promotive social health factors. Implications for health professionals in college settings concludes.

Association between fatal opioid overdose and state medical cannabis laws in US national survey data, 2000-2011

AIMS

Most information on the relationship between medical cannabis laws (MCL) and the risk for opioid overdose fatality has been based on studies with ecological designs. To contribute additional information, we used a novel case-control design and individual-level data from national surveys to assess whether state medical cannabis laws were associated with reduced risk of fatal opioid overdose between 2000-2011.

METHODS

Data from participants surveyed in the National Health Interview Survey (NHIS) between 1986-2011 were included. For those sampled between 1986-2009, detailed mortality follow-up data were available from the National Death Index up to 12/31/2011. Opioid overdose decedents (n = 791) were classified as cases. Between 2000-2011, all cases arising in a given year were matched to adult controls who were surveyed the same year and eligible for mortality follow-up (n = 723,920). The distribution of exposure to state MCL was contrasted between cases and controls, providing an approximation of the rate ratio of fatal opioid overdose associated with MCLs. Due to a NHIS sample redesign, we stratified analysis using timeframes before and after 2005.

RESULTS

Overall, compared to controls, cases were more likely to be male, middle-aged, non-Hispanic White, separated/divorced; less educated, and have a family income below the poverty threshold. No overall association between state MCLs and the rate of opioid overdose was observed between 2000-2005 (aOR = 1.22, 95% CI: 0.83-1.79) or between 2006-2011 (aOR = 0.87, 95% CI: 0.60-1.25). No significant difference between sampling timeframes was observed (ratio of aOR's = 0.71, 95% CI: 0.49-1.01).

CONCLUSIONS

We found no overall protective relationship between state MCLs and opioid overdose. Future research with more recent mortality data and more refined cannabis policy classifications would be useful. The importance of the study is two-fold. First, the findings provide an additional source of information countering claims of a protective effect of MCLs on opioid overdoses, suggesting that other solutions to the opioid overdose crisis are needed. Second, the study offers a potentially useful design to answer important population-level public health questions.

Underage access to alcohol and its impact on teenage drinking and crime

Does underage access to alcohol increase teenage drinking and crime? To address this question, I leverage a discontinuity in legal access to alcohol at age 16 in Germany, a country with high consumption levels and a particularly early access regulation. Using detailed survey data and administrative crime records from 2005 to 2015, I detect considerable increases in drinking participation, frequency, and intensity at the legal cutoff along the middle and lower end of the distribution. These increases coincide with discrete jumps in criminal engagement under the influence of alcohol, mostly due to violent and property crimes. My findings suggest that changes in drinking intensity induce these crimes, implying a drinking-crime elasticity of 0.4 at age 16.

Simultaneous use of marijuana and alcohol: Potential prevention targets among young adults who use alcohol

Simultaneous alcohol and marijuana use (SAM) such that their effects overlap has emerged as a behavior that is riskier than using either substance separately. It has been associated with high-risk binge drinking and driving while intoxicated during young adulthood, and it has been demonstrated to cause greater physical and mental impairment than use of alcohol or marijuana separately. To identify intervention and prevention targets specific to SAM, we examined the relationships between alcohol- and marijuana-specific beliefs and attitudes (risk factors) and self-reported SAM compared to non-simultaneous co-use (CAM) and alcohol use only in the past 30 days in a sample of young adults (n = 1,023, mean age = 23.17; SD = 0.43). Of those who reported drinking alcohol in the past 30 days, 20.7% reported SAM, 12.6% reported CAM, and 66.6% reported using only alcohol. Results from multinomial logistic regression analyses indicated that some marijuana-specific risk factors (e.g., belief that it is not at all wrong for someone their age to use marijuana) differentiated SAM or CAM from alcohol use only, but alcohol-specific risk factors generally did not. However, the perceptions that parents approved of their using marijuana or frequently drinking heavily were associated with a greater likelihood of SAM compared to CAM (OR ranged from 2.25 to 3.53). Findings point to the salience of individuals' attitudes and beliefs around marijuana use and their perception of parental approval of heavy drinking and marijuana use as potential targets for prevention programs targeting risk reduction among young adults.

Prevalence and Correlates of Cannabis Use and Cannabis Use Disorder Among U.S. Veterans: Results From the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC-III)

OBJECTIVE

The authors sought to estimate the prevalence of past-12-month and lifetime cannabis use and cannabis use disorder among U.S. veterans; to describe demographic, substance use disorder, and psychiatric disorder correlates of nonmedical cannabis use and cannabis use disorder; and to explore differences in cannabis use and cannabis use disorder prevalence among veterans in states with and without medical marijuana laws.

METHODS

Participants were 3,119 respondents in the 2012-2013 National Epidemiologic Survey on Alcohol and Related Conditions-III (NESARC-III) who identified as U.S. veterans. Weighted prevalences were calculated. Logistic regression analyses tested associations of nonmedical cannabis use and cannabis use disorder with demographic and clinical correlates and examined whether prevalence differed by state legalization status.

RESULTS

The prevalences of any past-12-month cannabis use and cannabis use disorder were 7.3% and 1.8%, respectively. Lifetime prevalences were 32.5% and 5.7%, respectively. Past-12-month and lifetime cannabis use disorder prevalence estimates among nonmedical cannabis users were 24.4% and 17.4%, respectively. Sociodemographic correlates of nonmedical cannabis use and use disorder included younger age, male gender, being unmarried, lower income, and residing in a state with medical marijuana laws. Nonmedical cannabis use and use disorder were associated with most psychiatric and substance use disorders examined.

