Assessing the public health impacts of legalizing recreational cannabis use in the USA

Does cannabis elevate cancer risk? : Evidence from Mendelian randomization

BACKGROUND

Cannabis use is increasing annually but the relationship between cannabis use and cancer incidence is not uniform because of confounding factors. We aimed to assess the effect of cannabis use on cancer risk using a two-sample Mendelian randomization (MR) approach.

METHODS

Secondary data analyses were performed on pooled data based on Genome-Wide Association Study (GWAS), selecting data from the ICC and UK-Biobank and 23andMeInc lifetime cannabis use and cannabis use disorder related to the substance use disorders working group from the Psychiatric Genomics Consortium, then selecting highly correlated SNPs as instrumental variables. The substance use disorders working group, iPSYCH, and deCODE GWAS data, and then highly correlated SNPs were selected as instrumental variables for two-sample Mendelian randomization analyses using inverse variance weighting, MR-Egger regression, and weighted median, respectively, to evaluate the relationship between lifetime cannabis use and nine tumors, and subsequently analyzed these results in the same way using cannabis use disorders.

RESULTS

The risk of all cancers except breast cancer was not associated with lifetime cannabis use. Our inverse variance weighting method found that lifetime marijuana use reduced the breast cancer risk (P = 0.016, odds ratio [OR] = 0.981), and we subsequently conducted analyses of cannabis use disorders and cancer risk, which showed that cannabis use disorders elevated the risk of breast cancer (P = 0.007, OR = 1.007) as well as the risk of lung cancer (P = 0.014, OR = 1.122).

CONCLUSION

Large MR analyses suggest that lifetime cannabis use may reduce breast cancer risk, but cannabis use disorder exacerbates the risk of breast and lung cancer. The mechanisms responsible for this outcome remain to be investigated.

Warning Labels as a Public Health Intervention: Effects and Challenges for Tobacco, Cannabis, and Opioid Medications

Warning labels help consumers understand product risks, enabling informed decisions. Since the 1966 introduction of cigarette warning labels in the United States, research has determined the most effective message content (health effects information) and format (brand-free packaging with pictures). However, new challenges have emerged. This article reviews the current state of tobacco warning labels in the United States, where legal battles have stalled pictorial cigarette warnings and new products such as electronic cigarettes and synthetic nicotine products pose unknown health risks. This article describes the emerging research on cannabis warnings; as more places legalize recreational cannabis, they are adopting lessons from tobacco warnings. However, its uncertain legal status and widespread underestimation of harms impede strict warning standards. The article also reviews opioid medication warning labels, suggesting that lessons from tobacco could help in the development of effective and culturally appropriate FDA-compliant opioid warning labels that promote safe medication use and increased co-dispensing of naloxone.

Nicotine and Alcohol Use as Predictors of Recreational Cannabis Use in Adolescence: A Systematic Review and Narrative Synthesis

Background: The prevalence of recreational cannabis use among adolescents is a growing public health concern due to its link to short- and long-term adverse effects on adolescents' wellbeing, physical health, mental health, and interpersonal behaviors. Method: Five databases were searched from inception to March 17, 2023, for exposure (nicotine product, alcohol) and outcome (recreational cannabis) in adolescents (persons aged 10-19 years). The studies were screened independently by two reviewers, and the quality of the studies was assessed with Newcastle Ottawa and AXIS tool. PRISMA guidelines were employed in this review. Result: Twenty-one (21) studies involving 2,778,406 adolescents were included in the appraisal and heterogeneity was found among these studies. Ascertainment bias was commonly detected in thirteen (13) of the included studies. Among the substances examined as potential exposures, nicotine-product use emerged as a significant factor associated with future cannabis use among adolescents, particularly in mid-adolescence and in places where recreational cannabis use has been legalized. Conclusion: Current evidence suggests an association between nicotine-product use and subsequent recreational cannabis use among adolescents. However, further research is needed to establish causality between exposure to nicotine substances and the use of recreational cannabis within this age demographic. Additionally, there is a need for the development of prevention programs and targeted policies that continuously inform and update this vulnerable sub-population about the risks associated with cannabis use for leisure.

Is legal recreational cannabis associated with cannabis use during pregnancy, beliefs about safety, and perceived community stigma?

BACKGROUND

Among pregnant and recently pregnant people we investigated whether legal recreational cannabis is associated with pregnancy-related cannabis use, safety beliefs, and perceived community stigma.

METHODS

In 2022, we surveyed 3571 currently and recently pregnant English- or Spanish-speaking adults in 37 states. Primary outcomes included cannabis use during pregnancy and two continuous scale measures of beliefs about safety and perceived community stigma. Using generalized linear models and mixed effects ordinal logistic regression with random effects for state, we assessed associations between legal recreational cannabis and outcomes of interest, controlling for state-level and individual-level covariates and specifying appropriate functional form.

RESULTS

Those who reported cannabis use during pregnancy were more likely to believe it is safe and to perceive community stigma compared to those who did not report use during pregnancy. Legal recreational cannabis was not associated with cannabis use during pregnancy, continuation or increase in use, frequency of use, or safety beliefs. Legal recreational cannabis was associated with lower perceived community stigma (coefficient: -0.07, 95% CI: -0.13, -0.01), including among those who reported use during (coefficient = -0.22, 95% CI: -0.40, -0.04) and prior to but not during (coefficient = -0.19, 95% CI: -0.37, -0.01) pregnancy.

CONCLUSION

Findings do not support concerns that legal recreational cannabis is associated with cannabis use during pregnancy or beliefs about safety. Legal recreational cannabis may be associated with lower community stigma around cannabis use during pregnancy, which could have implications for pregnant people's disclosure of use and care-seeking behavior.

Association Between Cannabis Use and Opioid Consumption, Pain, and Respiratory Complications After Surgery: A Retrospective Cohort Analysis

BACKGROUND

Cannabis is a widely used illicit drug with effects on different pain pathways. However, interactions between cannabis and postoperative pain are unclear. Cannabis smoking also affects the lungs, but the impact of cannabis use on postoperative pulmonary complications is unknown. We hypothesized that preoperative cannabis use in adults having elective surgery is associated with higher postoperative opioid consumption. Secondarily, we tested the hypothesis that cannabis use is associated with higher pain scores, hypoxemia (oxygen saturation [Spo2]/fraction of inspired oxygen [Fio2] ratio), and higher postoperative pulmonary complications compared to nonuse of cannabis.

METHODS

In this retrospective study, we included adult patients who had elective surgeries at Cleveland Clinic Main Campus between January 2010 and December 2020. The exposure was use of cannabis within 30 days before surgery, and the control group never used cannabis. Patients who had regional anesthesia or chronic pain diagnosis were excluded. The primary outcome was postoperative opioid consumption; 3 secondary outcomes were time-weighted average (TWA) postoperative pain score, TWA Spo2/Fio2 ratio, and composite of pulmonary complications after surgery. We assessed the association between cannabis use and opioid consumption during the first 24 postoperative hours using linear regression on log-transformed opioid consumption with a propensity score-based method (inverse probability of treatment weighting [IPTW]) adjusting for confounders. We further adjusted for imbalanced confounding variables after IPTW was applied.

RESULTS

In total, 1683 of 34,521 patients were identified as cannabis users. Cannabis use was associated with increased opioid consumption, with an adjusted ratio of geometric means (95% confidence interval [CI]) of 1.30 (1.22-1.38; P < .0001) for cannabis users versus nonusers. Secondarily, (1) cannabis use was associated with increased TWA pain score, with a difference in means of 0.57 (95% CI, 0.46-0.67; P < .0001); (2) cannabis use was not associated with TWA Spo2/Fio2, with an adjusted difference in means of 0.5 (95% CI, -3.1 to 4.2; P = .76); and (3) cannabis use was not associated with a collapsed composite of pulmonary complications, with estimated odds ratio of 0.90 (95% CI, 0.71-1.13; P = .34).

CONCLUSIONS

Adult cannabis users undergoing surgeries were found to have significantly higher postoperative opioid consumption and pain scores than nonusers. Cannabis use did not have a clinically meaningful association with hypoxia or composite pulmonary complications.

Cannabis use following bariatric surgery is associated with anxiety and maladaptive eating

BACKGROUND

There are limited data regarding the association of cannabis use with outcomes after bariatric surgery. As such, it is challenging to know how to counsel patients using cannabis.

OBJECTIVES

The purpose of this study was to examine whether postsurgical cannabis use was associated with psychiatric symptoms and maladaptive eating among individuals up to 4 years after bariatric surgery.

SETTING

Single health system.

METHODS

All patients who underwent bariatric surgery over a 4-year period were invited to participate. Participants (N = 765) completed questionnaires online regarding postsurgical cannabis use, psychiatric symptoms, and maladaptive eating.

