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Introduction: Socioeconomic disadvantage has been associated with cannabis use and poor mental health. It is therefore hypothesised that lower maternal education, a proxy for socioeconomic disadvantage, may increase the risk of cannabis-related mental health and substance use consequences., Methods: A total of 5099 participants from the Avon Longitudinal Study of Parents and Children reported cannabis use via questionnaires at 16 or 18. Logistic regression was used to examine the relationship between any and regular (weekly or more) adolescent cannabis use with depression, anxiety, psychotic experiences, and problematic cannabis use at age 24. Maternal education was included as an effect modifier. Missing data were addressed through multiple imputation using chained equations., Results: In total, 36.5% of participants reported adolescent cannabis use and, of these, 14% reported regular use. Adolescent cannabis use was associated with an increased likelihood of anxiety and problematic cannabis use; however, there was little evidence of moderation by maternal education. Regular cannabis use was associated with an increased likelihood of problematic cannabis use, with little evidence of moderation by maternal education. There was weak evidence that the association between regular cannabis use and depression (interaction p-value = 0.024) and anxiety (interaction p-value = 0.056) was stronger in people with high maternal education., Discussion and Conclusions: Adolescent cannabis use is associated with increased risk of anxiety and cannabis use disorder, but there was insufficient evidence that childhood socioeconomic position (proxied by maternal education) modifies this relationship. Improved public health messages for all adolescents about these risks may be warranted., (© 2024 The Author(s). Drug and Alcohol Review published by John Wiley & Sons Australia, Ltd on behalf of Australasian Professional Society on Alcohol and other Drugs.)

Aims: To estimate the strength of association between psychiatric disorders and substance use disorders (SUD), and cannabis use and cannabis use disorder (CUD) during early pregnancy., Design: Observational study., Setting: Kaiser Permanente Northern California, USA., Participants: 299 496 pregnancies from 227 555 individuals screened for cannabis use by self-report and a urine toxicology test at entrance to prenatal care in Kaiser Permanente Northern California during January 2011-December 2021 (excepting year 2020). The sample was 62.5% non-White, with a mean (standard deviation) age of 31.1 (5.5) years; 6.8% used cannabis; 0.2% had a CUD., Measurements: Exposure variables included electronic health record-based psychiatric diagnoses of attention deficit hyperactivity, anxiety, bipolar, depressive, personality, posttraumatic stress and psychotic disorders; and alcohol, opioid, stimulant and tobacco use disorders, during the two years prior to pregnancy up to the day before the prenatal substance use screening date. Outcome variables were any cannabis use, frequency of self-reported cannabis use and CUD during early pregnancy., Findings: Psychiatric disorder prevalence ranged from 0.2% (psychotic) to 14.3% (anxiety), and SUD ranged from 0.3% (stimulant/opioid) to 3.8% (tobacco). Psychiatric disorders were associated with cannabis use and CUD, with the strongest association for any use found for bipolar disorder (adjusted odds ratio [aOR] = 2.83; 95% confidence interval [CI] = 2.53-3.17) and the strongest association for CUD found for psychotic disorders (aOR = 10.01, 95% CI = 6.52-15.37). SUDs were associated with cannabis use and CUD, with the strongest association for any use found for tobacco use disorder (aOR = 4.03, 95% CI = 3.82-4.24) and the strongest association for CUD found for stimulant use disorder (aOR = 21.99, 95% CI = 16.53-29.26). Anxiety, bipolar, depressive disorders and tobacco use disorder were associated with greater odds of daily than monthly or less cannabis use., Conclusions: Psychiatric disorders and substance use disorders appear to be associated with elevated odds of any and frequent cannabis use as well as cannabis use disorder during early pregnancy. In most cases, the associations with cannabis outcomes were stronger for substance use disorders than other psychiatric disorders., (© 2024 Society for the Study of Addiction.)

Background and Objectives: The use of both electronic and combustible cigarettes is related to greater rates of cannabis use. Further, cannabis use is associated with worse combustible smoking-related outcomes, yet little research has identified mechanisms underlying such relations. It may be that negative-affect-related transdiagnostic factors such as emotion dysregulation, anxiety sensitivity, and/or distress intolerance play a mechanistic role in the cannabis-tobacco interrelations., Methods: The current study tested this hypothesis among 400 adults who endorsed dual use, 33% of whom endorsed current (past 3 months) cannabis use. We conducted analyses of variance and indirect effects model using the PROCESS v4.1 macro in SPSS version 29., Results: Results indicated that participants who use cannabis reported greater difficulty with emotion regulation, anxiety sensitivity, and cigarette dependence severity. Cannabis use was related to cigarette dependence severity indirectly via difficulty with emotion regulation and anxiety sensitivity., Discussion and Conclusions: These results indicate that specific transdiagnostic negative-affect-related factors of difficulty with emotion regulation and anxiety sensitivity are associated with cannabis use among adults who smoke combustible and electronic cigarettes., Scientific Significance: Given that these transdiagnostic factors are malleable, these findings suggest targeting and engaging such mechanisms may offer novel behavioral change strategies for this high-risk population., (© 2024 The American Academy of Addiction Psychiatry (AAAP).)

Background and Aims: Multiple countries are considering revising cannabis policies. This study aimed to measure long-term trends in cannabis use in the United States and compare them with alcohol use., Design and Setting: Secondary analysis of United States general population survey data., Participants: The national surveys had a total of 1 641 041 participants across 27 surveys from 1979 to 2022., Measurements: Rates of use reported to the US National Survey on Drug Use and Health and its predecessors are described, as are trends in days of use reported. Four milepost years are contrasted: 1979 (first available data and end of relatively liberal policies of the 1970s), 1992 (end of 12 years of conservative Reagan-Bush era policies), 2008 (last year before the Justice Department signaled explicit federal non-interference with state-level legalizations) and 2022 (most recent data available)., Findings: Reported cannabis use declined to a nadir in 1992, with partial recovery through 2008, and substantial increases since then, particularly for measures of more intensive use. Between 2008 and 2022, the per capita rate of reporting past-year use increased by 120%, and days of use reported per capita increased by 218% (in absolute terms from the annual equivalent of 2.3 to 8.1 billion days per year). From 1992 to 2022, there was a 15-fold increase in the per capita rate of reporting daily or near daily use. Whereas the 1992 survey recorded 10 times as many daily or near daily alcohol as cannabis users (8.9 vs. 0.9 M), the 2022 survey, for the first time, recorded more daily and near daily users of cannabis than alcohol (17.7 vs. 14.7 M). Far more people drink, but high-frequency drinking is less common. In 2022, the median drinker reported drinking on 4-5 days in the past month, versus 15-16 days in the past month for cannabis. In 2022, past-month cannabis consumers were almost four times as likely to report daily or near daily use (42.3% vs. 10.9%) and 7.4 times more likely to report daily use (28.2% vs. 3.8%)., Conclusions: Long-term trends in cannabis use in the United States parallel corresponding changes in cannabis policy, with declines during periods of greater restriction and growth during periods of policy liberalization. A growing share of cannabis consumers report daily or near daily use, and their numbers now exceed the number of daily and near daily drinkers., (© 2024 The Author. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.)

Background and Objectives: Cannabis use is highly prevalent among individuals with a history of intimate partner violence (IPV) and among people who drink alcohol. Motives for cannabis use are important correlates of consumption and problem severity. However, no research has examined cannabis use motives among couples with IPV. The goals of the study were to examine (1) the associations between a person and their partner's cannabis use motives; and (2) examine the extent to which each partners' cannabis use motives are related to their own and their partner's cannabis consumption., Methods: Participants were 100 couples (n = 92 different-sex couples, n = 8 same-sex couples) who reported physical IPV in their current relationship., Results: Certain cannabis motives (coping and conformity) and behaviors (cannabis use frequency, quantity and drug-related problems) were positively associated between intimate partners. One's own higher coping motives were associated with greater frequency of cannabis consumption; higher conformity motives were associated with less quantity of consumption; higher social motives were associated with greater quantity of cannabis consumption; and one's partner's social motives were associated with less quantity of cannabis consumption. DISCUSSION AND CONCLUSIONS: Findings suggest that couples report similar motives for cannabis use, and that one's own and their partner's motives may differentially influence frequency and quantity of use., Scientific Significance: This study provides novel information on congruency between cannabis use motives and behaviors between intimate partners, as well as how both an individual and their partner's motives for use can influence an individual's cannabis use behaviors., (© 2024 The American Academy of Addiction Psychiatry (AAAP).)

Guided by General Theory of Crime and Psychosocial Maturity Hypothesis, we investigated co-development between short-term mindsets (impulsivity and future orientation) and risk behaviors (cannabis use and delinquency). Parallel process latent growth modeling on three-wave data from ethnically diverse Swiss adolescents (N = 1365; M age 13.67 years, 48.6% female), showed baseline-level associations between short-term mindsets and risk behaviors, and between the two risk behaviors. Additionally, correlated change (co-development) existed between short-term mindsets-particularly impulsivity-and delinquency, but not between short-term mindsets and cannabis use. These results support the above-mentioned theories and emphasize the importance of investigating the correlates of change in delinquency and cannabis use separately, as divergent findings might emerge. These divergent findings could partially stem from Switzerland's liberal views on cannabis use., (© 2024 The Author(s). Journal of Research on Adolescence published by Wiley Periodicals LLC on behalf of Society for Research on Adolescence.)