CONCLUSIONS

Among veterans, the odds of nonmedical cannabis use and use disorder were elevated among vulnerable subgroups, including those with lower income or psychiatric disorders and among survey participants residing in states with medical marijuana laws. The study findings highlight the need for clinical attention (e.g., screening, assessment) and ongoing monitoring among veterans in the context of increasing legalization of cannabis.

Adolescent exposure to cannabis marketing following recreational cannabis legalization in Canada: A pilot study using ecological momentary assessment

Objective

The goal of this pilot study was to assess the feasibility of a 9-day, smartphone-based ecological momentary assessment (EMA) protocol for tracking the frequency of Canadian adolescents' exposures to cannabis marketing, their reactions to such exposures, and the context in which exposures occur in the real-world and in real-time.

Method

Participants were n = 18 adolescents between the ages of 14 and 18 years of age. They used an EMA application to capture and describe cannabis marketing exposures through photographs and brief questionnaires assessing marketing channel and context. Participants also rated their reactions to each exposure in real-time.

Results

Results showed that participants were generally compliant with the protocol. Participants recorded 40 total exposures to cannabis marketing, representing an average of 2.2 (SD 2.3) exposures per participant during the 9-day study. Exposures tended to occur in the afternoon (45.0%) or evening (37.5%), and while participants were at home (70%) and alone (52.5%). Most exposures occurred through promotion by public figures (27.5%) or explicitly marked internet ads (27.5%).

Conclusion

This is the first study to demonstrate the feasibility and utility of EMA to capture adolescent exposures to cannabis marketing as it occurs in participants' natural environments. Our research offers an early look at the predictable wave of cannabis advertising targeting youth and a promising approach for studying its impacts in a post-legalization context, as well as a strategy for assessing policies, such as advertising restrictions, intending to mitigate the harms of early cannabis use among youth.

Illegal drug market responses to state recreational cannabis laws

BACKGROUND AND AIMS

In the United States, 15 states and the District of Columbia have implemented recreational cannabis laws (RCLs) legalizing recreational cannabis use. We aimed to estimate the association between RCLs and street prices, potency, quality and law enforcement seizures of illegal cannabis, methamphetamine, cocaine, heroin, oxycodone, hydrocodone, morphine, amphetamine and alprazolam.

DESIGN

We pooled crowdsourced data from 2010-19 Price of Weed and 2010-19 StreetRx, and administrative data from the 2006-19 System to Retrieve Information from Drug Evidence (STRIDE) and the 2007-19 National Forensic Laboratory Information System (NFLIS). We employed a difference-in-differences design that exploited the staggered implementation of RCLs to compare changes in outcomes between RCL and non-RCL states.

SETTING AND CASES

Eleven RCL and 40 non-RCL US states.

MEASURES

The primary outcome was the natural log of prices per gram, overall and by self-reported quality. The primary policy was an indicator of RCL implementation, defined using effective dates.

FINDINGS

The street price of cannabis decreased by 9.2% [β = -0.092; 95% confidence interval (CI) = -0.15-, -0.03] in RCL states after RCL implementation, with largest declines among low-quality purchases (β = -0.195; 95% CI = -0.282, -0.108). Price declines were accompanied by a 93% (β = -0.93; 95% CI = -1.51, -0.36) reduction in law enforcement seizures of cannabis in RCL states. Among illegal opioids, including heroin, oxycodone and hydrocodone, street prices increased and law enforcement seizures decreased in RCL states.

CONCLUSIONS

Recreational cannabis laws in US states appear to be associated with illegal drug market responses in those states, including reductions in the street price of cannabis. Changes in the street prices of illegal opioids analyzed may suggest that in states with recreational cannabis laws the markets for other illegal drugs are not independent of legal cannabis market regulation.

Marijuana liberalization policies and perinatal health

We studied the effect of marijuana liberalization policies on perinatal health with a multiperiod difference-in-differences estimator that exploited variation in effective dates of medical marijuana laws (MML) and recreational marijuana laws (RML). We found that the proportion of maternal hospitalizations with marijuana use disorder increased by 23% (0.3 percentage points) in the first three years after RML implementation, with larger effects in states authorizing commercial sales of marijuana. This growth was accompanied by a 7% (0.4 percentage points) decline in tobacco use disorder hospitalizations, yielding a net zero effect over all substance use disorder hospitalizations. RMLs were not associated with statistically significant changes in newborn health. MMLs had no statistically significant effect on maternal substance use disorder hospitalizations nor on newborn health and fairly small effects could be ruled out. In absolute numbers, our findings implied modest or no adverse effects of marijuana liberalization policies on the array of perinatal outcomes considered.

Use of highly-potent cannabis concentrate products: More common in U.S. states with recreational or medical cannabis laws

BACKGROUND

Highly-potent cannabis products, e.g., concentrates, entail greater risks of cannabis-related harms than lower-potency products such as plant or flower material. However, little information is available on whether individuals in U.S. states with recreational cannabis laws (RCL) or medical cannabis laws (MCL) are more likely than individuals in U.S. states without cannabis legalization (no-CL) to use highly-potent forms of cannabis.