RESULTS

Any cannabis use after bariatric surgery was associated with increased likelihood of having elevated symptoms of anxiety (odds ratio [OR] = 1.88, P = .003; 37.8% versus 24.4%), increased likelihood of grazing behaviors (OR = 1.77, P = .01; 71.2% versus 58.2%), and higher scores for eating in response to depression (P = .01; 12.13 versus 10.75). Weekly cannabis use was associated with loss of control eating (OR = 1.81, P = .04; 37.2% versus 24.7%), binge eating (OR = 2.16, P = .03; 20.0% versus 10.4%), and night eating behaviors (OR = 2.11, P = .01; 40.0% versus 24.0%). Cannabis use was not associated with depression (P > .05).

CONCLUSIONS

Cannabis use after bariatric surgery was associated with anxiety symptoms and engaging in maladaptive eating behaviors. Frequent cannabis use (i.e., ≥1 per week) was associated with additional types of maladaptive eating. Clinicians involved in presurgical and postsurgical care may want to counsel patients currently using cannabis, especially those who are engaging in frequent use.

Induced negative affect's impact on self-reported cannabis use, expectancies, and problems

Substance use disorders and affective disturbances often covary. Even momentary experiences of negative affect (NA) appear linked with substance use. While strong evidence of these relations exists, NA might bias endorsements of substance use due to hindered recall and reporting processes. This hypothesis warrants further research, as accurate assessment of substance-related variables is crucial in both research and treatment settings. The present study examined the influence of NA on reporting of cannabis variables using an affect-induction paradigm. Over 700 individuals recruited from Amazon's MTurk participated. After reporting demographics and baseline affect, participants were randomly assigned to either a NA induction or control condition. Follow-up measures assessed post-induction affect and cannabis-related variables. Results revealed that the NA induction task significantly increased NA and decreased positive affect relative to the control condition. Participants assigned to the NA induction reported greater negative cannabis expectancies and more cannabis problems, even after controlling for age and educational attainment. Cannabis use and cannabis problems appeared positively related. Future research should continue to assess for the influence of NA in reporting of cannabis variables. Should subsequent work find differences in reporting of substance use that appear to covary with negative affect, clinicians and researchers alike should be mindful of the implications of potentially biased reporting on assessment, intervention, and research outcomes.

Adolescent Cannabis Use During a Period of Rapid Policy Change: Evidence From the PATH Study

PURPOSE

To determine whether shifts in various state-level cannabis policies are associated with individual-level changes in adolescent cannabis use following implementation.

METHODS

We use the restricted-access youth cohort of the PATH Study, a recent, longitudinal, and nationally representative dataset, to assess whether changes in cannabis policy affect youth cannabis use. Data include respondents aged 12 to 17 years across up to six repeated observations (N = 26,673). Hybrid (between-person and within-person) panel models are used to examine adolescent past-month cannabis use.

RESULTS

Within-person effects showed that the odds of past-month cannabis use are lower (odds ratio [OR] = 0.632; p < .05) in years when a respondent's state allowed only cannabidiol (CBD) compared to years when the state had legalized medical cannabis. The odds of past-month cannabis use are lower during years when a respondent's state had decriminalized (OR = 0.617; p < .01) or criminalized (OR = 0.648; p < .05) adult recreational cannabis possession compared to years when it was legalized. These effects were robust to numerous controls, including time and state fixed effects. By contrast, significant between-person effects became nonsignificant with state fixed effects included, implying that state-level average use distinguishes average differences between states rather than policy.

DISCUSSION

Liberalized cannabis policy is significantly associated with recent adolescent cannabis use. The most consequential policy shift associated with adolescent use is from either criminalization or decriminalization of cannabis possession to legalization, such that states making these changes should consider additional prevention efforts.

Co-Use, Simultaneous Use, and Mixing of Cannabis and Tobacco: A Cross-National Comparison of Canada and the US by Cannabis Administration Type

INTRODUCTION

Increasing cannabis legalization raises concerns that the use of tobacco, frequently used with cannabis, will also increase. This study investigated the association between the legal status of cannabis in places of residence and the prevalence of cannabis and tobacco co-use, simultaneous use, and mixing by comparing the prevalence among adults in Canada (prior to cannabis legalization) vs. adults in US states that had legalized recreational cannabis vs. US states that had not as of September 2018.

METHODS

Data were drawn from the 2018 International Cannabis Policy Study, conducted with respondents aged 16-65 in Canada and the US recruited from nonprobability consumer panels. Differences in the prevalence of co-use, simultaneous use, and mixing between tobacco and different cannabis products were examined using logistic regression models by legal status of place of residence among past-12-month cannabis consumers (N = 6744).

RESULTS

Co-use and simultaneous use in the past 12 months were most common among respondents in US legal states. Among cannabis consumers, co-use and simultaneous use were less common in US legal states, while mixing was less frequent in US states with both legal and illegal cannabis compared to Canada. Use of edibles was associated with lower odds of all three outcomes, while smoking dried herb or hash was associated with higher odds.

CONCLUSIONS

The proportion of cannabis consumers who used tobacco was lower in legal jurisdictions despite higher prevalence of cannabis use. Edible use was inversely associated with co-use, suggesting that edible use does not appear to be associated with increased tobacco use.

Cannabis use prevalence among Baby Boomers before and after implementation of recreational retail sales in California

Background

As of 2021, 21 US states and territories allowed recreational cannabis use. Although previous research has identified an overall increase in prevalence of cannabis use after legalization, it has been less clear how this change will affect different parts of the population, including older adults, and specifically Baby Boomers, born 1946–1964, given their historically higher rates of use and a higher prevalence of comorbid conditions that could be either exacerbated or addressed by cannabis use. In this study we assessed whether implementation of recreational retail sales in California was associated with increased prevalence of cannabis use among Baby Boomers.

Methods

We conducted a retrospective study of cannabis use prevalence one year before and after the implementation of recreational retail sales in California using the California Health Interview Survey (CHIS), a statewide public health surveillance dataset.

Results

We found that cannabis use prevalence did not change among Baby Boomers but increased among non-Baby Boomers. Most of the factors found to be predictive of cannabis use in past research did not predict cannabis use among Baby Boomers.

Conclusions

Baby Boomers did not change their consumption of cannabis in the first year after opening the retail market, despite previous research suggesting that cannabis consumption increases with access, and most previously identified predictors of use did not identify people who use cannabis in this generation. Further research is needed to determine whether these effects persist over time.

Affinity Assays for Cannabinoids Detection: Are They Amenable to On-Site Screening?

Roadside testing of illicit drugs such as tetrahydrocannabinol (THC) requires simple, rapid, and cost-effective methods. The need for non-invasive detection tools has led to the development of selective and sensitive platforms, able to detect phyto- and synthetic cannabinoids by means of their main metabolites in breath, saliva, and urine samples. One may estimate the time passed from drug exposure and the frequency of use by corroborating the detection results with pharmacokinetic data. In this review, we report on the current detection methods of cannabinoids in biofluids. Fluorescent, electrochemical, colorimetric, and magnetoresistive biosensors will be briefly overviewed, putting emphasis on the affinity formats amenable to on-site screening, with possible applications in roadside testing and anti-doping control.

Estimating the effects of legalizing recreational cannabis on newly incident cannabis use

Liberalized state-level recreational cannabis policies in the United States (US) fostered important policy evaluations with a focus on epidemiological parameters such as proportions [e.g., active cannabis use prevalence; cannabis use disorder (CUD) prevalence]. This cannabis policy evaluation project adds novel evidence on a neglected parameter–namely, estimated occurrence of newly incident cannabis use for underage (<21 years) versus older adults. The project’s study populations were specified to yield nationally representative estimates for all 51 major US jurisdictions, with probability sample totals of 819,543 non-institutionalized US civilian residents between 2008 and 2019. Standardized items to measure cannabis onsets are from audio computer-assisted self-interviews. Policy effect estimates are from event study difference-in-difference (DiD) models that allow for causal inference when policy implementation is staggered. The evidence indicates no policy-associated changes in the occurrence of newly incident cannabis onsets for underage persons, but an increased occurrence of newly onset cannabis use among older adults (i.e., >21 years). We offer a tentative conclusion of public health importance: Legalized cannabis retail sales might be followed by the increased occurrence of cannabis onsets for older adults, but not for underage persons who cannot buy cannabis products in a retail outlet. Cannabis policy research does not yet qualify as a mature science. We argue that modeling newly incident cannabis use might be more informative than the modeling of prevalences when evaluating policy effects and provide evidence of the advantages of the event study model over regression methods that seek to adjust for confounding factors.

The Impact of Isolated Baseline Cannabis Use on Outcomes Following Thoracolumbar Spinal Fusion: A Propensity Score-Matched Analysis

BACKGROUND

There is limited literature evaluating the impact of isolated cannabis use on outcomes for patients following spinal surgery. This study sought to compare 90-day complication, 90-day readmission, as well as 2-year revision rates between baseline cannabis users and non-users following thoracolumbar spinal fusion (TLF) for adult spinal deformity (ASD).

METHODS

The New York Statewide Planning and Research Cooperative System (SPARCS) database was queried between January 2009 and September 2013 to identify all patients who underwent TLF for ASD. Inclusion criteria were age ≥18 years and either minimum 90-day (for complications and readmissions) or 2-year (for revisions) follow-up surveillance. Cohorts were created and propensity score-matched based on presence or absence of isolated baseline cannabis use. Baseline demographics, hospital-related parameters, 90-day complications and readmissions, and two-year revisions were retrieved. Multivariate binary stepwise logistic regression identified independent outcome predictors.