Background and Aims: High-potency cannabis has been associated with increased risk of psychosis, but a lack of prospective data hinders understanding of causality in this relationship. This study aimed to combine prospective report of cannabis use with retrospective report of potency to infer the potency of cannabis used in adolescence and explore whether use of cannabis, and the use of high-potency cannabis, in adolescence is associated with incident psychotic experiences., Design: Population-based birth cohort study., Setting: United Kingdom., Participants: n = 5570 participants who reported on any cannabis use (yes/no) age 16 and 18 years, and n = 1560 participants from this group who also retrospectively reported on cannabis potency., Measurements: In questionnaires at ages 16 and 18, individuals self-reported lifetime cannabis use, and at age 24, participants reported the type of cannabis they most commonly used in the whole time since first using cannabis. Psychotic experiences were assessed at age 24 years using the semi-structured Psychosis-Like Symptom Interview, with incident defined as new-onset occurring between ages 19 and 24 years., Findings: Use of high-potency cannabis at age 16 or 18 was associated with twice the likelihood of experiencing incident psychotic experiences from age 19-24 (Odds Ratio 2.15, 95% Confidence Intervals 1.13-4.06). There was less evidence for an effect of any cannabis use on incident psychotic experiences (Odds Ratio 1.45, 95% Confidence Intervals 0.94-2.12)., Conclusions: Use of high-potency cannabis appears to be associated with increased likelihood of psychotic experiences., (© 2024 The Authors. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.)

Background and Objectives: Limited longitudinal research has examined differential interpersonal and intrapersonal correlates of young adult use and use frequency of cigarettes, e-cigarettes, and cannabis. This study aimed to address these limitations., Methods: We analyzed five waves of longitudinal data (2018-2020) among 3006 US young adults (M age  = 24.55, 44% male, 32% sexual minority, ~30% racial/ethnic minority). Two-part latent growth models examined likelihood of past-month cigarette, e-cigarette, and cannabis use (binary part) and days used (continuous part) and identified predictors (depressive symptoms, personality traits, adverse childhood experiences [ACEs], parental use) of baseline use and changes over time., Results: Regarding baseline past-month use (27% cigarettes, 38% e-cigarettes, 39% cannabis), depressive symptoms, ACEs, and parental substance use predicted use outcomes (i.e., likelihood, frequency) for each product; extraversion predicted cigarette and e-cigarette use outcomes; openness predicted e-cigarette and cannabis use outcomes; conscientiousness negatively predicted cigarette and cannabis use outcomes; and agreeableness negatively predicted cannabis use frequency. Regarding longitudinal changes, conscientiousness predicted accelerated increase of cigarette use frequency at later timepoints; depressive symptoms predicted increases in likelihood of e-cigarette use but the association weakened over time; and parental cannabis use predicted decreased cannabis use frequency but the association weakened over time., Discussion and Conclusions: Young adult substance use interventions should target high-risk subgroups and focus on distinct factors impacting use, including chronic, escalating, and decreasing use., Scientific Significance: This study advances the literature regarding distinct predictors of different substance use outcomes and provides unique data to inform interventions targeting young adult cigarette, e-cigarette, and cannabis use., (© 2024 The American Academy of Addiction Psychiatry (AAAP).)

Background and Aims: Cannabis and nicotine (tobacco or e-cigarettes) use commonly co-occurs and understanding their relationship can help to inform public health strategies to prevent their harms. We conducted a systematic review and meta-analysis to estimate the association of cannabis use given prior nicotine use and vice versa., Methods: PubMed, Embase, PsycINFO, Google Scholar and a hand-search were conducted in 2023 for longitudinal studies of the general population with no restrictions in settings (locations). Random-effects meta-analysis was conducted to estimate odds ratios between cannabis and nicotine use in both directions. The impact of unmeasured confounding was assessed using E-values., Results: From 5387 identified records, we included 20 studies. Among cannabis-naïve youths, baseline use of any nicotine products was positively associated with initiation of any cannabis use at follow-up [odds ratio (OR) = 5.39, 95% confidence interval (CI) = 3.19, 9.11; adjusted OR (aOR) = 2.59, 95% CI = 2.01, 3.32]. In nicotine-naïve participants (youths + adults), baseline cannabis use was positively associated with the initiation of any nicotine use at follow-up (OR = 4.08, 95% CI = 2.05, 8.11; aOR = 2.94, 95% CI =1.54, 5.61). There were no significant associations between baseline cannabis use and subsequent initiation of any nicotine (aOR = 3.29, 95% CI = 0.85, 12.76) or daily nicotine use (aOR = 2.63, 95% CI = 0.41, 16.95) among youths. The median E-values were 5.5 for nicotine exposure and cannabis use initiation and 4.1 for cannabis exposure and nicotine use initiation, indicating that substantial unmeasured confounding would need to have a strong association with both outcomes to fully explain away the cannabis and nicotine relationship., Conclusion: Although the evidence for associations between cannabis use and tobacco use is mixed, a majority of studies to date have found that cannabis use is associated with prior nicotine use and vice versa., (© 2024 The Author(s). Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.)

Background and Objectives: Recent studies suggest a growing trend in marijuana use, compared to a stable prevalence of marijuana use disorder among US adults over the first 15 years of the 21st century. This study investigated the recent patterns of marijuana use disorder among people with disabilities (PWD)., Methods: We extracted a nationally representative sample (N = 209,058) from the 2015-2019 National Survey on Drug Use and Health data set and examined associations by functional disability status (any disability, disability by type, and number of disabling limitations) with marijuana use disorder using a series of independent multivariable logistic regression models. We also performed trend analyses during the study period., Results: The prevalence of marijuana use disorder (from 1.7% to 2.3%) increased significantly among PWD between 2015 and 2019 (p-trend < .001). PWD were significantly more likely to report marijuana use disorder (odds ratio [OR], 1.37, 95% confidence interval [CI], 1.24-1.52) than people without disability (PWoD). Those with cognitive limitation only (OR, 1.78, 95% CI, 1.53-2.06) and ≥2 limitations (OR, 1.29, 95% CI, 1.10-1.51) were more likely to report marijuana use disorder than PWoD., Discussion and Conclusions: PWD had a consistently higher prevalence of marijuana use disorder than PWoD. Additionally, the level of risk for marijuana use disorder varied by disability type and number of disabling limitations., Scientific Significance: Our study provided new nuance on disparities in marijuana use disorder between PWD and PWoD and further revealed the varied risks for marijuana use disorder across different disability statuses., (© 2023 The American Academy of Addiction Psychiatry (AAAP).)

Background and Objectives: American Indian (AI) adolescents report higher rates of cannabis use than national US adolescents. Previous study examined interactive relationships between depressed affect and family factors on AI adolescent alcohol use. These factors have not been investigated for cannabis use. We examined whether parental monitoring dampened risk for cannabis use due to depressed affect, and potential moderation by sex., Methods: We measured cannabis use, depressed affect, parental monitoring, and sex among reservation area AI youth among students in grades 7-12 attending 45 schools. We used censor-inflated regression models to identify parental monitoring as a moderator of the relationship between depressed affect and cannabis use., Results: In the logistic portion of censor-inflated models, level of depressed affect and parental monitoring significantly related to last 30-day cannabis use. Higher levels of parental monitoring at lower levels of depressed affect related to lower likelihood of cannabis use. Female students had greater likelihood of endorsing cannabis use at higher levels of depressed affect. In the linear portion of the censor-inflated regression models, sex and level of parental monitoring significantly related to cannabis use frequency. Male students endorsed more frequent cannabis use while higher levels of parental monitoring related to lower frequency of use., Discussion and Conclusions: Parental monitoring may dampen the effect of depressed affect on cannabis use among AI youth on reservations., Scientific Significance: Future interventions should foster skill-building prevention efforts directed at coping with depression, along with parental training for effective monitoring. Special attention to AI female adolescents may be indicated., (© 2023 The Authors. The American Journal on Addictions published by Wiley Periodicals LLC on behalf of The American Academy of Addiction Psychiatry (AAAP).)

Aims: To measure longitudinal trajectories of marijuana use in four tobacco/nicotine products (hand-rolled cigarettes/spliffs, cigars/blunts, hookah, and e-cigarettes) among young adult Texas college students from 2015 to 2019., Design: This study used six consecutive waves of data from the marketing and promotions across colleges in Texas project (Project M-PACT), a longitudinal study of the tobacco behaviors of young adult college students. The first four waves were collected every 6 months (fall 2015-spring 2017), and the final two waves were conducted yearly (spring 2018 and 2019). Growth curve models measured trajectories of marijuana use in tobacco products across the 3.5-year period., Setting and Participants: A total of 4857 young adults from 24 colleges in the largest metropolitan areas of Texas, United States (Austin, Dallas, Houston, and San Antonio): mean age = 21.0, SD = 2.3; 64.2% assigned female; 36.1% non-Hispanic white, 31.0% Hispanic, and 33.0% other or combination race/ethnicity., Measurements: Participants completed online surveys assessing their past 6-month use of marijuana in four tobacco products of interest (spliffs, blunts, hookah, and e-cigarettes) and socio-demographic variables (sex, race/ethnicity, age, 2-year/4-year college attendance, and sexual and gender minority identity)., Findings: Observed vaping marijuana in e-cigarettes approximately doubled between the spring of 2015 and the spring of 2019, from 11.8% to 23.9% following a quadratic time trend (linear OR = 0.84, 95% CI = 0.73-0.97, quadratic OR = 1.18, CI = 1.13-1.22). This same time period saw a quadratic decline in using marijuana in hookah (P < 0.001) and no changes in using hand-rolled cigarettes/spliffs or cigars/blunts for marijuana delivery., Conclusions: The popularity of nicotine e-cigarettes appears to be expanding the avenues for marijuana delivery among young adults in Texas, United States., (© 2022 Society for the Study of Addiction.)