METHODS

Cannabis-using adults in a 2017 online survey (N = 4064) provided information on state of residence and past-month cannabis use, including types of products used, categorized as low-potency (smoked or vaped plant cannabis) or high-potency (vaping or dabbing concentrates). Multivariable logistic regression models generated adjusted odds ratios (aOR) and 95% confidence intervals (CI) for use of high-potency cannabis products by state cannabis legalization status (RCL, MCL, no-CL).

RESULTS

Compared to participants in no-CL states, participants in RCL states had greater odds of using high-potency concentrate products (aOR=2.61;CI=1.77-3.86), as did participants in MCL-only states (aOR=1.55;CI=1.21-1.97). When participants in RCL states and MCL states were directly compared, those in RCL states had greater odds of using high-potency concentrate products (aOR=1.69;CI=1.27-2.42).

DISCUSSION

Although the sample was not nationally representative and the cross-sectional data precluded determining the direction of effect, results suggest that use of high-potency cannabis concentrates is more likely among those in RCL states. Clinicians in RCL states should screen cannabis users for harmful patterns of use. Policymakers in states that do not yet have RCL should consider these findings when drafting new cannabis laws, including the specific products permitted and how best to regulate them.

Cannabis vaping among adults in the United States: Prevalence, trends, and association with high-risk behaviors and adverse respiratory conditions

The e-cigarette or vaping product-use-associated lung injury outbreak in the United States has raised concerns about the potential health effects of cannabis vaping, a method of cannabis use that is becoming increasingly popular. We used 2017-2019 Behavioral Risk Factor Surveillance System data to estimate yearly prevalence and trends of past-30-day cannabis use and vaping among US adults. We used multivariable logistic regression to evaluate the associations of cannabis vaping with high-risk behaviors, asthma, and other respiratory symptoms. Our sample size was 160,209 (53,945-2017; 55,475-2018; and 50,789-2019). Past-30-day cannabis use prevalence increased from 10.0% (95% CI, 9.4%-10.7%) in 2017 to 13.4% (12.8%-12.0%) in 2019. Similarly, past-30-day cannabis vaping prevalence increased from 1.0% (0.8%-1.2%) to 2.0% (1.7%-2.2%) over the same period, with the greatest increase, 1.2% to 3.9%, observed among young adults (18-24 years). Individuals who vaped cannabis were more likely to concurrently vape nicotine. Cannabis vaping was associated with increased odds of heavy alcohol use (aOR, 1.95; 95% CI, 1.45-2.63), binge drinking (aOR, 2.82; 95% CI, 2.25-3.54), and other high-risk behaviors (aOR, 2.47; 95% CI, 1.89-3.24). In analyses adjusting for sociodemographic characteristics and body mass index, cannabis vaping was not associated with asthma (aOR, 1.03; 95% CI, 0.64-1.64) or other respiratory symptoms (aOR, 1.08; 95% CI, 0.44-2.63). Adjusting for nicotine vaping did not substantively alter these associations. The prevalence of past-30-day cannabis vaping has increased, particularly among young adults, and was associated with high-risk behaviors. Although there was no association between cannabis vaping and asthma or other respiratory symptoms, the increasing trends of cannabis vaping, particularly among young adults, raise concern and underscore the need for continued surveillance.

Cannabis Use and Misuse in Older Adults

Cannabis is the most frequently used illegal psychoactive substance by older adults. With population aging, legalization and medicalization of cannabis, and changes in perceptions of older adults toward its use, recreational and medical cannabis use/misuse is on the rise in seniors. Although there are solid data related to the adverse events of cannabis in older adults, efficacy data are lacking. Older adults are at increased risk of developing cannabis use disorder alongside other medical and psychiatric comorbidities. We review the benefits and risks associated with cannabis use, and screening and management strategies for cannabis use disorder in older adults.

GEOGRAPHICAL ACCESS TO RECREATIONAL MARIJUANA

We investigate whether adult marijuana use in Washington responds to increased local access as measured by drive time to the nearest legal marijuana retailer as well as measures of retail density. Using survey data from the Behavioral Risk Factor Surveillance System, we find that as retailers open closer to where they live, more individuals use marijuana and more frequently. These effects are concentrated among young adults (ages 18-26), women, and rural residents. Controlling for distance to the nearest retailer, we find that whether retail density affects marijuana use depends on how it is measured.

Canadian Society of Transplantation White Paper: Ethical and Legal Considerations for Alcohol and Cannabis Use in Solid Organ Listing and Allocation

Alcohol and cannabis use as a contraindication to organ transplantation is a controversial issue. Until recently, patients in Canada with alcohol-associated liver disease were required to demonstrate abstinence for 6 mo to receive a liver transplant. There is no equivalent rule that is applied consistently for cannabis use. There is some evidence that alcohol and cannabis use disorder pretransplant could be associated with worse outcomes posttransplantation. However, early liver transplantation for patients with alcohol-associated liver disease in France and in the United States has led to challenges of the 6-mo abstinence rule in Canada in the media. It has also resulted in several legal challenges arguing that the rule violates human rights laws regarding discrimination in the provision of medical services and that the rule is also unconstitutional (this challenge is still before the court). Recent legalization of cannabis use for adults in Canada has led to questions about the appropriateness of limiting transplant access based on cannabis use. The ethics committee of the Canadian Society of Transplantation was asked to provide an ethical analysis of cannabis and alcohol abstinence policies. Our conclusions were as follows: neither cannabis use nor the 6-mo abstinence rule for alcohol use should be an absolute contraindication to transplantation, and transplant could be offered to selected patients, further research should be conducted to ensure evidence-based policies; and the transplant community has a duty not to perpetuate stigma associated with alcohol and cannabis use disorders.