RESULTS

704 patients were identified (n=352 each), with comparable age, sex, race, primary insurance, Charlson/Deyo scores, surgical approach, and levels fused between cohorts (all, p>0.05). Cannabis users (versus non-users) incurred lower 90-day overall and medical complication rates (2.4% vs. 4.8%, p=0.013; 2.0% vs. 4.1%, p=0.018). Cohorts had otherwise comparable complication, revision, and readmission rates (p>0.05). Baseline cannabis use was associated with a lower risk of 90-day medical complications (OR=0.47, p=0.005). Isolated baseline cannabis use was not associated with 90-day surgical complications and readmissions, or two-year revisions.

CONCLUSION

Isolated baseline cannabis use, in the absence of any other diagnosed substance abuse disorders, was not associated with increased odds of 90-day surgical complications or readmissions or two-year revisions, though its use was associated with reduced odds of 90-day medical complications when compared to non-users undergoing TLF for ASD. Further investigations are warranted to identify the physiologic mechanisms underlying these findings. Level of Evidence: III.

The effects of prenatal nicotine and THC E-cigarette exposure on motor development in rats

RATIONALE

In the USA, nicotine and cannabis are the most common licit and illicit drugs used among pregnant women. Importantly, nicotine and cannabis are now being combined for consumption via e-cigarettes, an increasingly popular delivery device. Both nicotine and tetrahydrocannabinol (THC), the primary psychoactive component of cannabis, cross the placenta barrier. However, the consequences of prenatal cannabis use are not well understood, and less is known about potential combination effects when consumed with nicotine, especially via e-cigarettes.

OBJECTIVE

The present study used a rodent model to examine how prenatal e-cigarette exposure to nicotine, THC, and the combination impacts motor development among offspring.

METHODS

Pregnant Sprague-Dawley rats were exposed to nicotine (36 mg/mL), THC (100 mg/mL), the combination, or vehicle via e-cigarette inhalation from gestational days (GD) 5-20. One sex pair per litter was tested on an early sensorimotor development task (postnatal days [PD] 12-20) and a parallel bar motor coordination task (PD 30-32).

RESULTS

Combined prenatal exposure to nicotine and THC delayed sensorimotor development, even though neither drug produced impairments on their own. In contrast, prenatal exposure to either nicotine or THC impaired motor coordination, whereas combined exposure exacerbated these effects, particularly among females.

CONCLUSIONS

These data illustrate that prenatal exposure to either nicotine or THC may alter motor development, and that the combination may produce more severe effects. These findings have important implications for pregnant women as we better understand the teratogenic effects of these drugs consumed via e-cigarettes.

Association of Comorbid Behavioral and Medical Conditions With Cannabis Use Disorder in Pregnancy

IMPORTANCE

Prenatal cannabis use continues to increase, yet studies of the demographic, psychiatric, and medical characteristics associated with cannabis use in pregnancy are limited by size and use of self-report, and often do not consider cannabis use disorder (CUD) or concomitant substance use disorders (SUDs). Understanding the factors associated with CUD in pregnancy is paramount for designing targeted interventions.

OBJECTIVE

To examine the prevalence of co-occurring psychiatric and medical conditions of US pregnant individuals hospitalized with and without CUD by concomitant SUDs.

DESIGN, SETTING, AND PARTICIPANTS

The study analyzed restricted hospital discharge data from the 2010 to 2018 Healthcare Cost and Utilization Project State Inpatient Databases in 35 states. Data were analyzed from January to August 2021. Weighted linear regressions tested whether the prevalence of psychiatric and medical conditions differed between individuals with and without a CUD diagnosis at hospitalization. Inpatient hospitalizations of pregnant patients aged 15 to 44 years with a CUD diagnosis were identified. Pregnant patients aged 15 to 44 years without a CUD diagnosis were identified for comparison. Patients were further stratified based on concomitant SUD patterns: (1) other SUDs, including at least 1 controlled substance; (2) other SUDs, excluding controlled substances; and (3) no other SUDs.

EXPOSURES

CUD in pregnancy.

MAIN OUTCOMES AND MEASURES

Prevalence of demographic characteristics, psychiatric disorders (eg, depression and anxiety), and medical conditions (eg, epilepsy and vomiting).

RESULTS

The sample included 20 914 591 hospitalizations of individuals who were pregnant. The mean (SD) age was 28.24 (5.85) years. Of the total number of hospitalizations, 249 084 (1.19%) involved CUD and 20 665 507 (98.81%) did not. The proportion of prenatal hospitalizations involving CUD increased from 0.008 in 2010 to 0.02 in 2018. Analyses showed significant differences in the prevalence of almost every medical and psychiatric outcome examined between hospitalizations with and without CUD diagnoses, regardless of concomitant SUDs. Elevations were seen in depression (0.089; 95% CI, 0.083-0.095), anxiety (0.072; 95% CI, 0.066-0.076), and nausea (0.036; 95% CI, 0.033-0.040]) among individuals with CUD only at hospitalization compared with individuals with no SUDs at hospitalization.

CONCLUSIONS AND RELEVANCE

Considerable growth was observed in the prevalence of CUD diagnoses among individuals hospitalized prenatally and in the prevalence of depression, anxiety, nausea, and other conditions in individuals with CUD at hospitalization. This study highlights the need for more screening, prevention, and treatment, particularly in populations with co-occurring CUD and psychiatric disorders. Research on the determinants and outcomes associated with CUD during pregnancy is needed to guide clinicians, policy makers, and patients in making informed decisions.

US trends in the association of suicide ideation/behaviors with marijuana use among adolescents ages 12-17 and differences by gender and race/ethnicity

BACKGROUND

In the US over the past decade, there has been a steady increase in marijuana use rates among adolescents, in part due to marijuana legalization laws. It is unknown whether these greater marijuana use rates are associated with rising rates of adolescent suicide ideation and behaviors (plan and attempt) or whether these associations differ by gender or race/ethnicity.

OBJECTIVE

To determine whether marijuana use is associated with suicide ideation/behaviors among adolescents and if differences exist by gender and race/ethnicity.

MATERIALS AND METHODS

Using the 2015-2019 National Surveys on Drug Use and Health, we assessed the relationship between marijuana use frequency and suicide ideation/behaviors among adolescents (12-17, n = 73,986). We also examined the association with marijuana use disorder (MUD) and assessed differences by gender and race/ethnicity. Marijuana use frequency in the past year was categorized as no use, non-weekly use, and weekly-plus use. We estimated multivariable logistic regression models, adjusting for sociodemographics, health status, common co-occurring behavioral health disorders, and criminal history. For interpretability, regression coefficients were converted into predicted probabilities using predictive margin methods.

RESULTS

In primary analyses, adolescents with non-weekly use and weekly-plus use had higher rates of any suicide ideation, 61.5% (+ 10.4 percentage-points; 95% CI: 7.0-13.8%) and 64.5% (+ 13.4 percentage-points; 95% CI: 9.1-17.7%), relative to no use (51.1%). Non-weekly and weekly-plus use was associated with higher rates of any suicide plan 58.2% (+ 11.8 percentage-points; 95% CI: 7.8-16.0%) and 59.0% (+ 12.6 percentage-points; 95% CI: 6.4-18.9%), and any suicide attempt, 42.0% (+ 11.6 percentage-points; 95% CI: 7.0-16.2%) and 47.3% (+ 16.9 percentage-points; 95% CI: 10.9-22.9%) compared to no use (46.4 and 30.4%, respectively). Similar results were found among adolescents with a MUD (all p < 0.05). Positive associations between marijuana use and suicide ideation/behaviors persisted among males and females as well as White, Black, and Latinx adolescents (all p < 0.05).

CONCLUSION

Between 2015 and 2019, suicide ideation/behaviors increased for adolescents that used marijuana. As marijuana is legalized in more states, public health efforts are needed to curb increases in marijuana use among adolescents and to better understand the causal linkages between marijuana use and suicide ideation/behaviors.

Driving under the influence of cannabis risk perceptions and behaviour: A population-based study in Ontario, Canada

Driving under the influence of cannabis (DUIC) is detrimental to road safety. Risk perception is a strong determinant of DUIC behaviour, yet little is known about the factors influencing DUIC risk perception in the general population. The objective of this study was to identify factors associated with risk perceptions of motor vehicle collision and legal consequences due to DUIC and examine whether these perceptions were associated with DUIC behaviour. Data were derived from the 2017 CAMH Monitor, a cross-sectional telephone survey of adults aged 18+ years in Ontario, Canada (n = 1813). Multivariable logistic regression analyses were performed. Approximately 90% of adults overall agreed that DUIC increases motor vehicle collision risk compared to 55% of those reporting past-year DUIC. Being male, less educated, and using cannabis at least monthly were associated with disagreeing that DUIC increases motor vehicle collision risk. Being male, young, and using cannabis at least monthly were associated with agreeing that DUIC is safer than driving under the influence of alcohol (DUIA). Being male and using cannabis less than monthly were associated with agreeing that the chances of getting caught for DUIC are higher than DUIA. Safety but not legal risk perceptions were associated with DUIC behaviour among cannabis-using drivers. Cannabis legalization provides a timely opportunity for DUIC prevention strategies. This study suggests that policymakers should target male cannabis users and highlight the safety risks of DUIC. Further research is needed to assess the effectiveness of prevention measures and the impact of cannabis legalization on DUIC perceptions and behaviour.