Aims: To estimate the effect of recreational legalization on cannabis use frequency and sources of variance across legal environments., Design: Longitudinal discordant twin and gene-environment interaction models in twins recruited from birth records and assessed prospectively., Setting: The United States, including states with different recreational cannabis policies before and after 2014, when recreational cannabis was first legalized., Participants: Two longitudinal, prospectively assessed samples of American twins aged 24-47 (n = 1425 in legal states, n = 1996 in illegal states), including 111 monozygotic pairs discordant for residence., Measurements: Current cannabis use frequency (measured continuously and ordinally) was the primary outcome, and the predictor was recreational status of cannabis (legal/illegal) in the participant's state of residence at the time of assessment. Covariates include age, sex and cannabis use frequency prior to 2014., Findings: Accounting for pre-2014 use, residents of legal states used cannabis more frequently than residents of illegal states (b = 0.21, P = 8.08 × 10 -5 ). Comparing 111 pairs of monozygotic twins discordant for residence confirmed the effect (b = 0.18, P = 0.014). There was inconclusive evidence for genetic influences on cannabis use frequency that were specific to the legal environment [χ 2  = 2.9 × 10 -9 , degrees of freedom (d.f.) = 1, P > 0.999]. Existing genetic influences were moderated by the legal environment, as the genetic correlation between marijuana use before and after legalization was lower in states that legalized (r genetic  = 0.24) compared with states that did not (r genetic  = 0.78, P difference  = 0.016)., Conclusions: In the United States, there appears to be a ~ 20% average increase in cannabis use frequency attributable to recreational legalization, consistent across increasingly rigorous designs. In addition, the heritability of cannabis use frequency appears to be moderated by legalization., (© 2022 The Authors. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.)

Background and Objectives: Individuals with chronic lower back pain (CLBP) report using alcohol and marijuana to cope with pain. Little research has tested whether co-use is associated with worse psychological outcomes., Methods: Participants had CLBP and past-month alcohol/marijuana co-use (n = 192), alcohol use (n = 148), marijuana use (n = 78), or no use (n = 101)., Results: Co-use was associated with more drinking-related problems, anxiety, and pain anxiety compared to alcohol-(but not marijuana-) only, whereas marijuana-only use was associated with worse psychological outcomes than alcohol use-only; effect sizes were small to medium., Discussion and Conclusions: Co-use and marijuana-only were associated with worse outcomes than alcohol-only., Scientific Significance: The present findings extend current understanding of co-use by finding that marijuana use among people with CLBP (a group with especially high rates of use of these substances) is associated with worse alcohol-related problems and psychological outcomes., (© 2022 The American Academy of Addiction Psychiatry (AAAP).)

Background and Aims: To estimate during pregnancy correlations between frequency of self-reported use of marijuana and quantified marijuana metabolite in biospecimens including urine, sera and umbilical cord homogenate., Design: Prospective cohort., Setting: Two urban hospitals in Colorado with legal recreational and medicinal marijuana., Participants: Pregnant women (<16 weeks gestation) self-reporting marijuana use., Measurements: Participants completed a written self-report survey and provided biospecimens at <16 weeks gestation (n = 46), 18 to 22 weeks gestation (n = 43), 32 to 36 weeks gestation (n = 39), and delivery (n = 37). Self-reported marijuana use frequency was calculated based on past-month days of use multiplied by number of daily uses. Maternal urine and sera were tested for presence (>5 ng/mL) of 11-nor-9-carboxy-delta-9-tetrahydrocannabinol (THC-COOH). Liquid chromatography tandem mass spectrometry quantified THC-COOH in umbilical cord homogenate (ng/g). Last marijuana use by any measure was recorded to evaluate the time frame over which THC-COOH remains detectable (>0.10 ng/g) in cord., Findings: From December 2017 through May 2019, 51 pregnant women enrolled, and 46 were included in analyses (2 withdrew and 3 had a spontaneous abortion). The majority were normal weight, White or Black race, and insured by Medicaid. At the time of enrollment between 7 to 15 weeks' gestation, 87% had ongoing use by self-report, or positive urine or serum. The majority (33 [66%]) stopped using before delivery. Sera and urine results were strongly correlated with self-reported use frequency (Spearman correlation coefficient [r] range 0.70-0.87 across visits, P < 0.001), and with each other. There was only one positive cord result when use stopped before 22 weeks. Frequency of self-reported marijuana use at delivery had strong correlation with quantified cord THC-COOH (r = 0.80, 95% CI = 0.62-0.89)., Conclusions: Quantified umbilical cord THC-COOH appears to strongly correlate with frequency of maternal marijuana use in the last month of pregnancy. Earlier use can be measured by either quantitative urine or serum assay., (© 2021 Society for the Study of Addiction.)

Background: The reasons for college students to abstain from alcohol and cannabis use on a given day can inform efforts to prevent or intervene in those behaviors. Research on reasons for alcohol nonuse remains in its nascent stages and no study to date has examined reasons for cannabis nonuse on a given day. Here we examine reasons for nonuse among college students after they planned to use alcohol and/or cannabis., Methods: College students (N = 341; M age  = 19.79; 53% women; 74% White) from 3 universities completed 54 days of data collection across which approximately 50% were nonuse days. Each morning, participants indicated whether they planned to use that day; nonuse reasons were assessed the next morning, if applicable. Generalized linear mixed-effects models were used to disentangle within- and between-person effects., Results: On a given nonuse day (at the within-person level), "work" and "school" were reasons associated with having no plan to use alcohol and "to feel in control" was linked to having no plan to use cannabis. "Did not want to get high" was related to forgoing plans (did not use when originally planned) for alcohol use at the within-person level. At the between-person level, "no desire" was associated with no plans for alcohol or cannabis use and "did not want to get high" was related to no plans for cannabis use. "School" and "could not get" were related to forgoing plans for alcohol and cannabis use, respectively, at the between-person level., Conclusion: An examination of earlier intentions for alcohol and/or cannabis use on nonuse days yielded novel findings on the intention-behavior gap. Reasons for nonuse can inform intervention and prevention strategies (e.g., those involving social norms or just-in-time adaptive efforts) for alcohol and cannabis use on college campuses., (© 2021 by the Research Society on Alcoholism.)

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., (© 2021 by the Research Society on Alcoholism.)

Introduction and Aims: Simultaneous alcohol and marijuana (SAM) use is reported by roughly 30% of young adult drinkers. Among SAM users, SAM use days have more negative substance-related consequences than single-substance days. Little information is available about contextual factors contributing to the likelihood of SAM use on a particular day. This study compared days on which individuals reported SAM use relative to days on which they reported alcohol but not marijuana use in terms of physical location, engagement in risky activities and social context of use., Design and Methods: Participants were 148 young adults (57% female) reporting past-month SAM use and past two-week binge drinking. Participants completed up to 14 daily surveys assessing substance use behaviour and socio-environmental characteristics of use., Results: For those <21 years, only using at home was associated with greater odds of SAM use. For those 21+, using at a friend's house and outdoors were associated with increased odds of use; using at a bar/club was associated with lower odds. Using alone was associated with lower odds of use for those 21+. Engagement in risky activities (pre-gaming and drinking games) was not associated with SAM use., Discussion and Conclusions: SAM days are linked with use in private settings and social situations. Despite experiencing more harms on SAM days, SAM use is not more likely than alcohol use alone to occur in certain environments and situations traditionally found to be linked with increased risk. Findings may provide key insight for developing context-informed interventions focused on SAM use., (© 2020 Australasian Professional Society on Alcohol and other Drugs.)

Aims: To evaluate the prevalence of electrocardiogram (ECG) abnormalities in marijuana users as an indirect measure of subclinical cardiovascular disease (CVD)., Design: Longitudinal and cross-sectional secondary data analysis from the CARDIA (Coronary Artery Risk Development in Young Adults) study., Setting: Four communities in the United States., Participants: A total of 2585 participants from the 5115 black and white men and women recruited at age 18-30 years in 1985 to 1986 in CARDIA., Measurements: ECG abnormalities coded as minor and major abnormalities with the Minnesota code of electrocardiographic findings at year 20. Self-reported current (past 30 days) and computed cumulative life-time marijuana use (one 'marijuana-year' corresponds to 365 days of use) through assessments every 2-5 years. We fitted logistic regression models adjusting for sex, race, center, education, age, tobacco smoking, physical activity, alcohol use and body mass index., Findings: Among the 2585 participants with an ECG at year 20, mean age was 46, 57% were women, 45% were black; 83% had past exposure to marijuana and 11% were using marijuana currently. One hundred and seventy-three participants (7%) had major abnormalities and 944 (37%) had minor abnormalities. Comparing current with never use in multivariable-adjusted models, the odds ratio (OR) for major ECG abnormalities was 0.60 [95% confidence interval (CI) = 0.32-1.15] and for minor ECG abnormalities 1.21 (95% CI = 0.87-1.68). Results did not change after stratifying by sex and race. Cumulative marijuana use was not associated with ECG abnormalities., Conclusion: In a middle-aged US population, life-time cumulative and occasional current marijuana use were not associated with increases in electrocardiogram abnormalities. This adds to the growing body of evidence that occasional marijuana use and cardiovascular disease events and markers of subclinical atherosclerosis are not associated., (© 2020 Society for the Study of Addiction.)

