Daily Patterns of Marijuana and Alcohol Co-Use Among Individuals with Alcohol and Cannabis Use Disorders

Examining within-person associations between alcohol and cannabis use and hooking up among adolescents and young adults in the United States

OBJECTIVE

This study examined daily associations between alcohol use, cannabis use, and simultaneous alcohol and cannabis/marijuana (SAM) use with the likelihood of hooking up (uncommitted sexual encounter that may or may not include intercourse).

METHOD

We used a longitudinal measurement burst ecological momentary assessment (EMA) design with 3-week EMA bursts with daily measurements repeated quarterly across 12 months. 1,009 (57 % female, Mean age = 20.00 [SD = 3.21]) Texan adolescents and young adults ages 15-25 participated in the study. Mixed effects logistic regression models were estimated using maximum likelihood estimation to evaluate the associations between substance use and hooking up.

RESULTS

Within-person results indicated that participants were more likely to hook up on days with alcohol use and on days with cannabis use, but not on days with SAM use. Participants were also more likely to hook up on drinking days with higher-than-usual alcohol use. Between-person results indicated that participants who used alcohol more often or cannabis more often on average were more likely to hook up, and participants who tended to drink more on drinking days were more likely to hook up.

CONCLUSIONS

Given the significant daily-level associations between alcohol and cannabis use and hooking up behavior, public health initiatives should focus on developing interventions to reduce alcohol and cannabis use and promote safer hooking up behavior among adolescents and young adults.

Cross-substance Effects of Adolescent Exposure to Alcohol Content in Popular Movies on Cannabis Initiation

Objective

Alcohol is the most frequently depicted substance in the media, and adolescent exposure to alcohol in the media predicts alcohol use. There is relatively little research on exposure to cannabis in the media, but exposure to alcohol content may exert cross-substance effects on cannabis use. Given the social and health risks associated with early cannabis use, the present study aims to assess the cross-substance effects of exposure to alcohol media content on age of cannabis initiation.

Method

A sample of 830 middle school students (53% female) reported on movie alcohol exposure and cannabis initiation longitudinally until high school completion. Discrete-time survival models examined whether movie alcohol exposure predicted subsequent initiation among students who were cannabis-naïve at baseline, controlling for demographic, social, and behavioral covariates. The interaction between sex and movie alcohol exposure was also explored.

Results

One third (33%) of participants reported cannabis initiation with a mean of 5.57 estimated hours (SD = 4.29) of movie alcohol exposure. A 1-hour increase in movie exposure predicted a significant 16% increased probability of cannabis initiation in models adjusted for demographic variables and a significant 14% increase in models adjusted for demographic, behavioral, and social variables. No differences were observed across sex.

Conclusions

Greater adolescent exposure to alcohol content in the media was associated with earlier cannabis initiation above and beyond other etiologically relevant demographic, behavioral, and social variables. The influence of cross-substance media exposures warrants further exploration and should be taken into consideration in the development of preventive interventions for youth substance use.

Alcohol and cannabis use and co-use among Whites and Hispanics on and off the U.S./Mexico border in California

This paper examines self-reported rates of drinking and cannabis use and co-use among White and Hispanic adults randomly selected in four counties in California: Imperial on the border; and Kern, Tulare, and Madera in California's Central Valley. Co-use was significantly higher among the U.S. born than among those born abroad, and in the Central Valley than on the border. Co-users were heavier drinkers, had higher rates of alcohol use disorder, other alcohol problems, and a positive history of illicit drug use than drinkers only.

Prevalence and Correlates of Cannabis Use among U.S. Veterans during the Second Wave of the COVID-19 Pandemic

INTRODUCTION

Military veterans are at increased risk of substance use disorders. Limited research is available about veterans' cannabis use (CU) during the coronavirus disease 2019 (COVID-19) pandemic. This study estimated the prevalence of past 30-day CU, investigated individual-level correlates of past 30-day CU, and evaluated the reasons (medical, recreational, or both) of past 30-day CU among U.S. Veterans during the second wave of the COVID-19 pandemic.