Cannabis use disorder and dissociation: A report from a prospective first-episode psychosis study

BACKGROUND

Cannabis is the most used recreational drug worldwide. Its use can increase the risk of developing psychotic disorders and exacerbate their course. However, the relationship between cannabis use and dissociative symptoms has been scarcely investigated.

AIMS

To examine differences in psychotic and dissociative symptoms, and in functioning in first-episode psychotic patients (FEPp) using cannabis compared with those not using cannabis.

METHODS

Between January 2014 and December 2019, seventy FEPp with cannabis use disorder (N = 35) and without it (N = 35) were recruited in psychiatric inpatient facilities in the Italian regions of Lazio and Piemonte. All subjects were assessed at FEP, after 4 and 8 months, using the Positive and Negative Syndrome Scale (PANSS), the Global Assessment of Functioning (GAF) scale and the Dissociative Experiences Scale - II (DES-II). Detailed information on the pattern of cannabis and other substance use were collected.

RESULTS

FEP using cannabis showed higher levels of positive symptomatology, dissociative experiences and worse functioning than their non-user counterpart, despite a comparable antipsychotic treatment. At an eight-month prospective evaluation, FEP using cannabis still showed higher levels of positive symptomatology and dissociation. Moreover, global functioning worsened over time in FEPp using cannabis, whereas it improved those not using it.

DISCUSSION

Our findings suggest that a greater degree of dissociation and positive symptoms at FEPp and their persistence over time may characterise cannabis-associated psychosis. Both these factors might explain the overall functioning worsening over time that we observed in the cannabis-user group compared to the functioning improvement in the non-user group.

Young adult cannabis use disorder treatment admissions declined as past month cannabis use increased in the U.S.: An analysis of states by year, 2008-2017

OBJECTIVE

This short communication reports on the association of annual measures of young adult (age 18-24) past month cannabis use with cannabis use disorder (CUD) treatment admissions by state in the U.S. from 2008 to 2017.

METHODS

Annual data on percentage of past month cannabis use and the total number of CUD treatment admissions among young adults were acquired for each state from SAMHSA NSDUH and TEDS-A data sets. For each state, the correlation over time between cannabis use and treatment admissions rate was calculated and visualized in a choropleth map. Fixed-effects regression, where effects are fixed by state, was used to investigate the association of cannabis use with treatment admissions rate.

RESULTS

In 38 out of 50 states, including seven out of the eight states legalizing recreational cannabis during the study period, as young adult cannabis use increased, treatment admissions declined. Cannabis use is significantly and negatively associated with treatment admissions (β = -7.21, 95% CI = -11.88, -2.54), even after controlling for health insurance coverage, criminal justice referral, treatment center availability, and cannabis legalization status.

CONCLUSIONS

While it is possible that across the U.S. more young adults are using cannabis without developing CUD, we speculate that increasing social acceptance of cannabis use, and declining perception of harm, may influence treatment seeking behavior, potentially resulting in growing unmet need for CUD treatment among young adults. Monitoring state-level trends in cannabis use, CUD prevalence, and treatment admissions is key to developing CUD prevention and treatment policies targeted to timely, state-specific conditions.

County-Level Recreational Marijuana Policies and Local Policy Changes in Colorado and Washington State (2012-2019)

Policy Points In 2012, Colorado and Washington were the first states to legalize recreational marijuana through voter-initiated ballots. In these states, counties could restrict or ban local marijuana facilities through a variety of regulatory methods such as ordinances and zoning. County-level recreational marijuana policies in Washington and Colorado vary substantially, with 69.2% of Washington counties and 23.4% of Colorado counties allowing all types of recreational marijuana facilities as of April 1, 2019. After Colorado and Washington legalized recreational marijuana, many counties modified their marijuana policies over time, with shifts in county policy often preceded by advocacy and information-seeking activities.

CONTEXT

In 2012, Colorado and Washington were the first states to legalize recreational marijuana. Both allowed local governments to further regulate the availability of marijuana facilities in their jurisdictions. As early adopters, these states are important quasi-natural experiments to examine local marijuana policy and policy change processes, including key stakeholders and arguments.

METHODS

We conducted a policy scan of county-level recreational marijuana ordinances and regulations in Colorado and Washington. Data collected included policy documents from counties in both states and newspaper articles. We used a mixed-methods approach to describe the types of county-level recreational marijuana policies enacted by April 1, 2019; identify key policy stakeholders involved in local policy debates; and explore arguments used in support or opposition of county policies. We also selected four counties that represent three county policy environments (all marijuana facility types allowed, some marijuana facility types allowed, all marijuana facility types prohibited) and described the policy changes within these counties since recreational marijuana was legalized.

FINDINGS

By April 1, 2019, Colorado counties were less likely than Washington counties to allow marijuana facilities-48.4% of Colorado counties prohibited recreational marijuana facilities in their jurisdiction compared to 23.1% of Washington counties. Since state legalization, several counties in both states have made substantial marijuana facility policy modifications, often preceded by information-seeking activities. Primary stakeholders involved in policy debates included elected officials, law enforcement, individual growers/farmers, marijuana business license applicants, parents, and residents. Proponents referenced local economic gain, reduced crime, and potential health benefits of marijuana as arguments in favor of permitting local facilities, whereas opponents pointed to economic loss, negative health and public health issues, public safety concerns, and existing federal law. Both sides referenced local public opinion data to support their position.

CONCLUSIONS

By early 2019, a patchwork of local marijuana policies was in place in Colorado and Washington. We identify key areas of policy and public health research needed to inform future local marijuana policy decisions, including the impact of legalization on public health outcomes (particularly for youth) and public safety.

Cannabis use and misuse in the year following recreational cannabis legalization in Canada: A longitudinal observational cohort study of community adults in Ontario

BACKGROUND

Canada legalized cannabis for non-medical purposes federally in October 2018. This study examined changes in cannabis use over the following year in a sample of general community adults. A secondary aim was to examine forecasted cannabis use following legalization in relation to actual post-legalization cannabis use.

METHODS

Participants were 1502 community adults (61 % female; age M = 34.60 ± 13.95), with approximately half reporting any cannabis use in the six months prior to legalization (Cannabis+ group [48 %]/Cannabis- group [52 %]). Self-report assessments were conducted in the month before cannabis legalization, 6-months post-legalization and 12-months post-legalization. Primary outcomes were frequency of cannabis use, grams of dried flower cannabis on days used, and level of misuse (Cannabis Use Disorder Identification Test - Revised). Secondary analyses examined pre-legalization personal forecasts in relation to post-legalization cannabis use.

RESULTS

Statistically significant main effects of time (ps<.001), cannabis use status (ps<.001), and time × cannabis use status interactions (ps<.001) were present for cannabis frequency, quantity, and level of misuse. In each case, the interactions reflected significant decreases in the Cannabis+ group, but significant increases in the Cannabis- group. Approximately 15 % of participants erroneously forecasted their personal post-legalization cannabis use, with discrepancies most commonly being individuals who were not using prior to legalization subsequently using cannabis.

CONCLUSIONS

In this cohort of community adults, we observed significant changes over the first year following Canadian legalization, with divergent trajectories based on pre-legalization cannabis use. These findings suggest multifarious impacts of legalization in adults, with meaningfully different trajectories among subgroups.

A cross-national examination of cannabis protective behavioral strategies' role in the relationship between Big Five personality traits and cannabis outcomes

Background: Problematic cannabis use is common among young adults across the world. However, limited research has examined whether etiological models predicting negative consequences are universal.Objective: The present study examined whether the Five-Factor Model of personality (openness, conscientiousness, extraversion, agreeableness, and neuroticism) relates to cannabis outcomes via use of cannabis protective behavioral strategies (PBS) in a cross-national sample of college student cannabis users (i.e., used cannabis in the last 30 days).Method: Participants were 1175 university students (63.27% female) across five countries (United States, Argentina, Spain, Uruguay, and the Netherlands) recruited to complete an online survey.Results: PBS use mediated the associations between personality traits and cannabis consequences, such that higher conscientiousness (β = .20), agreeableness (β = .11), and lower emotional stability [i.e., higher neuroticism] (β = -.14) were associated with more PBS use. Higher PBS use was, in turn, associated with lower frequency of cannabis use (β = -.32); lower frequency of use was then associated with fewer cannabis consequences (β = .34). This sequential pathway was invariant across sex, but not countries. Notably, there were a number of differences in links between PBS and cannabis outcomes when comparing countries (e.g., negative associations in the US sample, but positive associations in the Argentina sample).Conclusions: Cannabis PBS mediates the relationship between personality traits and cannabis outcomes, but there are nuanced differences across countries (i.e., relationship between PBS and cannabis outcomes). Overall, students that are low in conscientiousness, agreeableness, and neuroticism and/or report low rates of PBS use may benefit from cannabis PBS-focused interventions that promote utilization of PBS.