Aims: To identify prototypical developmental patterns of tobacco product and cannabis use and co-use initiation during adolescence, and determine risk factors for and consequences of these initiation patterns., Design: Prospective repeated-measures cohort with eight semi-annual assessments during high school. Multiple-event process survival mixture modeling identified latent initiation classes with distinct patterns of variation in timing of use initiation of tobacco products and cannabis. We then estimated: (1) associations of baseline risk factors with membership in initiation classes and (2) differences between initiation classes in frequency of cannabis and tobacco product use at the final assessment., Setting: Ten high schools in the Los Angeles, CA, USA metropolitan area, 2013-17., Participants: Students [1031 (45.4%) males; mean (standard deviation) age at baseline = 14.6 (0.39) years] who had never used any tobacco products or cannabis at baseline 9th grade assessment (n = 2272)., Measurements: Self-report measures of electronic cigarette (e-cigarette), combustible cigarette, hookah, cigar/cigarillos and cannabis use were collected at each assessment., Findings: Four distinct tobacco and cannabis use initiation classes were identified: (1) early and high-risk cannabis and polytobacco initiators (n = 116; 5.1%); (2) early cannabis and polytobacco initiators (n = 172; 7.6%); (3) late cannabis and e-cigarette initiators (n = 431; 19.0%); and (4) abstainers (n = 1553; 68.4%). At baseline, older age for the early and high-risk cannabis and polytobacco initiators [odds ratio (OR) = 1.22, 95% confidence interval (CI) = 1.10, 1.35, P < 0.001], peer cannabis use (OR = 1.60, 95% CI = 1.23, 2.08, P < 0.001) and delinquent behavior (OR = 1.30, 95% CI = 1.08, 1.55, P = 0.004) were associated with membership in the three initiation classes (versus abstainers). Membership in the early and high-risk cannabis and polytobacco initiators class (versus three other classes) was significantly associated with increased past 30-day frequency and daily intensity of use at the final assessment (P-values < 0.001)., Conclusions: Older age, peer cannabis use and delinquent behavior appear to be risk factors for the initiation of tobacco/cannabis product use among high school students in the Los Angeles metropolitan region. Early and higher-risk polyproduct use initiation appears to be associated with greater escalation of past 30-day and daily tobacco and cannabis use at the end of the high school., (© 2020 Society for the Study of Addiction.)

Aims: To examine changes from 2017 to 2018 in e-cigarette use and ever marijuana use with e-cigarettes among US adolescents., Design: Analysis of data from the 2017 and 2018 National Youth Tobacco Survey (NYTS), cross-sectional surveys of US middle school (grades 6-8) and high school (grades 9-12) students., Setting: United States., Participants: US adolescent population from middle school, with mean age = 12.7 [standard deviation (SD) = 1.0] years, and high school, with mean age = 16.1 (SD = 1.3) years., Measurements: Analysis of e-cigarette use and ever use of marijuana with e-cigarettes according to frequency of use and smoking status, comparing 2017 with 2018. Frequent smoking and e-cigarette use was defined as use for ≥ 20 of the past 30 days., Findings: Past 30 days e-cigarette use was reported by 33.1% [95% confidence interval (CI) = 29.1-37.4%] of ever/no past 30 days smokers, 68.6% (95% CI = 64.1-72.7%) of past 30 days smokers and 7.2% (95% CI = 6.3-8.2%) of never smokers in 2018 and by 19.3% (95% CI = 16.1-23.1%), 53.0% (95% CI = 46.9-58.9%) and 3.3% (95% CI = 2.7-4.4%) in 2017, respectively (all P < 0.001). Prevalence of past 30 days e-cigarette use was higher among frequent smokers (69.8%, 95% CI = 62.3-76.5% in 2018; 53.8%, 95% CI = 44.1-63.2% in 2017, P < 0.001) and lower among never smokers. Most of the latter were infrequent users, while frequent and daily e-cigarette use was 18- and 24-fold lower compared with ever smokers, respectively. Approximately half of past 30 days and 70% of frequent e-cigarette users reported ever marijuana use with e-cigarettes in both years. Past 30 days smokers were more likely to report past 30 days e-cigarette use [odds ratio (OR) = 15.79, 95% CI = 12.58-19.83 in 2018; OR = 16.11, 95% CI = 12.44-20.86 in 2017) compared with adolescents reporting no past 30 days smoking., Conclusions: Among US adolescents, e-cigarette use increased in all smoking groups in 2018 compared with 2017. Frequent and daily e-cigarette use was far lower in never-smokers compared with ever-smokers. High prevalence of ever marijuana use with e-cigarettes was observed., (© 2020 Society for the Study of Addiction.)

Introduction and Aims: Adolescent drinking and cannabis use in Norway declined in the 2000s, and we tested the assumption that psychosocial problems were more strongly related to substance use when the prevalence was quite low (2012/2013) than when it was considerably higher (2002)., Design and Methods: Data stemmed from school surveys of almost 20 000 students aged 14-17 years in 2002 and 2012/2013 in the four largest cities in Norway. We assessed how various deviant behaviours and depressive mood were related to past-year measures on any alcohol intoxication, frequent intoxication (6+ times) and any cannabis use, and tested whether the associations varied significantly by survey year., Results: The prevalence of any intoxication episodes dropped markedly from 2002 (50%) to 2012/2013 (28%), as did the prevalence of frequent intoxication (29% vs. 10%) and any cannabis use (15% vs. 7%). Deviant behaviours and depressive mood were either more closely related to the drinking outcomes in 2012/2013 than in 2002, or the associations showed no temporal change. None of the associations with cannabis use varied significantly by survey year., Discussion and Conclusion: The assumption that psychosocial problems correlated more strongly with alcohol and cannabis use in a low-prevalence period (2012/2013) as compared to a high-prevalence period (2002) was partly supported, but only with respect to drinking. The strength of the associations with cannabis use was stable, which may reflect that the proportion reporting any use of the drug was low even in the relatively 'high-prevalence' period., (© 2020 The Authors. Drug and Alcohol Review published by John Wiley & Sons Australia, Ltd on behalf of Australasian Professional Society on Alcohol and other Drugs.)

Background and Aims: Uruguay and Chile have the highest levels of marijuana use in Latin America, and have experienced consistent increases during the last two decades. We aim to calculate separate age-period-cohort (APC) effects for past-year marijuana use in Uruguay and Chile, which have similar epidemiologica, and demographic profiles but diverging paths in cannabis regulation., Design: APC study in which period and cohort effects were estimated as first derivative deviations from their linear age trend, separately by country and gender., Setting: Uruguay and Chile., Participants: General population between 15 and 64 years., Measurements: Past-year marijuana use from household surveys with five repeated cross-sections between 2001 and 2018 in Uruguay (median n = 4616) and 13 between 1994 and 2018 in Chile (median n = 15 895)., Findings: Marijuana use prevalence in both countries peaked at 20-24 years of age and increased consistently across calendar years. Period effects were strong and positive, indicating that increases in use were evident across age groups. Relative to 2006 (reference year), Chilean period effects were approximately 48% lower in 1994 and approximately four times higher in 2018; in Uruguay, these effects were approximately 56% lower in 2001 and almost quadrupled in 2018. We observed non-linear cohort effects in Chile and similar patterns in Uruguay for the overall sample and women. In both countries, marijuana use increased for cohorts born between the mid-1970s and early 1990s, even in the context of rising period effects. Prevalence was consistently larger for men, but period increases were stronger in women., Conclusions: Age-period-cohort effects on past-year marijuana use appear to have been similar in Chile and Uruguay, decreasing with age and increasing over time at heterogeneous growth rates depending on gender and cohort. Current levels of marijuana use, including age and gender disparities, seem to be associated with recent common historical events in these two countries., (© 2020 Society for the Study of Addiction.)