MATERIALS AND METHODS

We used population-based, cross-sectional data from the 2021 Behavioral Risk Factor Surveillance System Survey Marijuana Use model. The sample included nationally representative military veterans aged 18+ years (n = 11,167). The outcome was past 30-day CU. Individual-level demographic, socioeconomic, behavioral, and clinical correlates were examined. Analyses were weighted to account for the survey's complex design with results generalizable to nearly 2.9 million veterans. We conducted weighted descriptive statistics, prevalence estimates, and multivariable logistic regression analyses.

RESULTS

Out of 2.9 million veterans, 11.1% self-reported as non-Hispanic Black, 3.7% Hispanic, and 79.1% non-Hispanic White; 88.5% were men, and 72.8% were aged 50+ years. About 14.6% were current tobacco smokers, 4.7% were current e-cigarette users, 12.5% were binge alcohol drinkers, and 43.4% had three or more comorbid conditions. Overall, 8.5% reported CU in the past 30 days, of which 30.4% used it for medical reasons and 25.8% used it for nonmedical reasons. The prevalence of past 30-day CU decreased with age, education, and income level. Compared to their counterparts, the odds of past 30-day CU were greater among men, those living in urban areas, those with frequent mental distress, infrequent physical distress, and those who had at least one comorbid condition. Non-Hispanic Black veterans had 89% increased odds of past 30-day CU (adjusted odds ratio [AOR] =1.89, 95% confidence interval [CI], 1.19-3.0) compared with non-Hispanic White veterans. Current tobacco smokers had 3.54 (95% CI, 2.40-5.24) and former smokers had 1.78 (95% CI, 1.28-2.47) times higher odds of reporting past 30-day CU than never smokers. Current e-cigarette use (AOR = 3.37, 95% CI, 2.20-5.16) and binge drinking (AOR = 3.18, 95% CI, 2.29-4.41) were also statistically significantly associated with increased odds of past 30-day CU compared to no e-cigarette use and no binge drinking.

CONCLUSIONS

CU is prevalent among veterans, and certain subgroups are at higher risk of CU. Thus, identifying high-risk subgroups of veterans and adequately educating them about CU's benefits, risks, and safety is crucial.

VC, Niez RA, Delos Santos FE, Magramo MM, Yap-Tan AR, Sy FAR, Kasimieh O. Predictors and Prevalence of Alcohol and Cannabis Co-use Among Filipino Adolescents: Evidence From a School-based Student Health Survey

OBJECTIVES

This study explored the prevalence and predictors of alcohol and cannabis co-use among 9263 Filipino adolescents, using data from the 2019 Global School-based Student Health Survey (GSHS).

METHODS

We conducted a cross-sectional secondary analysis of the GSHS, targeting adolescents aged 13-17 years and excluding cases with incomplete data on alcohol and cannabis use. Our analysis employed the bivariate chi-square test of independence and multivariable logistic regression using Stata version 18 to identify significant predictors of co-use, with a p-value threshold set at 0.05.

RESULTS

The weighted prevalence of co-users was 4.2% (95% confidence interval [CI], 3.4 to 5.3). Significant predictors included male sex (adjusted odds ratio [aOR], 4.50; 95% CI, 3.31 to 6.10; p<0.001) and being in a lower academic year, specifically grade 7 (aOR, 4.08; 95% CI, 2.39 to 6.99; p<0.001) and grade 8 (aOR, 2.20; 95% CI, 1.30 to 3.72; p=0.003). Poor sleep quality was also a significant predictor (aOR, 1.77; 95% CI, 1.29 to 2.44; p<0.001), as was a history of attempted suicide (aOR, 5.31; 95% CI, 4.00 to 7.06; p<0.001). Physical inactivity was associated with lower odds of co-use (aOR, 0.45; 95% CI, 0.33 to 0.62; p<0.001). Additionally, non-attendance of physical education classes (aOR, 1.48; 95% CI, 1.06 to 2.05; p=0.021), infrequent unapproved parental checks (aOR, 1.37; 95% CI, 1.04 to 1.80; p=0.024), and lower parental awareness of free-time activities (aOR, 0.63; 95% CI, 0.45 to 0.87; p=0.005) were associated with higher odds of co-use. Factors not significantly linked to co-use included age group, being in grade 9, always feeling lonely, having no close friends, being bullied outside school, and whether a parent or guardian understood the adolescent's worries.