Why Young Adults Obtain a Medical Marijuana Card: Associations with Health Symptoms and Heaviness of Use

Objective.

Prior studies documenting more frequent and problematic use among young adults who have acquired medical marijuana (MM) cards have broadly compared those who use medically to those who use recreationally. Gaining a better picture of how health symptoms and problematic use vary both within those who have a MM card for specific condition domains and between those who do not have a MM card can provide key information for medical practitioners and states interested in adopting or updating MM policies.

Method.

The current study categorizes young adults authorized to use MM into three mutually exclusive groups based on endorsements of qualifying conditions: (1) Physical Health only (e.g., AIDS, arthritis, cancer; n = 34); (2) Behavioral Health only (e.g., anxiety, depression, sleep problems; n = 75); and (3) Multiple Conditions (a physical and behavioral health condition; n = 71). Multiple and logistic regression models examined differences across marijuana use, problems, mental health, physical health, and sleep quality for MM condition categories and for those that only use marijuana recreationally (n = 1,015).

Results.

After adjusting for socio-demographic factors (age, sex, sexual orientation, educational status, employment status, race/ethnicity, mother’s education, prior intervention involvement in youth), MM card holders, particularly those with physical health or multiple health conditions, reported heavier, more frequent, and more problematic and risky marijuana use compared to those using recreationally. Despite this pattern, those in different MM condition categories were generally not found to be more symptomatic in domains of mental or physical health relevant to their respective conditions, compared to different category groups or to those using recreationally.

Conclusions.

Findings emphasize the importance of providers conducting a careful assessment of reasons for needing a card, along with use, to reduce potential harms while adding credibility to a medical movement with genuine promise of relief for many medical conditions.

The impact of state cannabis legislation, county-level socioeconomic and dog-level characteristics on reported cannabis poisonings of companion dogs in the USA (2009-2014)

With current trends in cannabis legalization, large efforts are being made to understand the effects of less restricted legislation on human consumption, health, and abuse of these products. Little is known about the effects of cannabis legalization and increased cannabis use on vulnerable populations, such as dogs. The objective of this study was to examine the effects of different state-level cannabis legislation, county-level socioeconomic factors, and dog-level characteristics on dog cannabis poisoning reports to an animal poison control center (APCC). Data were obtained concerning reports of dog poisoning events, county characteristics, and state cannabis legislation from the American Society for the Prevention of Cruelty to Animals’ (ASPCA) APCC, the US Census Bureau, and various public policy-oriented and government websites, respectively. A multilevel logistic regression model with random intercepts for county and state was fitted to investigate the associations between the odds of a call to the APCC being related to a dog being poisoned by a cannabis product and the following types of variables: dog characteristics, county-level socioeconomic characteristics, and the type of state-level cannabis legislation. There were significantly higher odds of a call being related to cannabis in states with lower penalties for cannabis use and possession. The odds of these calls were higher in counties with higher income variability, higher percentage of urban population, and among smaller, male, and intact dogs. These calls increased throughout the study period (2009–2014). Reporting of cannabis poisonings were more likely to come from veterinarians than dog owners. Reported dog poisonings due to cannabis appear to be influenced by dog-level and community-level factors. This study may increase awareness to the public, public health, and veterinary communities of the effects of recreational drug use on dog populations. This study highlights the need to educate dog owners about safeguarding cannabis products from vulnerable populations.

Driving-Related Behaviours, Attitudes and Perceptions among Australian Medical Cannabis Users: Results from the CAMS 18-19 Survey

As the use of cannabis for medical purposes becomes increasingly prevalent, driving under the influence of cannabis (DUIC) is emerging as a major public health issue. Understanding current behaviours, attitudes and perceptions around DUIC in medical cannabis users is an important first step in addressing this issue. Here we present the results from the driving-related subsection of the Cannabis as Medicine 2018-2019 Survey (CAMS18) of current Australian medical cannabis users (n = 1388). Of the 806 respondents who reported driving a motor vehicle in the last month, 34.6% said they typically drive within 3 hours of cannabis use, thereby risking DUIC, while more than 50% waited at least 7 hours before driving. A majority of respondents thought that their medical cannabis use did not affect their driving ability, and most denied any specific effects of cannabis on speeding, risk taking, reaction time, attentiveness or lane departures. A substantial majority (70.9%) felt confident in accurately assessing their own driving ability after using medical cannabis. Binary logistic regression showed that frequency of use and confidence to assess driving ability were strongly related to DUIC behaviour (i.e. driving soon after cannabis use). These results suggest a relatively high prevalence of DUIC and low perception of risk among this sample of medical cannabis users. Further research is needed to better understand the acute and chronic effects of medical cannabis use on driving and the relation between perceived and actual driving ability.

Seeking safety: a focus group study of young adults' cannabis-related attitudes, and behavior in a state with legalized recreational cannabis

BACKGROUND

Only July 1, 2017, Nevada became the fifth US state to allow the legal sale of recreational cannabis products for adults ages of 21 and over. This study investigates young adults' cannabis-related attitudes, perceptions, and behaviors in a state where recreational and medical cannabis use was recently legalized.

METHODS

We conducted 8 focus groups stratified by cannabis use (regular users, occasional users, and nonusers) with 32 college students ages 18 to 24. Data were analyzed using the inductive qualitative thematic analysis method.

RESULTS

Four themes emerged during analyses: "sort of legal," "mitigating harm through legalization," "Increasing acceptance," and "seeking safety when purchasing cannabis." Despite their limited knowledge of cannabis regulation, the majority of the participants supported recreational cannabis legalization from a harm reduction perspective. Most participants did not believe that cannabis legalization had affected their use behavior. However, participants, especially cannabis users, perceived that recreational cannabis legalization created a context where cannabis use was legally, socially, and behaviorally "safer" than in an illegal context, even for those below the legal age of sale.

CONCLUSIONS

Most studies focus on the role of perceived health risk on cannabis use. If there are population-level long-term effects of recreational cannabis legalization on use behavior, findings suggest that they will be mediated by the perceived legal, social, and behavioral risk of using cannabis.

An examination of relationships between cannabis legalization and fatal motor vehicle and pedestrian-involved crashes

OBJECTIVE

While attention has been given to how legalization of recreational cannabis affects traffic crash rates, there was been limited research on how cannabis affects pedestrians involved in traffic crashes. This study examined the association between cannabis legalization (medical, recreational use, and recreational sales) and fatal motor vehicle crash rates (both pedestrian-involved and total fatal crashes).

METHODS

We used crash data from the Fatality Analysis Reporting System (FARS) to calculate monthly rates of fatal motor vehicle crashes and fatal pedestrian-involved crashes per 100,000 people from 1991 to 2018. Changes in monthly crash rates in three states that had legalized cannabis (Colorado, Washington, and Oregon) were compared to matched control states using segmented regression with autoregressive terms.

RESULTS

We found no significant differences in pedestrian-involved fatal motor vehicle crashes between legalized cannabis states and control states following medical or recreational cannabis legalization. Washington and Oregon saw immediate decreases in all fatal crashes (-4.15 and -6.60) following medical cannabis legalization. Colorado showed an increase in trend for all fatal crashes after recreational cannabis legalization and the beginning of sales (0.15 and 0.18 monthly fatal crashes per 100,000 people).

CONCLUSIONS

Overall findings do not suggest an elevated risk of total or pedestrian-involved fatal motor vehicle crashes associated with cannabis legalization.

Marijuana Use Among Justice-Involved Youths After California Statewide Legalization, 2015-2018

Objectives. To determine the impact of California's recreational marijuana legalization on marijuana use among justice system-involved (JSI) adolescents and young adults, and to distinguish whether any changes resulted from legalization (passing the law) or from implementation of the law.Methods. We compared changes in JSI youths' marijuana use in 2 states: California (n = 504), where recreational marijuana use was recently legalized, and Pennsylvania (n = 478), where recreational use is still prohibited. Furthermore, we examined changes in marijuana use across 3 key time periods (October 2015-June 2018): before legalization, after legalization but before implementation, and after implementation.Results. California JSI youths did not demonstrate a significant increase in marijuana use after legalization (b = -0.010; P = .950) or implementation (b = -0.046; P = .846). However, in Pennsylvania, rates of marijuana use increased significantly after legalization (b = 0.602; P = .001) but not after implementation (b = 0.174; P = .533).Conclusions. Although recreational marijuana legalization was not associated with changes in marijuana use among youths in California, we observed increased rates of use in Pennsylvania after legalization in California. Recreational marijuana laws may be indirectly related to youths' marijuana use by supporting more permissive national attitudes toward marijuana.