Aims: We aimed to determine the association between stressful life events (SLEs) in the year prior to childbirth with (1) pre-pregnancy cannabis use, (2) cessation of cannabis use during pregnancy and (3) postpartum relapse to cannabis use., Design: We used data from the Pregnancy Risk Assessment Monitoring System (PRAMS) 2016, a cross-sectional, population-based surveillance system., Setting: Mailed and telephone surveys conducted in five states-Alaska, Colorado, Maine, Michigan and Washington-in the United States., Participants: Women (n = 6061) who delivered a live infant within the last 6 months and had data on cannabis use., Measurements: Self-reported data included SLEs (yes/no response for 14 individual events in the 12 months prior to childbirth) and cannabis use [yes/no prior to pregnancy, during pregnancy, and at the time of the survey (approximately 2-6 months postpartum)]. The associations between SLEs and cannabis use (primary outcomes) were examined in logistic regression models adjusted for maternal demographics (e.g. age, race, education), geography (i.e. state of residence) and cigarette smoking., Findings: Pre-pregnancy, 16.4% (997/6061) of respondents endorsed using cannabis, with 36.4% (363/997) continuing cannabis use during pregnancy. Among the 63.6% (634/997) who did not report use during pregnancy, 23.2% (147/634) relapsed to cannabis use during the postpartum. Nine of the 14 possible SLEs were associated with increased odds of pre-pregnancy cannabis use [e.g. husband/partner or mother went to jail, adjusted odds ratio (aOR) = 2.16, 95% confidence interval (CI) = 1.30-3.62] and four were associated with increased odds of continued cannabis use during pregnancy (e.g. husband/partner lost job, aOR = 2.19, 95% CI = 1.21-3.96). The odds of postpartum relapse to cannabis were significantly associated with two SLEs (husband/partner said they did not want pregnancy, aOR = 2.86, CI = 1.10-7.72; husband/partner or mother went to jail, aOR = 0.37, 95% CI = 0.13-1.00)., Conclusions: Stressful life events during the year prior to childbirth appear to be linked to greater odds of women's cannabis use during the perinatal period, especially during pre-pregnancy., (© 2020 Society for the Study of Addiction.)

Background and Objectives: There is a well-established causal link between substance use and intimate partner violence (IPV) perpetration and victimization. However, little is known about the complex emerging relationship between cannabis use and IPV. Because cannabis is the most commonly used drug in the United States and is associated with numerous IPV risk factors such as alcohol use, it is important to examine this relationship in greater detail., Method: The current exploratory study examined the association between (a) self-reported cannabis use during the past 90 days and (b) Δ9-tetrahydrocannabinol (THC) urine drug screens and IPV perpetration and victimization in a sample of 30 alcohol or drug-misusing community couples (N = 60 individual participants)., Results: The majority of participants (n = 50 individuals, 83.3%) had concordant cannabis self-reported and urine drug screen results. After accounting for demographic variables and quantity and frequency of alcohol and stimulant use, greater quantity and frequency of cannabis use as well as positive THC urine drug screen results were associated with greater physical IPV victimization, and greater quantity and frequency of cannabis were associated with greater IPV psychological victimization and perpetration, and physical IPV victimization. CONCLUSION AND SCIENTIFIC SIGNIFICANCE: Findings emphasize the unique and important role that cannabis plays in the occurrence of IPV among intact couples. Findings also underscore the feasibility and utility of integrating confirmatory biological samples into future studies on this topic in order to advance the science in this area. (Am J Addict 2020;00:00-00)., (© 2020 American Academy of Addiction Psychiatry.)

Background and Aims: Young adult college students in the United States are likely to be affected by marijuana liberalization trends. However, changes in students' marijuana use following recreational marijuana legalization (RML) have not been examined in more than one RML state at a time, or beyond 1-2 years post-legalization., Design: Cross-sectional National College Health Assessment survey administered twice yearly from 2008 to 2018., Setting: A total of 587 4-year colleges and universities in 48 US states., Participants: Undergraduates aged 18-26 years attending college in US states that did (n = 234 669 in seven states) or did not (n = 599 605 in 41 states) enact RML between 2008 and 2018., Measurements: Self-reported marijuana use (past 30 days) and individual and contextual covariates, institution-provided institutional and community covariates and publicly available dates when states enacted RML., Findings: Adjusting for covariates, state differences and state-specific linear time trends (accounting for pre-RML trends), prevalence of 30-day marijuana use increased more among students exposed to RML [odds ratio (OR) = 1.23, 95% confidence interval (CI) = 1.19-1.28, P < 0.001] than among non-RML state students throughout the same time-period; the results were similar for frequent use (≥ 20 days) (OR = 1.18, 95% CI = 1.10-1.27, P < 0.001). Interaction models supported stronger RML effects among students who were female, residing off-campus and aged 21 years and older; sexual orientation did not moderate RML effects. In the earliest states to enact RML (2012) there were increases in use prevalence in the second through the sixth year post-RML compared to pre-RML. In the second legalization group (2015) there were increases in the first and second year post-RML, and greater increases in the third year. In the later states (2016-17), increases were observed in both years after RML., Conclusions: In US states that enacted recreational marijuana legislation from 2012 to 2017 there was evidence for a general trend towards greater increases in marijuana use by college students and differential impact by gender, legal using age and campus residence., (© 2019 Society for the Study of Addiction.)

Background and Aims: The associations between traumatic events, substance use and perceived discrimination have been rarely studied among migrants in host countries. We examined whether pre-migration potentially traumatic experiences (PTEs) or perceived discrimination (PD) are associated with substance use among migrants with voluntary (Russians) and forced (Kurds) migration backgrounds., Design: Cross-sectional interview and health examination data from the Finnish Migrant Health and Wellbeing Study were used. The target sample (n = 1000 for each group) was drawn from the national population register using stratified random sampling by participants' country of birth and native language., Setting: Population-based data were collected from six cities in Finland during 2010-12., Participants: The participation rates were 68% (Russians) and 59% (Kurds). The analytical sample size varied (Russians n = 442-687, Kurds n = 459-613), as some participants completed only interview, health examination or short interview. The majority of Kurds had a refugee background (75%) while Russians had mainly migrated for other reasons (99%)., Measurements: The three main outcomes were self-reported binge drinking, daily smoking and life-time cannabis use. PTEs and PD were self-reported in the interview. Socio-demographic background, migration-related factors and current affective symptoms were adjusted for., Findings: Among Kurds, PTEs were associated with binge drinking [adjusted odds ratio (aOR) = 2.65, 95% confidence interval (CI) = 1.30-5.42] and PD was associated with life-time cannabis use (aOR = 3.89, 95% CI = 1.38-10.97) after adjusting for contextual factors. Among Russians, PTEs were associated with life-time cannabis use adjusting for contextual factors (aOR = 2.17, 95% CI = 1.12-4.18)., Conclusions: In Finland, pre-migration traumatic experiences appear to be associated with life-time cannabis use among the Russian migrant population (voluntary migration) and binge drinking among the Kurdish migrant population (forced migration). Perceived discrimination in Finland appears to be associated with life-time cannabis use among Kurdish migrants., (© 2019 Society for the Study of Addiction.)

Background: Prior research shows that negative drinking outcomes among young adults may be exacerbated by cannabis use. However, to date, there have been few longitudinal studies of associations between cannabis use and negative alcohol-related consequences. This study examined longitudinal within-person associations between cannabis use and several domains of negative alcohol consequences among young adults and explored the moderating role of sex., Method: We analyzed data from N = 997 students assessed 4 times per year over the first 3 years of university. At each time point, participants completed measures of past-month cannabis use frequency, typical weekly number of drinks, and 8 domains of negative alcohol consequences. Longitudinal associations were examined in multilevel models., Results: Within-person changes in frequency of cannabis use were not uniquely associated with changes in total alcohol consequences aggregated across several alcohol consequence domains. However, when examining alcohol consequence domains separately, within-person increases in cannabis use frequency were specifically associated with increases in some (but not all) of the more severe types of alcohol consequences, including risky behaviors, poor self-care, and alcohol dependence symptoms. No support was observed for the moderating role of sex in the longitudinal within-person associations between cannabis use and alcohol consequence domains., Conclusions: Findings suggest that within-person changes in cannabis use frequency among young adults are associated with corresponding changes in some domains of alcohol consequences (but not others) when examined over the course of several years. Results may inform targeted harm reduction interventions for young adult drinkers who use cannabis, although future research is needed to clarify the mechanisms of the observed associations., (© 2020 by the Research Society on Alcoholism.)

We examined whether pre-existing parent psychological distress moderated juvenile offenders' substance use, sexual risk, and mental health outcomes in a randomized trial. Forty-seven parent-adolescent dyads received either Family-based Affect Management Intervention (FAMI) for adolescent substance use and HIV prevention or adolescent-only Health Promotion Intervention (HPI). Parents' self-reported distress at baseline significantly moderated adolescents' self-reported marijuana use and alcohol use but not other outcomes at 3 months postintervention, producing crossover interactions. FAMI outperformed HPI when parents reported high-level distress, whereas HPI outperformed FAMI when parents reported low-level distress. This finding that the relative efficacy of interventions depends on the severity of parent psychological distress could inform efforts to match substance-using, justice-involved adolescents with the intervention most likely to benefit them., (© 2019 Society for Research on Adolescence.)

Background: Alcohol and marijuana are psychoactive substances commonly used by young adults and are independently associated with numerous acute and long-term consequences. Many young adults engage in simultaneous alcohol and marijuana (SAM) use to cross-fade (i.e., to enhance the effects of intoxication), although the extent to which alcohol use and alcohol-related consequences increase on SAM occasions compared to alcohol-only occasions is unclear. This study examines daily data among a sample of SAM users comparing SAM days to other days when young adults only used alcohol., Methods: A sample of 409 young adults (age 18 to 25; M age  = 21.6, SD = 2.2; 50.9% women) who reported SAM use in the past month completed 2 bursts of 14 days of daily surveys (28 days in total) assessing alcohol use, alcohol-related consequences, and SAM use., Results: Multilevel models based on alcohol-only and SAM days (n = 3,016 days; 391 individuals) indicated young adults drank more alcohol on SAM days compared to alcohol-only days (with no marijuana use). Similarly, days with SAM use were associated with more alcohol-related positive and negative consequences. The daily association between SAM use and positive consequences was statistically significant, after accounting for the amount of alcohol consumed; in contrast, the association between SAM use and negative consequences was diminished and nonsignificant., Conclusions: Among young adult SAM users, days with SAM use were associated with more alcohol use and positive consequences compared to days they only drank alcohol. Further examination of the motivational context for engaging in SAM use, as well as potential physiological interactions between alcohol and marijuana use on alcohol's effects, is warranted. Alcohol interventions might benefit from addressing increased alcohol use and alcohol-related consequences as risks associated with SAM use., (© 2020 by the Research Society on Alcoholism.)