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.

Marijuana legalization and household spending on food and alcohol

Utilizing the Consumer Expenditure Interview Survey from 2005 to 2019, I study spending on food and alcohol following recreational marijuana law (RML). Exploiting differences in the timing of the passage of RMLs and employing two-way fixed-effects methods, I find that households located in states adopting these laws increase their quarterly spending on food, which is driven mainly by spending on food consumed away from home. Legalization of recreational marijuana also leads to increased quarterly spending on alcohol. These findings suggest a complementarity between food, alcohol, and marijuana.

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.

Optimal design of sin taxes in the presence of nontaxable sin goods

Sin good consumption entails health damage, which is in general not fully perceived by individuals, what results in its overconsumption. One way to tackle this problem is to tax these unhealthy goods. However, not all the individual choices that affect health status can be easily observed and effectively taxed by the government. This paper considers a setting where individuals can consume two types of sin goods that differ in their observability (taxability) by the government. As a benchmark, the first-best taxes for the observable and non-observable sin good are derived, considering homogeneous individuals. In the second-best setting, where observability on sin good consumption is limited, the rule for the taxable sin good is shown to depend on the degree of complementarity or substitutability with the unobservable sin good. Finally, redistributional considerations are incorporated by extending the analysis to a setting where individuals differ in their wealth and in their degree of misperception of the health damage caused by sin good consumption. Policy implications are illustrated considering physical inactivity and illicit drugs as examples of non-taxable sin goods, while alcohol, tobacco, fat and sugar account for the taxable sin goods.

Availability of medical cannabis dispensaries and cannabis abuse/dependence-related hospitalizations in California

AIMS

To estimate associations between both current- and prior-year medical cannabis dispensary densities and hospitalizations for cannabis use disorder in California, USA between 2013 and 2016.

DESIGN

Spatial analysis of ZIP code-level hospitalization discharge data using Bayesian Poisson hierarchical space-time models over 4 years.

SETTING AND CASES

California, USA from 2013 to 2016 (6832 space-time ZIP code units).

MEASUREMENTS

We assessed associations of annual hospitalizations for cannabis use disorder [assignment of a primary or secondary code for cannabis abuse and/or dependence using ICD-9-CM or ICD-10-CM (outcome)] with the total number of medical cannabis dispensaries per square mile in a ZIP code as well as dispensary temporal and spatial lags (primary exposures). Other exposure covariates included alcohol outlet densities, manual labor and retail sales densities and ZIP code-level economic and demographic conditions.

FINDINGS

One additional dispensary per square mile was associated with a median risk ratio of 1.021 (95% credible interval 1.001, 1.041). Prior-year dispensary density did not appear to be associated with hospitalizations (median risk ratio = 1.006, 95% CrI = 0.986, 1.026). Higher median household income, higher unemployment, greater off-premises alcohol outlet density and lower on-premises alcohol outlet density and poverty were all associated with decreased ZIP code-level risk of cannabis abuse/dependence hospitalizations.

CONCLUSIONS

In California, USA, the increasing density of medical cannabis dispensaries appears to be positively associated with same-year but not next-year hospitalizations for cannabis use disorder.

Differences in Opinions About Marijuana Use and Prevalence of Use by State Legalization Status

OBJECTIVE

Beliefs about marijuana use and prevalence of use may be associated with the legalization status of the state of residence. We examined differences in views and rates of use of marijuana among residents in recreationally legal, medically legal, and nonlegal states.

METHODS

We surveyed a nationally representative online panel of US adults (N = 16,280) and stratified results by marijuana legalization status of states. We compared views of residents of recreational states on benefits and risks of marijuana use to residents in other states.

RESULTS

The response rate was 56.3% (n = 9003). Residents in recreationally legal states were more likely to believe marijuana could be beneficial for pain management (73% in recreationally legal states, 67% in medically legal states, 63% in nonlegal states; P value: <0.0001), provide relief from stress, anxiety or depression (52% in recreationally legal states, 47% in medically legal states, 46% in nonlegal states; P value: 0.01), and improve appetite (39% in recreationally legal states, 36% in medically legal states, 33% in nonlegal states; P value: <0.009). In addition, residents in recreational states were significantly more likely to believe that smoking 1 marijuana joint a day is somewhat or much safer than smoking 1 cigarette a day (40.8% in recreationally legal states, 39.1% in medically legal states, and 36.1% in nonlegal states; P value: <0.0001). Residents of recreationally and medically legal states were more likely to believe second-hand marijuana smoke was somewhat or much safer than second-hand tobacco smoke (38.3% in recreationally legal states, 38.3% in medically legal states, and 35.7% in nonlegal states; P value: 0.003). Past-year marijuana use in any form (20% in recreational, 14.1% in medical, 12% in nonlegal) and past-year marijuana use of multiple forms (11.1% in recreational, 6.1% in medical, 4.9% in nonlegal) were highest among residents of recreationally legal states. Overall, prevalence of past-year use of any form of marijuana use was more common among residents of recreationally legal states compared with other states (20.3%, confidence interval [CI] 19.5, 21.1 in recreationally legal states; 15.4%, CI 14.7, 16.2 in medically legal states; 11.9%, CI 11.2, 12.6 in nonlegal states).