Associations between Psychiatric Disorders and Cannabis-Related Disorders Documented in Electronic Health Records

Data from a large network of community health centers connected via a single electronic health record (EHR) system examined associations between psychiatric disorders and documentation of a cannabis-related disorder among patients with reported cannabis use. Participants were adults who had at least one ambulatory visit at a clinic in three states between 1/1/2012 and 12/31/2016 and had either 1) a documented cannabis-related disorder indicated by an ICD-9/10 code on the problem list or encounter list or 2) documentation of cannabis use in the EHR social history section. Clinics included 101,405 patients with either cannabis use recorded in the social history of the EHR (n = 71,660) or a cannabis-related disorder documented in the encounter or problem list (n = 29,745). GEE logistic regression modeling estimated adjusted odds ratios (aOR). Odds of patients having cannabis-related disorder recorded on the encounter or problem list were higher for individuals with depression (aOR = 1.08, 95% CI: 1.04-1.13), anxiety (aOR = 1.16, CI: 1.11-1.21) and bipolar disorder (aOR = 1.16, CI: 1.10-1.23). A diagnosis of schizophrenia increased the odds of a cannabis-related disorder by 62% (aOR = 1.62, CI: 1.48- 1.78). Primary care providers should routinely screen for and document cannabis-related disorders and psychiatric disorders.

E-cigarette use is prospectively associated with initiation of cannabis among college students

E-cigarettes have dramatically increased in popularity among youth. Coincident with expanded legalization, young adults' use of cannabis (marijuana) has also steadily increased in recent years. Use of tobacco products can increase the chances of later cannabis initiation among youth. However, most longitudinal investigations of tobacco and cannabis use patterns have focused on tobacco cigarettes, included adolescents as opposed to young adults, and have only employed two timepoints. The current study examined prospective associations between e-cigarette and cannabis use in a large, diverse college sample assessed over four timepoints (freshman - senior year; N = 4,670). E-cigarette use and cannabis use were modelled in a four-wave cross-lagged model. The results showed significant bidirectional associations between both substances, even after controlling for time-varying levels of depressive symptoms, alcohol use, and polysubstance use, sensation seeking, demographic variables, concurrent associations and previous levels of use. Moreover, the significance of the predictive path from e-cigarette use to later cannabis use remained unchanged when we ran the same model, but restricted the sample to e-cigarette-only users (i.e., never cigarette smokers), whereas only one prospective path from cannabis to e-cigarette use was significant in this subsample. The current findings suggest that the association of e-cigarette use and cannabis use is likely bidirectional, with stronger support for the link from e-cigarette use to later cannabis use, above and beyond cigarette use. As e-cigarettes gain further hold of the tobacco product market share and cannabis legalization continues to expand, data such as these will be critical for informing regulatory decisions for e-cigarettes and cannabis, particularly involving their accessibility to youth and young adults.

Assessing the public health impact of cannabis legalization in Canada: core outcome indicators towards an 'index' for monitoring and evaluation

The legalization of non-medical cannabis use and supply is impending in Canada. This constitutes a major policy change with the declared objective of improving public health outcomes, which requires rigorous monitoring and evaluation. While numerous different aspects associated with legalization will be examined, a focused perspective is required for effective policy evaluation purposes. To these ends, we have identified a set of 10 core indicators associated with cannabis-related risk/harm outcomes-based on current best evidence-that are expected to measure the primary impacts of legalization on public health outcomes. We briefly review these indicators, and their respective data availability in Canada. As ideally an integrated outcome assessment of cannabis legalization's impact on public health will be available, we further propose options to merge the individual indicators into an integrated, weighted 'index', considering their expected relative impact for public health. One possible approach to undertake this is 'multi-criteria decision analysis' as a method to weight the relative indicator impact on public health; alternative approaches are proposed. The integrated 'public health index' for cannabis legalization will allow for scientifically comprehensive, while focused, monitoring and evaluation of the effects of legalization in Canada for the benefits of science and evidence-based policy alike.

The impact of cannabis legalization in Uruguay on adolescent cannabis use

BACKGROUND

In 2013, Uruguay became the first country in the world to legalize recreational cannabis, instituting a non-commercial state regulatory model of production and supply. This study provides the first empirical evidence on its impacts on adolescent use of cannabis and related risks.

METHODS

We use a generalization of the synthetic control method (SCM) to estimate the impact of legalization in Uruguay on adolescent past year and month cannabis use, perceived availability of cannabis and perceived risk of cannabis use. We compare biennial high school student self-reported survey data from Montevideo and regions in the interior of Uruguay post-legalization (2014-2018) and post initial implementation (2015-2018) to a synthetic counterfactual constructed using a weighted combination of 15 control regions in Chile.

RESULTS

We find no evidence of an impact on cannabis use or the perceived risk of use. We find an increase in student perception of cannabis availability (58% observed vs. 51% synthetic control) following legalization.

CONCLUSION

Our findings provide some support for the thesis that Uruguay's state regulatory approach to cannabis supply may minimize the impact of legalization on adolescent cannabis use. At the same time, our study period represents a period of transition: pharmacy access, by far the most popular means of access, was not available until the summer of 2017. Additional study will be important to assess the longer-term impacts of the fully implemented legalization regime on substance use outcomes.

Personality Traits and Psychotic Proneness Among Chronic Synthetic Cannabinoid Users

OBJECTIVE

Chronic use of synthetic cannabinoids (SCs) has been associated with a wide range of negative consequences for health including psychotic and affective disturbances. Accumulating evidence indicates that cannabinoids use may be a risk factor for schizophrenia, and chronic natural cannabis users score higher than non-users on measures of schizotypal personality traits. However, little is known regarding the personality characteristics of SC users, especially in comparison with recreational cannabis users and healthy individuals. This study aimed to examine the differences in personality characteristics and schizotypy between SC users, regular cannabis users, and non-users and to compare these measures between groups.

METHODS

Forty-two chronic SC users, 39 natural cannabis users, and 47 non-using control participants, without history of mental disorder, or current substance use diagnosis (mean age 26± 4.47 years; 23 females, 105 males), completed the Big-Five Factor Inventory (BFI), the Schizotypal Personality Questionnaire-Brief (SPQ-B), substance use history, rating scales of depression and anxiety, and a demographic questionnaire.

RESULTS

On the BFI, SC users scored higher than natural cannabis users and non-users on neuroticism, but lower on agreeableness and extraversion, and endorsed greater schizotypal symptoms on the SPQ-B. In addition, SC users had lower scores on conscientiousness than non-users, and natural cannabis users were more extroverted than non-users. Higher openness and lower conscientiousness predicted schizotypy for both SC and natural cannabis users. Finally, greater neuroticism predicted schizotypy for natural cannabis users, and introversion predicted schizotypy for non-users.

CONCLUSIONS

These results show that chronic SC users differ from natural cannabis users and non-users on dimensions of specific personality traits and schizotypy that may indicate psychotic proneness.

Characteristics of Older Adults Who Were Early Adopters of Medical Cannabis in the Florida Medical Marijuana Use Registry

Use of medical marijuana is increasing in the United States and older adults are the fastest growing user group. There is little information about the characteristics and outcomes related to medical marijuana use. This study is a descriptive analysis of older adults (aged ≥50 years old) who were early adopters of a medical marijuana program in the U.S. state of Florida. Per state legislation, initial and follow-up treatment plans were submitted to the University of Florida College of Pharmacy. Data collection included demographics, clinical history, medical conditions, substance use history, prescription history, and health status. Follow-up treatment plans noted changes in the chief complaint and actions taken since the initial visit. Of the state's 7548 registered users between August 2016 and July 2017, N = 4447 (58.9%) were older adults. Patients utilized cannabidiol (CBD)-only preparations (45%), preparations that had both tetrahydrocannabinol (THC) and CBD (33.3%) or were recorded to use both CBD-only and THC + CBD products (21.7%). The chief complaints indicating medical cannabis treatment were musculoskeletal disorders and spasms (48.4%) and chronic pain (45.4%). Among other prescription medications, patients utilized antidepressants (23.8%), anxiolytics and benzodiazepines (23.5%), opioids (28.6%), and cardiovascular agents (27.9%). Among all drug classes with potential sedating effects, 44.8% of the cohort were exposed to at least one. Patients with follow-up visits (27.5%) exhibited marked improvement as assessed by the authorizing physicians. However, the patient registry lacked detailed records and linkable information to other data resources to achieve complete follow up in order to assess safety or efficacy. Future improvements to registries are needed to more adequately capture patient information to fill knowledge gaps related to the safety and effectiveness of medical marijuana, particularly in the older adult population.

The Effect of Marijuana Legalization on the Trajectories of Hard Drug–Related Hospitalizations: A Growth Curve Analysis of the County-Level State Inpatient Database in Washington, 2009–2015

Two antithetical arguments have raised controversies over the effect of recreational marijuana legalization on hard drug use. The gateway perspective posits that marijuana use diffuses hard drug use; however, recent studies argue that marijuana legalization displaces hard drug use. This study examines these conflicting arguments by investigating temporal patterns of hard drug–related hospitalizations (HDHs) before and after marijuana legalization. Using county-level State Inpatient Database data from Washington State for the years 2009–2015, along with other federal data sources, this study assesses temporal changes in HDH using growth curve modeling. Initial findings show support for the displacement perspective, though controlling for other county-level factors (education and economic change) indicates that the legalization of recreational marijuana may be a gateway toward harder drugs. Considering the economic situation of the United States during the study period, this study concludes that marijuana legalization functioned as a gateway toward increased hard drug use.