Background and Aims: Little is known about how cannabis use over the life-course relates to harms in adulthood. The present study aimed to identify trajectories of cannabis use from adolescence to adulthood and examine both the predictors of these trajectories and adverse adult outcomes associated with those trajectories., Design: A latent trajectory analysis of a longitudinal birth cohort (from birth to age 35 years)., Setting and Participants: General community sample (n = 1065) from New Zealand., Measurement: Annual frequency of cannabis use (ages 15-35 years); childhood family and individual characteristics (birth to age 16 years); measures of adult outcomes (substance use disorders, ages 30-35 years; mental health disorders, ages 30-35 years; socio-economic outcomes at age 35 years; social/family outcomes at age 35 years)., Findings: A six-class solution was the best fit to the data. Individuals assigned to trajectories with higher levels of cannabis use were more likely to have experienced adverse childhood family and individual circumstances. Membership of trajectories with higher levels of use was associated with increased risk of adverse outcomes at ages 30-35 years. Adjustment of these associations for the childhood family and individual predictors largely did not reduce the magnitude of the associations., Conclusions: In New Zealand, long-term frequent cannabis use, or transition to such use, appears to be robustly associated with diverse harms in adulthood., (© 2019 Society for the Study of Addiction.)

Objective: Cannabis is an acknowledged risk factor for some mental disorders, but for others the evidence is inconclusive. Prescribed medicinal drugs can be used as proxies for mental disorders. In this study, we investigate how use of cannabis is prospectively related to prescription of antipsychotics, mood stabilizers, antidepressants, and anxiolytics., Methods: Data on cannabis exposure and relevant confounders were obtained from 2,602 individuals in the longitudinal Young in Norway Study, providing survey data from four data collection waves between 1992 and 2006. Data were coupled with information about prescriptions for psychotropic drugs from the Norwegian Prescription Database between 2007 and 2015., Results: Past year cannabis use increased the risk of prescription of antipsychotics (OR = 5.56, 95 % CI 1.64 - 18.87), mood stabilizers (OR = 5.36, 95 % CI 1.99 - 14.44) and antidepressants (OR = 2.10, 95 % CI 1.36 - 3.25), after accounting for sociodemographic variables, conduct problems, additional drug use, mental distress, and prescriptions the year before cannabis use was measured., Conclusions: In this study of young adults from the general population, past year cannabis use was associated with later prescriptions of antipsychotics, mood stabilizers, and antidepressants., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background and Objectives: Identical latent classes of substance use for 7 to 8 grade and 9 to 12 grade American Indian (AI) youth living on or near reservations suggest that patterns of substance use are established early among these youth. This study examines relationships of substance-related factors to latent class membership and whether these relationships differ by grade group., Methods: In-school surveys were administered to 1503 7 to 8 grade and 1995 9 to 12 grade students from 46 schools on or near reservations during the 2009/2010 to 2012/2013 school years. Four-class latent class models of substance use were specified and five classes of substance-related factors (peers, substance availability, perceived harm, family, early initiation), plus grade level and gender, were evaluated as predictors., Results: For 7 to 8 grade students, substance-related factors differentiated nonusers from users, while for 9 to 12 graders, these factors also differentiated types of users. Early initiation and peer factors were strongly related to class membership, while other factors were less strongly related., Discussion and Conclusions: Early initiation of alcohol or marijuana is strongly related to being in a substance-using class for AI youth. Because these youth tend to initiate use earlier that other US youth, prevention resources should be targeted to reaching them and their families before age 12., Scientific Significance: Predictors of latent classes of substance use were identified for reservation-based AI youth. While the classes were identical for 7 to 8 grade and 9 to 12 grade youth, predictors varied across grade group, which may inform how best to develop prevention efforts unique to middle and high school AI youth., (© 2019 American Academy of Addiction Psychiatry.)

Background: With expanding recreational cannabis legalisation, pregnant women and their offspring are at risk of potentially harmful consequences., Objectives: To assess the prevalence of recreational cannabis use among pregnant women, health outcomes associated with prenatal recreational cannabis use, and the potential impact of recreational cannabis legalisation on this population., Search Strategy: Five databases and the grey literature were systematically searched (2000-2019)., Selection Criteria: Human studies published in English or French reporting on the prevalence of prenatal recreational cannabis use in high-income countries., Data Collection and Analysis: Data on study characteristics, prenatal substance use, and health outcomes were extracted and qualitatively synthesised., Main Results: Forty-one publications met our inclusion criteria. The overall prevalence of prenatal cannabis use varied substantially (min-max: 0.24-22.6%), with the greatest use in the first trimester. In the three studies with temporal data available, rates of prenatal cannabis use increased across years. Only 7/41 and 5/41 studies provided information on gestational age of exposure and frequency of use, respectively. The concomitant use of alcohol, illicit drugs, and tobacco was higher among cannabis users than nonusers. Prenatal cannabis use was associated with select neonatal, but not maternal, health outcomes. There were insufficient data to compare prenatal cannabis use between the pre- and post-legalisation periods., Conclusion: Cannabis use among pregnant women is prevalent and may be associated with adverse neonatal outcomes. Future studies should assess the gestational age and frequency of cannabis exposure, and usage patterns prior to and following legalisation., Tweetable Abstract: Women who consume cannabis during pregnancy could risk predisposing their newborns to poor birth outcomes., (© 2019 Royal College of Obstetricians and Gynaecologists.)

Background and Aims: Alcohol use and marijuana use tend to be social activities among adolescents. Some youth use alcohol or marijuana while alone. This article provides a framework for examining the risk factors for and consequences of solitary alcohol and marijuana use, grounded in a motivational model that emphasizes coping with negative emotions, and provides the first systematic review of research on solitary alcohol and marijuana use among middle school- and high school-aged adolescents in the United States., Methods: PubMed, PsycINFO and Web of Science were searched. Articles were included if they mention solitary alcohol or marijuana (or illicit drug) use among adolescents aged 12-18 years. Studies on non-human animals, college students, non-English language publications and articles exclusively about solitary tobacco or inhalant use were excluded. Overall, 22 articles were selected., Results: Prevalence of adolescent solitary alcohol and marijuana use was relatively high (e.g. 14% life-time solitary drinking in the general adolescent population), particularly in high-risk subgroups (e.g. 38.8% life-time solitary drinking in a sample of youth recruited from clinical and community settings). Risk factors for solitary alcohol and marijuana use include earlier onset and heavier use, coping motives, negative emotions and positive expectancies about use. Solitary alcohol and marijuana use are prospectively associated with later substance use disorder (SUD) symptoms, diminished academic performance and perceived health., Conclusions: Approximately 1 in 7 adolescents in the US appear to have engaged in solitary alcohol and marijuana use at some point. It is positively associated with extent of drinking and marijuana use, cop;ing motives, negative emotions, and positive expectancies, as well as subsequent SUD symptoms and poor academic and health-related outcomes., (© 2019 Society for the Study of Addiction.)

Background and Objectives: Among newly incident cannabis users, fewer than 4% develop cannabis dependence syndromes within 12 to 24 months, but earlier cannabis side effect (SE) incidence and early syndrome formation remains understudied. We estimate cannabis SE incidence within ~1 to 90 days after first use, and estimate odds ratios (OR) for SE pairs to quantify potential syndromic "running together.", Methods: Each year, 2004 to 2014, the US populations under study consisted of noninstitutionalized civilian residents age 12-years-and-older, sampled for National Surveys on Drug Use and Health. Computerized self-interviews identified 3710 newly incident cannabis users and asked about SEs. Analysis-weighted year-specific SE and SE-SE pair incidence proportions were estimated. Analysis-weighted odds ratio (OR) estimates quantify SE-SE co-occurrences, judged as "greater than chance" when lower bounds (LB) of 95% confidence intervals (CIs) exceed 1.0. Meta-analysis is used to summarize and to check reproducibility., Results: Illustrative of estimates on 17 SEs, roughly 1/2 of cannabis initiates experienced "wanting or trying to cut down or stop using," but 80% of these cut back, such that less than 7% had symptom-like inability to cut back or stop. An estimated 25% had "spent a lot of time getting or using cannabis." The SE-SE paired estimate is 2.8% for those who had spent a lot of time and also had wanted/tried to cut down (95% CI = 2.0, 4.0). OR estimation suggests no syndromic co-occurrence of this SE-SE pair (OR = 0.9; 95% CI = 0.5, 1.6). In contrast, "cannabis causing serious problems at home/work/school" and "continuing to use despite physical problems" were more rare, but had strong SE-SE co-occurrence (OR = 14.8, LB = 2.4). For 78 of 136 possible SE-SE pairs, meta-analysis LB estimates exceeded the 1.0 threshold., Conclusion and Scientific Significance: In these US community samples of cannabis initiates studied soon after first use, the vast majority were free of individual SE experiences counted toward Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition cannabis use disorder diagnoses. For a minority, SE-SE pairs might indicate syndrome formation. These epidemiological meta-analysis estimates might find use in refinement of clinical practice guidelines for fast effective syndrome screens when primary care patients are seen soon after cannabis onset, akin to clinical screening guides designed for newly incident drinkers (Am J Addict 2019;00:1-9)., (© 2019 American Academy of Addiction Psychiatry.)