CONCLUSIONS

Residents in recreationally legal states were most likely to believe marijuana has benefits, marijuana smoke is safer than tobacco smoke, and have the highest rate of marijuana use. This is cause for concern, given the tide of commercialization, growing number of high-potency cannabis products, and favorable media coverage promoting use for health problems.

Trends in youth cannabis use across cannabis legalization: Data from the COMPASS prospective cohort study

Canada legalized recreational cannabis use for adults on October 17, 2018 with decision-makers emphasising the need to reduce cannabis use among youth. We sought to characterise trends of youth cannabis use before and after cannabis legalization by relying on a quasi-experimental design evaluating cannabis use among high school students in Alberta, British Columbia, Ontario, and Québec who participated in the COMPASS prospective cohort study. Overall trends in use were examined using a large repeat cross-sectional sample (n = 102,685) at two time points before legalization (16/17 and 17/18 school years) and one after (18/19 school year). Further differential changes in use among students affected by legalization were examined using three sequential four-year longitudinal cohorts (n = 5,400) of students as they progressed through high school. Youth cannabis use remains common with ever-use increasing from 30.5% in 2016/17 to 32.4% in 2018/19. In the repeat cross-sectional sample, the odds of ever use in the year following legalization were 1.05 times those of the preceding year (p = 0.0090). In the longitudinal sample, no significant differences in trends of cannabis use over time were found between cohorts for any of the three use frequency metrics. Therefore, it appears that cannabis legalization has not yet been followed by pronounced changes on youth cannabis use. High prevalence of youth cannabis use in this sample remains a concern. These data suggest that the Cannabis Act has not yet led to the reduction in youth cannabis use envisioned in its public health approach.

Associations between adolescent cannabis use and young-adult functioning in three longitudinal twin studies

Observational studies have linked cannabis use to an array of negative outcomes, including psychiatric symptoms, cognitive impairment, and educational and occupational underachievement. These associations are particularly strong when cannabis use occurs in adolescence. Nevertheless, causality remains unclear. The purpose of the present study was thus to examine associations between prospectively assessed adolescent cannabis use and young-adult outcomes (psychiatric, cognitive, and socioeconomic) in three longitudinal studies of twins (n = 3,762). Twins reporting greater cumulative cannabis use in adolescence reported higher levels of psychopathology as well as poorer socioeconomic outcomes in young adulthood. However, cannabis use remained associated only with socioeconomic outcomes (i.e., educational attainment, occupational status, and income) in monozygotic-cotwin control analyses, which account fully for shared genetic and environmental confounding. Follow-up analyses examining associations between twin differences in adolescent cannabis use and longitudinal change in academic functioning during the middle- and high-school years provided a possible mechanism for these associations, indicating that greater cannabis use during this period was associated with decreases in grade point average and academic motivation as well as increases in academic problem behavior and school disciplinary problems. Our findings thus suggest that cannabis use in adolescence has potentially causal, deleterious effects on adolescent academic functioning and young-adult socioeconomic outcomes despite little evidence suggesting a strong, causal influence on adult mental health or cognitive ability.

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.

Trends over time in adult cannabis use: A review of recent findings

In the United States, policies regarding the medical and nonmedical use of cannabis are changing rapidly. In 2021, a total of 34 US states have legalized cannabis for adult medical use, and 15 of these states have legalized adult non-medical use. These changing policies have raised questions about increasing prevalences of cannabis use, changing perceptions regarding frequent use, and potentially related outcomes such as comorbid psychiatric illness or driving under the influence of cannabis. Research regarding the correlates of any and frequent cannabis use is also developing quickly. This article reviews recent empirical studies concerning (1) adult trends in cannabis use, (2) state cannabis laws and related outcomes, and (3) emerging evidence regarding how the global coronavirus 19 pandemic may impact cannabis use patterns. We summarize recent findings and conclude with suggestions to address unanticipated effects of rapidly changing cannabis laws and policies.

Willingness to Use Cannabis for Gynecological Conditions: A National Survey

Objective: Expanded legal access to cannabis in the United States has led to its increased use for treating medical conditions. We assessed the use of and attitudes toward cannabis for treating gynecological conditions. Materials and Methods: We utilized Amazon.com Inc.'s Mechanic Turk platform to administer a survey to U.S. women 18 years and older about cannabis use for recreational and medicinal purposes and willingness to use cannabis to treat 17 gynecological conditions. We collected sociodemographic data and views about the legal status of cannabis. We used logistic regression to identify factors associated with willingness to use cannabis for gynecological conditions. Results: In our analytical sample (N = 995), women who reported ever using cannabis were more willing to use cannabis to treat a gynecological condition compared with never users (91.6% vs. 64.6%, p < 0.01). Women willing to use cannabis for gynecological conditions were most interested in using cannabis for treating gynecological pain (61.2% of never users vs. 90.0% of ever users; p < 0.001) compared with procedural pain (38.2% vs. 79.0%, respectively; p < 0.001) or other conditions (38.0% vs. 79.8%, respectively; p < 0.001). In multivariate analysis, willingness to use cannabis for a gynecological condition was associated only with a history of ever using cannabis and views that cannabis should be legal in some capacity and not by age, race, or education. Conclusions: The majority of women would consider using cannabis to treat gynecological conditions. Overall, respondents who had a history of cannabis use were more likely to report willingness to use cannabis for all gynecological conditions, but a large proportion of those who reported never using cannabis were also willing to use it.

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.