Potential Adverse Drug Events with Tetrahydrocannabinol (THC) Due to Drug-Drug Interactions

Tetrahydrocannabinol (THC) is the primary psychoactive ingredient in cannabis. While the safety of THC and cannabis has been extrapolated from millennia of recreational use, medical marijuana programs have increased exposure among medically complex individuals with comorbid conditions and many co-prescribed medications. Thus, THC should be recognized as a pharmacologically complex compound with potential for drug–drug interactions and adverse drug events. This review summarizes potential adverse drug events related to THC when combined with other medications. Metabolic drug–drug interactions are primarily due to THC conversion by CYP3A4 and CYP2C9, which can be impacted by several common medications. Further, CYP2C9 polymorphisms are highly prevalent in certain racial groups (up to 35% in Caucasians) and increase the bioavailability of THC. THC also has broad interactions with drug-metabolizing enzymes and can enhance adverse effects of other medications. Pharmacodynamic interactions include neurological effects, impact on the cardiovascular system, and risk of infection. General clinical recommendations for THC use include starting with low doses and titrating to desired effects. However, many interactions may be unavoidable, dose-limiting, or a barrier to THC-based therapy. Future work and research must establish sufficient data resources to capture medical marijuana use for such studies. Meanwhile, clinicians should balance the potential risks of THC and cannabis and the lack of strong evidence of efficacy in many conditions with patient desires for alternative therapy.

Understanding motivations for large US cannabis firms' participation in the cannabis space: Qualitative study exploring views of key decision-makers

INTRODUCTION AND AIMS

Large for-profit firms supply the majority of US state-legal cannabis stores and some firms have attempted to shape cannabis-related policies. Understanding firms' motivations for participation in the cannabis space is critical, given firms' possible links to cannabis usage patterns. Key decision-makers (KDM) in the cannabis space may have information unavailable to lower ranking staff, and may influence firm decision-making and consequently US cannabis usage practises. We present the findings of a qualitative study investigating the views of KDMs in the cannabis market, on large cannabis firms' motivations for participation in the space.

DESIGN AND METHODS

Data were collected through 37 semi-structured interviews with a convenience sample of KDMs in the US cannabis space, representing both for-profit and non-profit organisations. Thematic analysis, with an inductive approach, was used to analyse the data.

RESULTS

KDMs reported three non-exclusive motivations for large cannabis firms' participation in the space; to seek profit, to mitigate social inequity and to provide cannabis as medicine. Within the theme relating to profit, findings suggest that for-profit and non-profit organisations in the space may be cognisant of the other's goals, representing a symbiotic relationship.

DISCUSSION AND CONCLUSIONS

We suggest that firms may have reasons to enter the space not necessarily centred on increasing use. Although non-profits and for-profits have different agendas, the bottom line for both groups is to expand access. Policy-makers should be aware of that fact, and set policies which consider the two groups as a unified whole.

The use of cannabis and perceptions of its effect on fertility among infertility patients

STUDY QUESTION

What is the prevalence of cannabis use and the perceptions of its impact on fertility among infertility patients?

SUMMARY ANSWER

A total of 13% of infertility patients used cannabis within the last year, and current usage is associated with patient perceptions of negative effects of cannabis on fertility and pregnancy.

WHAT IS KNOWN ALREADY

Cannabis use is increasing among the general population and pregnant women, particularly in places where cannabis use is legal despite having known and potential negative effects on fertility and pregnancy.

STUDY DESIGN, SIZE, DURATION

A cross-sectional patient survey study was performed between July 2017 and September 2017. Patients attending a university-affiliated hospital-based fertility clinic (n = 290) were invited to complete a written survey. Inclusion criteria were limited to the ability to read English. There were no exclusion criteria.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Of the 290 patients approached, 270 (93%) agreed to participate. The questions covered demographics, cannabis usage, perceptions of the effect of cannabis on fertility and pregnancy, cessation of use due to infertility and personal history of disclosing cannabis use to healthcare providers (HCP).

MAIN RESULTS AND THE ROLE OF CHANCE

The results showed that 13% of respondents disclosed use of cannabis in the past year (past year users) and 38% had not used cannabis in the past year but had previously used cannabis (>1 year users) while 49% had never used cannabis (never users). Baseline demographics were similar for the three groups, but across four measures of fertility and pregnancy health, past-year users perceived less of a negative effect compared to >1 year users, and never users (P values of 0.02, 0.03, 0.01, <0.001 for questions on pregnancy, offspring health, male fertility and female fertility, respectively). Of past year users, 72% said they had or would disclose use to their HCP, but only 9.4% reported that their HCP had actually instructed them to discontinue use.

LIMITATIONS, REASONS FOR CAUTION

Self-reported patient surveys are subject to reporting bias and may not reflect actual use and perceptions.

WIDER IMPLICATIONS OF THE FINDINGS

This study suggests that cannabis use is common among infertility patients. Given the known negative impacts of cannabis on pregnancy, the authors would have expected informed infertility patients to cease cannabis use as part of their efforts to conceive. As the prevalence of cannabis use in the last year among infertility patients is similar to that in the general Canadian population, it is unclear whether the prevalence of cannabis use in the sample population merely reflects the average usage in society or, after taking into account those who reduced their usage to improve their fertility, is a factor contributing to infertility and thus prompting fertility referral. Given concern about the potential negative impact of cannabis use on fertility, and that only 9% of past year users had been instructed by an HCP to cease cannabis use, HCPs should consider the benefits of counselling about cannabis cessation for patients who are attempting to conceive. Future research should focus on analysing the effects of cannabis use on female fertility and determining whether a reduction in use among patients with infertility can improve conception rates.

STUDY FUNDING/COMPETING INTEREST(S)

Michelle Shin, Clinical Research Associate, is supported by the University of Toronto GREI Fellowship Fund, which is sponsored by unrestricted research grants from EMD Serono, Merck Canada and Ferring Pharmaceuticals. The authors have no potential conflicts of interest to disclose.

Association Between Recreational Marijuana Legalization in the United States and Changes in Marijuana Use and Cannabis Use Disorder From 2008 to 2016

IMPORTANCE

Little is known about changes in marijuana use and cannabis use disorder (CUD) after recreational marijuana legalization (RML).

OBJECTIVES

To examine the associations between RML enactment and changes in marijuana use, frequent use, and CUD in the United States from 2008 to 2016.

DESIGN, SETTING, AND PARTICIPANTS

This survey study used repeated cross-sectional survey data from the National Survey on Drug Use and Health (2008-2016) conducted in the United States among participants in the age groups of 12 to 17, 18 to 25, and 26 years or older.

INTERVENTIONS

Multilevel logistic regression models were fit to obtain estimates of before-vs-after changes in marijuana use among respondents in states enacting RML compared to changes in other states.

MAIN OUTCOMES AND MEASURES

Self-reported past-month marijuana use, past-month frequent marijuana use, past-month frequent use among past-month users, past-year CUD, and past-year CUD among past-year users.

RESULTS

The study included 505 796 respondents consisting of 51.51% females and 77.24% participants 26 years or older. Among the total, 65.43% were white, 11.90% black, 15.36% Hispanic, and 7.31% of other race/ethnicity. Among respondents aged 12 to 17 years, past-year CUD increased from 2.18% to 2.72% after RML enactment, a 25% higher increase than that for the same age group in states that did not enact RML (odds ratio [OR], 1.25; 95% CI, 1.01-1.55). Among past-year marijuana users in this age group, CUD increased from 22.80% to 27.20% (OR, 1.27; 95% CI, 1.01-1.59). Unmeasured confounders would need to be more prevalent in RML states and increase the risk of cannabis use by 1.08 to 1.11 times to explain observed results, indicating results that are sensitive to omitted variables. No associations were found among the respondents aged 18 to 25 years. Among respondents 26 years or older, past-month marijuana use after RML enactment increased from 5.65% to 7.10% (OR, 1.28; 95% CI, 1.16-1.40), past-month frequent use from 2.13% to 2.62% (OR, 1.24; 95% CI, 1.08-1.41), and past-year CUD from 0.90% to 1.23% (OR, 1.36; 95% CI, 1.08-1.71); these results were more robust to unmeasured confounding. Among marijuana users in this age group, past-month frequent marijuana use and past-year CUD did not increase after RML enactment.

CONCLUSIONS AND RELEVANCE

This study's findings suggest that although marijuana legalization advanced social justice goals, the small post-RML increase in risk for CUD among respondents aged 12 to 17 years and increased frequent use and CUD among adults 26 years or older in this study are a potential public health concern. To undertake prevention efforts, further studies are warranted to assess how these increases occur and to identify subpopulations that may be especially vulnerable.

A health promotion intervention to improve lifestyle choices and health outcomes in people with psychosis: a research programme including the IMPaCT RCT

Background

People with psychotic disorders have reduced life expectancy largely because of physical health problems, especially cardiovascular disease, that are complicated by the use of tobacco and cannabis.