Background and Aims: As the legal status of cannabis changes across the United States and modes of administration expand, it is important to examine the potential impact on adolescent cannabis use. This study aimed to assess changes in prevalence of frequent cannabis use in adolescents in the United States and how far this varies by age and cohort., Design: Analysis of Monitoring the Future, a nationally representative annual survey of 8th-, 10th- and 12th-grade students in the United States conducted from 1991 to 2018., Setting: In-school surveys completed by US adolescents., Participants: A total of 1 236 159 8th-, 10th- and 12th-graders; 51.5% female, 59.6% non-Hispanic white, 12.3% non-Hispanic black, 13.4% Hispanic and 14.7% other race/ethnicity., Measurements: Frequent cannabis use (FCU), defined as six or more occasions in the past 30 days, stratified by sex, race/ethnicity and parental education., Findings: FCU among US adolescents increased over the study period; the peak in 2010-18 was 11.4% among 18-year-old students. This increase was best explained by both period and cohort effects. Compared with respondents in 2005, adolescents surveyed in 2018 had period effects in FCU that were 1.6 times greater. Adolescents in younger birth cohorts (those born > 1988) had a lower increase in FCU than those born prior to 1988. Results were consistent across sex, parent education and race/ethnicity, with period effects indicating increasing FCU after 2005 and cohort effects indicating a lower magnitude of increase in more recent birth cohorts. Age and parental education disparities in FCU have increased over time, whereas race/ethnicity differences have converged over time; black students were 0.67 [95% confidence interval (CI) = 0.64-0.70] times as likely to use cannabis frequently as white students from 1991 to 2000, and 1.03 (95% CI = 0.98-1.09) times as likely from 2011 to 2018 (P-value for time interaction < 0.001)., Conclusions: The prevalence of frequent cannabis use (FCU) increased from 1991 to 2018 among older adolescents in the United States. Racial/ethnic differences in FCU converged, whereas parental education differences have diverged., (© 2019 Society for the Study of Addiction.)

Background and Aims: Alcohol-induced blackout (AIB) is a common alcohol-related adverse event occurring during teenage years. Although research provides evidence that AIB predicts acute negative consequences, less is known about the associations of AIB with chronic consequences, such as alcohol dependence (AD). This study estimated the associations between an experience of AIB at age 20 and the incidence, maintenance and severity of AD at age 25 among Swiss men., Design: Prospective cohort study with 5.5 years separating baseline and follow-up., Setting: Switzerland., Participants: Swiss male drinkers (n = 5469, age 20 at baseline) drawn from the Cohort Study on Substance Use Risk Factors (C-SURF)., Measurements: Self-report questionnaires assessing AIB, AD, alcohol (drinking volume, binge drinking), cigarette and cannabis use, several risk factors (sensation-seeking, family history of problematic alcohol use, age of first alcohol intoxication) and socio-demographic variables., Findings: Generalized estimating equation models with and without adjustment for risk factors, including alcohol use and socio-demographics, showed that AIB at age 20 significantly predicted the incidence of AD at age 25 in men without AD at age 20 [odds ratio (OR) = 2.52, 95% confidence interval (CI), unadjusted = 2.04, 3.11, P < 0.001; fully adjusted, OR = 1.47, 95% CI = 1.13, 1.91, P = 0.004], maintenance of AD in men with AD at age 20 (unadjusted, OR = 1.82, 95% CI = 1.12, 2.95, P = 0.015; fully adjusted, OR = 1.66, 95% CI = 1.00, 2.76, P = 0.048] and AD severity [unadjusted incidence rate ratio (IRR) = 1.89, 95% CI = 1.69, 2.11, P < 0.001; fully adjusted, IRR = 1.20, 95% CI = 1.10, 1.31, P < 0.001]., Conclusions: Among Swiss men, alcohol-induced blackout at age 20 predicts the development, maintenance and severity of alcohol dependence at age 25., (© 2019 Society for the Study of Addiction.)

Aims: To perform a wastewater-based analysis to explore the impact of newly legalized retail cannabis sales on its use and to determine if this approach could estimate the size of the legal market place, which began 1 August 2014 in the study area., Design: Laboratory study of raw wastewater samples collected and analyzed over the 3-year period from 2014 to 2016., Setting and Participants: Samples obtained from the two wastewater treatment plants that serviced a municipality of 200 000 people in the state of Washington, USA., Measurements: Quantitative analysis of 24-hour composite influent samples for the metabolite of the active ingredient in cannabis, 11-nor-9-Carboxy-Δ9-tetrahydrocannabinol (THC-COOH) were performed by liquid chromatography coupled to mass spectrometry., Findings: Wastewater estimates for THC-COOH increased by 9% per quarter, suggesting a doubling in cannabis consumption from 1 December 2013 to 31 December 2016. State-sold THC increased at nearly 70% per quarter, while stores operated from 1 August 2014 to 31 December 2016. Estimating the proportion of the total cannabis market supplied by state-regulated cannabis from these data is not currently achievable., Conclusion: A wastewater-based measure of cannabis consumption suggests a significant increase in consumption in Washington, USA following legalization, and that legal sales appear to have displaced a large portion of the illicit market., (© 2019 Society for the Study of Addiction.)

Aim: Duration of untreated psychosis (DUP), or the time between onset of psychosis and treatment initiation, is a prognostic factor of schizophrenia. However, few studies evaluated the relative influence of individual-related factors on this duration. The objective of this study was to evaluate the influence of socio-demographic, clinical and cannabis use on DUP., Methods: This study was part of a large prospective study in help-seeking individuals referred to our specialized early detection / intervention clinic in the Service Hospitalo-Universitaire of Sainte-Anne Hospital in Paris (ICAAR study). We explored 33 consecutive patients who crossed the CAARMS' threshold of psychosis. The DUP and cannabis consumption history were explored during the baseline comprehensive assessment using all available sources (direct interviews of patients, parents, practitioners). Correlations between socio-demographic, clinical and cannabis use, and DUP were studied. A multiple linear regression model was used to determine the variables that could significantly predict DUP., Results: When considered individually, none of the socio-demographic and disease characteristic factors was associated with DUP, with the exception of level of education. In the multivariate analysis, age at inclusion, negative symptoms and history of cannabis use significantly influenced DUP., Conclusion: The determinants of DUP are multi-factorial and include individual centred factors, such as age, cannabis and negative symptoms. The identification of factors resulting in delayed access to care may promote the development of effective strategies to reduce DUP in early psychosis and target effective early intervention., (© 2018 John Wiley & Sons Australia, Ltd.)

Background and Objective: US college student marijuana use is the highest since 1980. The objective was to investigate use characteristics among college students., Methods: The RADARS® System College Survey Program surveyed individuals in a university, technical or online school. This was a secondary analysis of existing data., Results: Seven thousand one hundred five students were enrolled, <30% of students' perceived marijuana use a health risk. Students in medical states were more likely to use marijuana compared to non-legal states. (p < .001) Smoking and edibles were common methods of use., Conclusions: Higher reports of college student use were observed in medical states without differences in risk perception., Scientific Significance: This study further demonstrates the public health impact of marijuana legalization by comparing college study use of marijuana by state legalization status, and demonstrating high rates of use of concentrated products. These findings should be factored when determining regulations and preventative measures when legalizing marijuana. (Am J Addict 2019;28:266-269)., (© 2019 American Academy of Addiction Psychiatry.)

Background: Alcohol and marijuana users often engage in simultaneous alcohol and marijuana (SAM) use (i.e., using the 2 substances together so that their effects overlap), which can result in more negative consequences than using either substance alone. Nevertheless, little is known about SAM use among contemporary college students to aid in the development of preventive interventions. This study examined SAM use patterns, demographic correlates of SAM use, and normative influences on SAM use and related negative consequences among college students., Methods: Students who had used alcohol and marijuana in the past year were recruited from 3 state universities in states with different laws regarding recreational marijuana use (N = 1,389). They completed an online survey, which assessed their own alcohol, marijuana, and SAM use and related consequences, their perceptions of the proportion of same-gender peers and close friends who engaged in SAM use, marijuana access, and demographic characteristics., Results: About three-fourths of participants reported at least 1 occasion of SAM use in the past year with an average frequency of twice per month among SAM users. There were significant differences in SAM use prevalence and frequency by sociodemographic characteristics controlling for past-year alcohol and marijuana frequency. Students in a state with decriminalized recreational marijuana use reported higher frequency of past-year SAM use than students in states with legalized or criminalized use. There were significant demographic differences in perceived norms regarding SAM use among close friends and same-gender peers. SAM users endorsed significantly higher perceived peer and friend norms than nonusers. Also, higher perceived norms predicted more frequent SAM use and more negative consequences of use., Conclusions: Results indicate a need for prevention programs on college campuses that address SAM use. Interventions that use personalized normative feedback may be effective., (© 2019 by the Research Society on Alcoholism.)