Feature Extraction for Heroin-Use Classification Using Imbalanced Random Forest Methods

The National Survey on Drug Use and Health (NSDUH) contains a large number of responses and many features. This study aims to identify features from within NSDUH that are important in classifying heroin use. Proper implementation of random forest (RF) techniques copes with the highly imbalanced nature of heroin usage among respondents to identify features that are prominent in classification models involving nonlinear combinations of predictive variables. To date, methods for the proper application of RF to imbalanced medical datasets have not been defined. Methods: Three different RF classification techniques are applied to the 2016 NSDUH. The techniques are compared using scoring criteria, including area under the precision recall curve (AUPRC), to identify the best model. Variable importance scores (VIS) are checked for stability across the three models and the VIS from the best model are used to highlight features and categories of features that most influence the classification of heroin users. Findings: The best performing method was RF with random oversampling (AUPRC = 0.5437). The category of features regarding other drug use was most important (average z-scored VIS = 1.66) followed by age-of-first-use features (0.32). The most important individual feature was cocaine usage (z-scored VIS = 11.05), followed by crack usage (6.51). The most important individual feature other than specific drug use flags was the use of marijuana under the age of 18 (3.11). This study demonstrates a method for the use of RF in feature extraction from imbalanced medical datasets with many predictors.

Cannabis Use, Cannabis Use Disorder, and Comorbid Psychiatric Illness: A Narrative Review

BACKGROUND

The landscape of attitudes, legal status and patterns of use of cannabis is rapidly changing in the United States and elsewhere. Therefore, the primary aim of this narrative review is to provide a concise overview of the literature on the comorbidity of cannabis use and cannabis use disorder (CUD) with other substance use and psychiatric disorders, and to use this information to accurately guide future directions for the field.

METHODS

A literature review of PubMed was conducted for studies relating to cannabis use, CUD, and a co-occurring psychiatric disorder. To provide an overview of representative data, the literature review focused on national-level, population-based work from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) and National Survey on Drug Use and Health (NSDUH) surveys. Considering rapidly changing cannabis laws, recent (past five-year) studies were addressed.

RESULTS

A strong body of literature shows associations between cannabis use and CUD with other drug use, psychosis, mood disorders, anxiety disorders, and personality disorders. The strongest evidence of a potential causal relationship exists between cannabis use and psychotic disorders. While some evidence shows potential directionality between cannabis use and mood and anxiety disorders, results are inconsistent. Studies have established higher rates of CUD among those with personality disorders, but little about the specifics of this relationship is understood.

CONCLUSIONS

Although the general population in the United States increasingly perceives cannabis to be a harmless substance, empirical evidence shows that cannabis use is associated both with CUD and comorbid psychiatric illness. However, there is mixed evidence regarding the role of cannabis in the etiology, course, and prognosis of a co-occurring disorder across all categories of psychiatric disorders. Future research should expand on the existing body of literature with representative, longitudinal data, in order to better understand the acute and long-term effects of cannabis on comorbid psychiatric illness.

Do-It-Yourself medicine? The impact of light cannabis liberalization on prescription drugs

Governments worldwide are increasingly concerned about the booming use of CBD (cannabidiol) products. However, we know little about the impact of their liberalization. We study a unique case of unintended liberalization of a CBD-based product (light cannabis) that occurred in Italy in 2017. Using unique and high-frequency data on prescription drug sales and by exploiting the staggered local availability of the new product in each Italian province, we document a significant substitution effect between light cannabis and anxiolytics, sedatives, opioids, anti-depressants and anti-psychotics. Results are informative for regulators and suggest that bans on light cannabis use would disregard the needs of patients to seek effective reliefs of their symptoms.

Implications of Medical and Recreational Marijuana Laws for Neuroscience Research: a Review

Purpose of Review

Review of US medical and recreational marijuana laws (MML and RML), their effects on cannabis potency, prevalence of non-medical cannabis use and cannabis use disorder (CUD) in adolescents and adults, and implications for neuroscience research, given what is known about the relationship of cannabis to neurocognitive impairments and underlying brain functioning.

Recent Findings

Cannabis potency may be increasing faster in states with MML or RML than in other states. MML and RML have not impacted prevalence in adolescents but have consistently been shown to increase rates of adult non-medical use and CUD.

Summary

Recent neurocognitive or neuroimaging studies may be more impacted by cannabis than studies conducted when MML and RML were less common. Neurocognitive or neuroimaging studies conducted in MML or RML states should carefully test potential participants for recent cannabis use. More research is needed on cannabis and cognition in medical marijuana patients.

A preliminary risk prediction model for cannabis use disorder

•

Substance use disorders are currently a major public health crisis in the US.

•

The prevalence of cannabis use disorder is rising due to legalization of cannabis.

•

This study built models to predict the risk of cannabis use disorder for a user.

•

Risk factors include personality traits, impulsivity and initial smoking enjoyment.