Objectives

We set out to (1) chart lifestyle and substance use choices and the emergence of cardiometabolic risk from the earliest presentation with psychosis, (2) develop a pragmatic health promotion intervention integrated within the clinical teams to improve the lifestyle choices and health outcomes of people with psychosis and (3) evaluate the clinical effectiveness and cost-effectiveness of that health promotion intervention.

Design

We performed a longitudinal cohort study of people presenting with their first episode of psychosis in three mental health trusts and followed up participants for 1 year [work package 1, physical health and substance use measures in first episode of psychosis (PUMP)]. We used an iterative Delphi methodology to develop and refine a modular health promotion intervention, improving physical health and reducing substance use in psychosis (IMPaCT) therapy, which was to be delivered by the patient’s usual care co-ordinator and used motivational interviewing techniques and cognitive–behavioural therapy to improve health choices of people with psychosis (work package 2). We then conducted a multicentre, two-arm, parallel-cluster, randomised controlled trial to determine the clinical effectiveness and cost-effectiveness of using the intervention with people with established psychosis (work package 3: IMPaCT randomised controlled trial) in five UK mental health trusts. The work took place between 2008 and 2014.

Participants

All people aged between 16 and 65 years within 6 months of their first presentation with a non-organic psychosis and who were proficient in English were eligible for inclusion in the PUMP study. Participants in the work package 2 training development were staff selected from a range of settings, working with psychosis. Participants in the phase 3 Delphi consensus and manual development comprised three expert groups of (1) therapists/researchers recruited from the local and national community, (2) clinicians and (3) service users, each of whom took part in two iterative review and feedback sessions. For work package 3, IMPaCT randomised controlled trial, care co-ordinators in participating community mental health teams who were permanently employed and had a minimum of four eligible patients (i.e. aged between 18 and 65 years with a diagnosis of a psychotic disorder) on their caseload were eligible to participate. In studies 1 and 3, patient participants were ineligible if they were pregnant or had a major illness that would have had an impact on their metabolic status or if they had a significant learning disability. All participants were included in the study only after giving written confirmed consent.

Main outcome measures

Cardiometabolic risk markers, including rates of obesity and central obesity, and levels of glycated haemoglobin (HbA1c) and lipids, were the main outcomes in work package 1 (PUMP), with descriptive data presented on substance use. Our primary outcome measure for the IMPaCT randomised controlled trial was the physical or mental health component Short Form questionnaire-36 items quality-of-life scores at 12 months.

Results

Obesity rates rose from 18% at first presentation with psychosis to 24% by 1 year, but cardiometabolic risk was not associated with baseline lifestyle and substance use choices. Patterns of increase in the levels of HbA1c over the year following first presentation showed variation by ethnic group. We recruited 104 care co-ordinators, of whom 52 (with 213 patients) were randomised to deliver IMPaCT therapy and 52 (with 193 patients) were randomised to deliver treatment as usual, in keeping with our power calculations. Of these 406 participants with established psychosis, 318 (78%) and 301 (74%) participants, respectively, attended the 12- and 15-month follow-ups. We found no significant effect of IMPaCT therapy compared with treatment as usual on the physical or mental health component Short Form questionnaire-36 items scores at either time point in an intention-to-treat analysis [physical health score (‘d’) –0.17 at 12 months and –0.09 at 15 months; mental health score (‘d’) 0.03 at 12 months and –0.05 at 15 months] or on costs. Nor did we find an effect on other cardiovascular risk indicators, including diabetes, except in the case of high-density lipoprotein cholesterol, which showed a trend for greater benefit with IMPaCT therapy than with treatment as usual (treatment effect 0.085, 95% confidence interval 0.007 to 0.16; p = 0.034).

Limitations

Follow-up in work package 1 was challenging, with 127 out of 293 participants attending; however, there was no difference in cardiometabolic measures or demographic factors at baseline between those who attended for follow-up and those who did not. In work package 3, the IMPaCT randomised controlled trial, care co-ordinators struggled to provide additional time to their patients that was devoted to the health promotion intervention on top of their usual clinical care contact with them.

Conclusions

Cardiometabolic risk is prominent even soon after first presentation with psychosis and increases over time. Lifestyle choices and substance use habits at first presentation do not predict those who will be most cardiometabolically compromised 1 year later. Training and supervising care co-ordinators to deliver a health promotion intervention to their own patients on top of routine care is not effective in the NHS for improving quality of life or reducing cardiometabolic risk.

Future work

Further work is needed to develop and evaluate effective, cost-effective and affordable ways of preventing the emergence of and reversing existing cardiometabolic risk indicators in people with psychosis.

Trial registration

Current Controlled Trials ISRCTN58667926.

Funding

This project was funded by the National Institute for Health Research (NIHR) Programme Grants for Applied Research programme and will be published in full in Programme Grants for Applied Research; Vol. 8, No. 1. See the NIHR Journals Library website for further project information.

Mental Health and Medical Cannabis Use among Youth and Young Adults in Canada

Background: In October 2018, Canada became the second country to legalize non-medical cannabis. However, medical cannabis has been legally available in Canada since 2001 and, in 2015, approximately 800,000 Canadians reported using cannabis for medical purposes. Mental health is a common reason reported for using medical cannabis. Objectives: The current study examined perceived mental health among four groups: (1) Non/ex-users; (2) Recent non-medical users; (3) Recent unauthorized medical users; and (4) Recent authorized medical users. Methods: A total of 867 Canadian cannabis users and nonusers aged 16 to 30 were recruited through an online consumer panel in 2017, one year before non-medical cannabis legalization. Logistic and multinomial regression models were fitted to examine differences among cannabis use status and mental health measures. All estimates represent weighted data. Results: Self-reported emotional and mental health problems were higher among unauthorized (83.9%) and authorized medical cannabis users (83.2%) compared to non-medical users and non/ex-users (44.5% and 39.5%, respectively). Medical users were more likely to report using cannabis to manage or improve mental health problems than non-medical users (p < .001). There were few differences between unauthorized and authorized medical users, and between non/ex-users and non-medical users. Conclusions: The findings highlight a discrepancy between the recommendation that individuals with some mental health problems should avoid cannabis and the widespread practice of using cannabis to manage mental health. Education and reduced stigma around using cannabis after legalization in Canada may help address users coming forwards regarding use of cannabis for mental health problems.

Cortical surface morphology in long-term cannabis users: A multi-site MRI study

Cannabis exerts its psychoactive effect through cannabinoid receptors that are widely distributed across the cortical surface of the human brain. It is suggested that cannabis use may contribute to structural alterations across the cortical surface. In a large, multisite dataset of 120 controls and 141 cannabis users, we examined whether differences in key characteristics of the cortical surface - including cortical thickness, surface area, and gyrification index were related to cannabis use characteristics, including (i) cannabis use vs. non-use, (ii) cannabis dependence vs. non-dependence vs. non-use, and (iii) early adolescent vs. late adolescent onset of cannabis use vs. non-use. Our results revealed that cortical morphology was not associated with cannabis use, dependence, or onset age. The lack of effect of regular cannabis use, including problematic use, on cortical structure in our study is contrary to previous evidence of cortical morphological alterations (particularly in relation to cannabis dependence and cannabis onset age) in cannabis users. Careful reevaluation of the evidence on cannabis-related harm will be necessary to address concerns surrounding the long-term effects of cannabis use and inform policies in a changing cannabis regulation climate.

Association between cannabis use and sexual behavior among adolescents aged 12-15 years in 21 low- and middle-income countries

AIMS

To investigate the relationship between cannabis use and two sexual behaviors (ever had sex, multiple partners) in a large representative sample of adolescents aged 12-15 years from 21 low- and-middle income countries.

METHODS

Data from 84,867 adolescents aged 12-15 years participating in the Global School-based Student Health Survey were analyzed. Participants reported lifetime frequency of cannabis use (analyzed as 0, 1-2, 3-19 or ≥ 20 times), whether they had ever had sexual intercourse (yes/no) and, if yes, their lifetime number of sexual partners. We used multivariable logistic regression to analyze associations, adjusting for a range of relevant covariates.

RESULTS

12.7% of the sample reported having had sexual intercourse, and of these adolescents, 53.1% had had multiple sexual partners. The prevalence of lifetime cannabis use of 1-2 times, 3-19 times, and ≥ 20 times were 1.1%, 1.2%, and 0.4%, respectively. Those who reported using cannabis 1-2 times, 3-9 times, and ≥ 20 times had 2.32 (95%CI = 1.47-3.65), 2.34 (95%CI = 1.34-4.07), and 5.45 (95%CI = 2.22-13.40) times higher odds of having had sexual intercourse than those who had never used cannabis. Among those who had ever had sexual intercourse, the respective odds ratios (95%CIs) for having multiple sexual partners were 1.56 (0.93-2.62), 1.70 (0.92-3.14), and 5.66 (2.97-10.82). There were no significant interactions by sex for these associations.

CONCLUSIONS

Adolescents from LMIC who use cannabis are more likely to have ever had sexual intercourse than those who do not. Among those who have had sexual intercourse, those who use cannabis are more likely to have had multiple sexual partners.