Background and Aims: Long-term frequent marijuana use is associated with significant negative outcomes, yet little is known about the longitudinal course of marijuana use among those who start frequent use during adolescence. Objectives are (a) to identify latent patterns of within-person marijuana use from ages 19-30 years among 12th graders reporting frequent marijuana use, (b) to examine if membership in identified patterns has changed across historical time and (c) to examine if key covariates differentiate class membership., Design, Setting, Participants: Longitudinal, national US panel data from 4423 individuals [53.4% of the eligible sample; 2744 (62%) males] who reported frequent marijuana use in 12th grade (modal age 18 years; senior year cohorts 1976-2006) followed biennially from ages 19/20 to 29/30., Measurements: Self-reported past 30-day marijuana use (frequent use defined as use on 20+ occasions), demographics, college graduation, marriage and parenthood., Findings: Repeated-measures latent class analysis (RMLCA) identified five latent classes of past 30-day marijuana use from ages 19/20 to 29/30: continued frequent users (estimated membership 23.4%); frequent to non-frequent users (15.5%); consistent non-frequent users (18.4%); non-frequent users to discontinuers (19.5%); and discontinuers (23.2%). In multivariable models, membership in the highest-risk latent class (continued frequent users) versus one or more of the lower-risk latent classes was more likely for recent cohorts (P = 0.038 to <0.001), as well as those who did not marry (P = 0.039 to < 0.001) or become parents (P = 0.001) by modal age 29/30., Conclusions: Nearly one in four 12th grade (modal age 18 years) frequent marijuana users in the US continues to report high frequency use to age 30; the proportion continuing high frequency use across young adulthood has increased among more recent cohorts., (© 2019 Society for the Study of Addiction.)

Using data from a cohort study of students at risk for high school dropout, we examined associations between violence exposure and past 30-day alcohol and marijuana use. We used varying-coefficient regression with person-level fixed effects to estimate how those associations changed within-person across ages approximately 14-23. Generally, violence perpetration was most strongly associated with substance use, within-person. Substance use became increasingly associated with both observed violence and violence perpetration during early/middle adolescence; this increase continued longer into development (age 18+) for alcohol use. Across most of the age range studied here, violence victimization was minimally associated with within-person changes in substance use. Results indicate age-specific associations between violence exposure and alcohol and other drug use, which may be useful for informing prevention strategies., (© 2018 Society for Research on Adolescence.)

Aims: To determine whether cannabis use during adolescence can increase risk not only for cannabis use disorder (CUD) but also for conduct problems, potentially mediated by exposure to peers who use cannabis., Design, Setting, Participants: Longitudinal study analyzing four waves of longitudinal data from 364 racially and socio-economically diverse, urban, US community youth (at baseline: M age  = 13.51 (0.95); 49.1% female)., Measurements: Self-reports of cannabis use, conduct problems, proportion of peers using cannabis and CUD criteria at the final wave were analyzed using a method sensitive to changes over development, the random-intercept cross-lagged panel model., Findings: Change in cannabis use did not predict changes in conduct problems or peer cannabis use over time, controlling for gender, race-ethnicity and socio-economic status. Instead, increases in conduct problems predicted increases in cannabis use and ultimately CUD, with some of the effect mediated by increases in the prevalence of peer cannabis use [β = 0.12, 95% confidence interval (CI) = 0.07, 0.20]. Additionally, affiliation with peers who used cannabis predicted subsequent CUD via increased personal cannabis use (β = 0.08, 95% CI = 0.04, 0.14). Significant within-person betas for the cross-lagged effects ranged between 0.20 and 0.27., Conclusions: Cannabis use in adolescence does not appear to lead to greater conduct problems or association with cannabis-using peers apart from pre-existing conduct problems. Instead, adolescents who (1) increasingly affiliate with cannabis-using peers or (2) have increasing levels of conduct problems are more likely to use cannabis, and this cascading chain of events appears to predict cannabis use disorder in emerging adulthood., (© 2018 The Authors. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.)

Background and Aims: Few longitudinal studies have examined the relationship between food insecurity and substance use. We aimed to investigate this relationship using longitudinal data among women with or at risk for HIV in the United States., Design: Women's Interagency HIV Study (WIHS), a prospective cohort study., Setting: Nine sites across the United States., Participants: A total of 2553 women with or at risk for HIV., Measurements: Semi-annual structured interviews were conducted during April 2013-March 2016. Food security (FS) was the primary predictor, measured using the Household Food Security Survey Module. Outcomes were: any illicit substance use except cannabis; licit or illicit cannabis use; stimulant use (crack, cocaine, or methamphetamine); opioid use (heroin or methadone in a non-prescribed way); and prescription drug misuse (prescription narcotics, amphetamines, or tranquilizers in a non-prescribed way) since the last visit. We used multivariable logistic regression with random effects to examine longitudinal associations of current and previous FS with the outcomes simultaneously, adjusting for socio-demographic factors, HIV serostatus, physical health and health insurance., Findings: Average number of visits was 4.6. At baseline, 71% of participants were HIV-seropositive, 44% reported marginal, low, or very low FS, and 13% were using illicit substances. In adjusted analyses, current low and very low FS were significantly associated with 1.59 [95% confidence interval (CI) = 1.02, 2.46; P = 0.039] and 2.48 (95% CI = 1.52, 4.04; P < 0.001) higher odds of any illicit substance use, compared to high FS, and also with higher odds of cannabis, stimulant and opioid use, exhibiting a consistent dose-response relationship. Marginal, low, and very low FS at the previous visit were associated with 1.66 (95% CI = 1.08, 2.54; P = 0.020), 1.77 (95% CI = 1.14, 2.74; P = 0.011), and 2.28 (95% CI = 1.43, 3.64; P < 0.001) higher odds of current illicit substance use., Conclusions: Food insecurity appears to be longitudinally associated with substance use among US women with or at risk for HIV., (© 2018 Society for the Study of Addiction.)

Background: Postsecondary students in Western countries exhibit a high prevalence of cannabis and tobacco use disorders. The etiology of these problems is contributed by several psychosocial factors, including childhood adversity and trauma; however, the mechanisms whereby these environmental determinants predispose to the use of these substances remain elusive, due to our poor knowledge of genetic and biological moderators. Converging evidence points to the monoamine oxidase A (MAOA) gene as a moderator of the effects of lifetime stress on the initiation of substance use., Aims: Building on these premises, in this study, we analyzed whether MAOA upstream variable number tandem repeat (uVNTR) alleles interact with child maltreatment history to predict for lifetime cannabis and tobacco consumption., Materials and Methods: Five hundred college students (age: 18-25 years) from a large Midwestern University were surveyed for their child maltreatment history (encompassing emotional, physical, and sexual abuse, as well as emotional and physical neglect) and lifetime consumption of cannabis and tobacco. Saliva samples were obtained to determine the MAOA uVNTR genotype of each participant., Results: In female students, lifetime tobacco and cannabis use was predicted by the interaction of physical and emotional abuse with high-activity MAOA allelic variants; conversely, in males, the interaction of low-activity MAOA alleles and physical abuse was associated with lifetime use of tobacco, but not cannabis., Discussion: These findings collectively suggest that the vulnerability to smoke tobacco and cannabis is predicted by sex-dimorphic interactions of MAOA gene with childhood abuse., Conclusion: These biosocial underpinnings of tobacco and cannabis use may prove important in the development of novel personalized preventive strategies for substance use disorders in adolescents., (© 2018 John Wiley & Sons Ltd.)

Background and Aims: Cannabis use is common among people on opioid agonist treatment (OAT), causing concern for some care providers. However, there is limited and conflicting evidence on the impact of cannabis use on OAT outcomes. Given the critical role of retention in OAT in reducing opioid-related morbidity and mortality, we aimed to estimate the association of at least daily cannabis use on the likelihood of retention in treatment among people initiating OAT. As a secondary aim we tested the impacts of less frequent cannabis use., Design: Data were drawn from two community-recruited prospective cohorts of people who use illicit drugs (PWUD). Participants were followed for a median of 81 months (interquartile range = 37-130)., Setting: Vancouver, Canada., Participants: This study comprised a total of 820 PWUD (57.8% men, 59.4% of Caucasian ethnicity, 32.2% HIV-positive) initiating OAT between December 1996 and May 2016. The proportion of women was higher among HIV-negative participants, with no other significant differences., Measurements: The primary outcome was retention in OAT, defined as remaining in OAT (methadone or buprenorphine/naloxone-based) for two consecutive 6-month follow-up periods. The primary explanatory variable was cannabis use (at least daily versus less than daily) during the same 6-month period. Confounders assessed included: socio-demographic characteristics, substance use patterns and social-structural exposures., Findings: In adjusted analysis, at least daily cannabis use was positively associated with retention in OAT [adjusted odds ratio (aOR) = 1.21, 95% confidence interval (CI) = 1.04-1.41]. Our secondary analysis showed that compared with non-cannabis users, at least daily users had increased odds of retention in OAT (aOR = 1.20, 95% CI = 1.02-1.43), but not less than daily users (aOR = 1.00, 95% CI = 0.87-1.14)., Conclusions: Among people who use illicit drugs initiating opioid agonist treatment in Vancouver, at least daily cannabis use was associated with approximately 21% greater odds of retention in treatment compared with less than daily consumption., (© 2018 Society for the Study of Addiction.)