The ongoing trend toward legalization of cannabis for medicinal/recreational purposes is expected to increase the prevalence of cannabis use disorder (CUD). Thus, it is imperative to be able to predict the quantitative risk of developing CUD for a cannabis user based on their personal risk factors. Yet no such model currently exists. In this study, we perform preliminary analysis toward building such a model. The data come from n = 94 regular cannabis users recruited from Albuquerque, New Mexico during 2007–2010. As the data are cross-sectional, we only consider risk factors that remain relatively stable over time. We apply statistical and machine learning classification techniques that allow n to be small relative to the number of predictors. We use predictive accuracy estimated using leave-one-out-cross-validation to evaluate model performance. The final model is a LASSO logistic regression model consisting of the following seven risk factors: age; level of enjoyment from initial cigarette smoking; total score on Impulsive Sensation-Seeking Scale questionnaire; score on cognitive instability factor of Barratt Impulsivity Scale questionnaire; and scores on neuroticism, openness, and conscientiousness personality traits of Neuroticism, Extraversion, and Openness inventory. This model has an overall accuracy of 0.66 and the area under its receiver operating characteristic curve is 0.65. In summary, a preliminary relative risk model for predicting the quantitative risk of CUD is developed. It can be employed to identify users at high risk of CUD who may be provided with early intervention.

Social Learning and Addiction

Social learning theory, as originally proposed by Albert Bandura, followed 2000 years of intellectual inquiry into the determinants of human behavior. Reciprocal determinism is a central component of this theory and proposes that human behavior is determined by functional relationships between (1) personal factors, (2) the external environment, and (3) the behavior itself. Using this model, drug addiction can be viewed as resulting from the functional relationships between an individual's personal characteristics, social environment, and drug-centric behaviors. In other words, addiction can be viewed as a chronically evolving biopsychosocial disorder, encompassing dimensions that are both internal and external to the individual. Effective treatment interventions should thus target all nodes of the model and the functional relationships between them, and they must constantly evolve with the progression of the disorder. An argument is thus constructed that emphasizes the need for an organized structure of metacontingencies, operating within an individual's social environment, that targets the functional relationships between the factors that drive drug use. Optimally, these metacontingencies would operate within socially connected individuals who have the power to control the functional relationships that influence drug use, the vested interest to monitor individual and collective outcomes, the skills to determine what moment-to-moment decisions are needed to influence behavioral change, and the relative permanence necessary to carry through with the implementation of new strategies to produce outcomes that are cumulatively significant.

State medical marijuana laws, cannabis use and cannabis use disorder among adults with elevated psychological distress

BACKGROUND

Cannabis use and cannabis use disorder are more prevalent in U.S. states with medical marijuana laws (MMLs), as well as among individuals with elevated psychological distress. We investigated whether adults with moderate and serious psychological distress experienced greater levels of cannabis use and/or disorder in states with MMLs compared to states without MMLs.

METHODS

National Survey of Drug Use and Health data (2013-2017) were used to compare past-month cannabis use, daily cannabis use, and cannabis use disorder prevalence among adults with moderate and serious psychological distress in states with versus without MMLs. We executed pooled multivariable logistic regression analyses to test main effects of distress, MMLs and their interaction, after adjustment.

RESULTS

Compared to states without MMLs, states with MMLs had higher adjusted prevalence of past-month use (11.1 % vs. 6.8 %), daily use (4.0 % vs. 2.2 %), and disorder (1.7 % vs. 1.2 %). Adults with moderate and serious psychological distress had greater adjusted odds of any use (AORs of 1.72 and 2.22, respectively) and of disorder (AORs of 2.17 and 2.94, respectively), compared to those with no/mild distress. We did not find evidence of an interaction between MMLs and distress category for any outcome.

CONCLUSIONS

Associations between elevated distress and cannabis use patterns are no greater in states with MML. However, cannabis use is more prevalent in MML states. Thus, higher base rates of cannabis use and disorder among adults with elevated distress are proportionally magnified in these states.

Medical marijuana laws and driving under the influence of marijuana and alcohol

AIMS

Medical marijuana law (MML) enactment in the United States has been associated with increased cannabis use but lower traffic fatality rates. We assessed the possible association of MML and individual-level driving under the influence of cannabis (DUIC) and also under the influence of alcohol (DUIA).

DESIGN AND SETTING

Three cross-sectional U.S. adult surveys: The National Longitudinal Alcohol Epidemiologic Survey (NLAES; 1991-1992), the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC; 2001-2002), and the NESARC-III (2012-2013).

PARTICIPANTS

The total n was 118 497: 41 764, 41 184, and 35 549 from NLAES, NESARC, and NESARC-III, respectively.

MEASUREMENTS

Across the three surveys, similar questions in the Alcohol Use Disorder and Associated Disabilities Interview Schedule assessed DUIC and DUIA. Ever-MML states enacted MML between 1991-1992 and 2012-2013 (overall period). Early-MML states enacted MML between 1991-1992 and 2001-2002 (early period). Late-MML states enacted MML between 2001-2002 and 2012-2013 (late period). MML effects on change in DUIC and DUIA prevalence were estimated using a difference-in-differences specification to compare changes in MML and other states.

FINDINGS

From 1991-1992 to 2012-2013, DUIC prevalence nearly doubled (from 1.02% to 1.92%), increasing more in states that enacted MML than other states (difference-in-differences [DiD] = 0.59%; 95% CI = 0.06%-1.12%). Most change in DUIC prevalence occurred between 2001-2002 and 2012-2013. DUIC prevalence increased more in states that enacted MML 2001-2002 to 2012-2013 than in never-MML states (DiD = 0.77%; 95% CI = -0.05%-1.59%), and in two early-MML states, California (DiD = 0.82; 95% CI = 0.06-1.59) and Colorado (DiD = 1.32; 95% CI = 0.11-2.53). In contrast, DUIA prevalence appeared unrelated to MML enactment.

CONCLUSIONS

Medical marijuana law enactment in US states appears to have been associated with increased prevalence of driving under the influence of cannabis, but not alcohol.

Trajectories of cannabis use and risk for opioid misuse in a young adult urban cohort

BACKGROUND

Although much of the attention surrounding the opioid epidemic has focused on rural and suburban Whites and prescription opioids, heroin overdoses among urban Blacks are on the rise. While some argue that legalization of cannabis will combat the epidemic, there are concerns it ignores the shift in the epidemic and could increase vulnerability to opioid misuse. The goal of this study is to examine the association between cannabis use from adolescence to young adulthood with opioid misuse in a primarily urban Black cohort.

METHODS

Data are from a study of 580 youth (87 % Black and 71 % low SES) residing in Baltimore City followed from ages 6-26. Cannabis trajectories were identified between ages 14-26 using group-based trajectory modeling. Logistic regressions were conducted to examine the impact of trajectories on opioid misuse in young adulthood adjusting for individual, neighborhood and peer factors. Opioid misuse was defined as using heroin or narcotics or painkillers without a prescription between ages 19-26.

RESULTS

Four cannabis trajectories were identified: Low/Non-Users (59.7 %), Adolescent Onset Limited (19.5 %), Young Adult Onset (10.8 %), and Adolescent Onset Chronic (10.0 %). Adolescent Onset Chronic cannabis users had the highest rate of opioid misuse (44.8 %) followed by Adolescent Onset Limited (18.8 %), Young Adult Onset (14.8 %) and Low/Non-Users (8.3 %). Prevalences were significantly higher for Adolescent Onset groups relative to Low/Non-Users even after adjustment for individual, neighborhood and peer factors.

CONCLUSIONS

Adolescent onset cannabis use is associated with opioid misuse in young adulthood among urban Blacks even after adjustment for socioecological factors associated with opioid misuse.

Use of Cannabidiol for the Treatment of Anxiety: A Short Synthesis of Pre-Clinical and Clinical Evidence

Anxiety disorders have the highest lifetime prevalence of any mental illness worldwide, leading to high societal costs and economic burden. Current pharmacotherapies for anxiety disorders are associated with adverse effects and low efficacy. Cannabidiol (CBD) is a constituent of the Cannabis plant, which has potential therapeutic properties for various indications. After the recent legalization of cannabis, CBD has drawn increased attention as a potential treatment, as the majority of existing data suggest it is safe, well tolerated, has few adverse effects, and demonstrates no potential for abuse or dependence in humans. Pre-clinical research using animal models of innate fear and anxiety-like behaviors have found anxiolytic, antistress, anticompulsive, and panicolytic-like effects of CBD. Preliminary evidence from human trials using both healthy volunteers and individuals with social anxiety disorder, suggests that CBD may have anxiolytic effects. Although these findings are promising, future research is warranted to determine the efficacy of CBD in other anxiety disorders, establish appropriate doses, and determine its long-term efficacy. The majority of pre-clinical and clinical research has been conducted using males only. Among individuals with anxiety disorders, the prevalence rates, symptomology, and treatment response differ between males and females. Thus, future research should focus on this area due to the lack of research in females and the knowledge gap on sex and gender differences in the effectiveness of CBD as a potential treatment for anxiety.

A lottery test of the effect of dispensaries on emergency room visits in Arizona

In August 2012, the Arizona Department of Health Services conducted a lottery to allocate licenses for the state's first medical marijuana dispensaries. The lottery randomly selected an applicant within each of 69 contested Community Health Analysis Areas to open a dispensary. By comparing 36 zip codes with winning applications to 48 zip codes with losing applications and weighting using propensity scores based on the true probability of winning, we estimate the causal effect of the allocation of a dispensary on the emergency room visits of residents of that zip code. Outcomes of interest are emergency room visits for acute symptoms caused by cannabis, opioids, alcohol, and cocaine. Using emergency room discharge data from 2010 to 2016, we find evidence of an increase in visits for acute cannabis-related causes for the winning set of zip codes and weak evidence of an increase in visits for opioid-related causes. The results indicate that in the four years following the lottery, emergency room visits for acute cannabis causes rose by approximately 45% in allocated zip codes relative to non-allocated zip codes. Because of the high likelihood of spillovers to neighboring zip codes, these effects are likely underestimates.

The role of school characteristics in pre-legalization cannabis use change among Canadian youth: implications for policy and harm reduction

Reducing youth cannabis use in Canada is a public health priority with schools of interest as a potential modifier of behavior and as a venue for prevention programming. This work aimed to provide a basis for future policy and programming by evaluating pre-legalization cannabis use change patterns in schools and the impact of school characteristics on these patterns. Average rates of cannabis use behavior change (initiation, escalation, reduction, cessation) were collected from 88 high schools located in Ontario and Alberta, Canada participating in the COMPASS prospective cohort study. There was little variability in cannabis use behaviors between schools with intra-class correlation coefficients lowest for cessation (0.02) and escalation (0.02) followed by initiation (0.03) and reduction (0.05). Modest differences were found based on school province, urbanicity and student-peer use. Cannabis ease of access rates had no significant effect. Fewer than half the schools reported offering school drug use prevention programs; these were not significantly associated with student cannabis use behaviors. In conclusion, current school-based cannabis prevention efforts do not appear sufficiently effective. Comprehensive implementation of universal prevention programs may reduce cannabis harms. Some factors (urbanicity, peer use rates) may indicate which schools to prioritize.