CONCLUSIONS

The findings highlight the critical need for comprehensive interventions in the Philippines, addressing not only physical inactivity and parental monitoring but also focusing on sex, academic grade, participation in physical education classes, sleep quality, and suicide attempt history, to effectively reduce alcohol and cannabis co-use among adolescents.

Is there a relationship between abuse of alcohol and illicit drugs seen in hair results?

Combined use of alcohol and illicit drugs is a serious health and social problem. In this study, it was examined, whether a relationship between alcohol and drug abuse can be ascertained by comparison of alcohol marker and drug concentrations in hair. In the frame of a social support system for families with parental abuse of illicit drugs, hair samples were analyzed between 2011 and 2022 for methadone, heroin (6-acetylmorphine), cocaine, amphetamine, ecstasy (MDMA), cannabinoids (THC), and the alcohol markers ethyl glucuronide (EtG) and ethyl palmitate (EtPa). For 1314 hair samples from adolescent and adult family members, the hair results show a prevalence of combined occasional or regular drug use and social or abusive alcohol use of 41%-60% except heroin (35%). The drug concentrations were statistically compared in the three categories of abstinence or moderate drinking, social drinking, and alcohol abuse. For the most frequently detected drug cocaine (n = 703), a significant increase of the concentrations with rising alcohol consumption was found. The frequent detection of cocaethylene proved the preferred simultaneous intake of both substances. For THC (n = 489), no significant difference between the alcohol consumer groups was seen. Concerning the less frequently detected methadone (n = 89), 6-acetylmorphine (n = 92), amphetamine (n = 123), and MDMA (n = 105), no clear trend between drug and alcohol marker results was determined. It is concluded that the evaluation of hair results is an appropriate way to study the extent of combined drug-alcohol consumption and complements other studies based on acquisition of consumption data by interview or questionnaire.

Genetic influences and causal pathways shared between cannabis use disorder and other substance use traits

Cannabis use disorder (CanUD) has increased with the legalization of the use of cannabis. Around 20% of individuals using cannabis develop CanUD, and the number of users has grown with increasing ease of access. CanUD and other substance use disorders (SUDs) are associated phenotypically and genetically. We leveraged new CanUD genomics data to undertake genetically-informed analyses with unprecedented power, to investigate the genetic architecture and causal relationships between CanUD and lifetime cannabis use with risk for developing SUDs and substance use traits. Analyses included calculating local and global genetic correlations, genomic structural equation modeling (genomicSEM), and Mendelian Randomization (MR). Results from the genetic correlation and genomicSEM analyses demonstrated that CanUD and cannabis use differ in their relationships with SUDs and substance use traits. We found significant causal effects of CanUD influencing all the analyzed traits: opioid use disorder (OUD) (Inverse variant weighted, IVW β = 0.925 ± 0.082), problematic alcohol use (PAU) (IVW β = 0.443 ± 0.030), drinks per week (DPW) (IVW β = 0.182 ± 0.025), Fagerström Test for Nicotine Dependence (FTND) (IVW β = 0.183 ± 0.052), cigarettes per day (IVW β = 0.150 ± 0.045), current versus former smokers (IVW β = 0.178 ± 0.052), and smoking initiation (IVW β = 0.405 ± 0.042). We also found evidence of bidirectionality showing that OUD, PAU, smoking initiation, smoking cessation, and DPW all increase risk of developing CanUD. For cannabis use, bidirectional relationships were inferred with PAU, smoking initiation, and DPW; cannabis use was also associated with a higher risk of developing OUD (IVW β = 0.785 ± 0.266). GenomicSEM confirmed that CanUD and cannabis use load onto different genetic factors. We conclude that CanUD and cannabis use can increase the risk of developing other SUDs. This has substantial public health implications; the move towards legalization of cannabis use may be expected to increase other kinds of problematic substance use. These harmful outcomes are in addition to the medical harms associated directly with CanUD.

Latent Classes of Simultaneous Alcohol and Cannabis Use and Associations with Consequences using Daily Data

Objective

Simultaneous alcohol and cannabis use (i.e., marijuana, [SAM], using alcohol and cannabis so effects overlap) is associated with increased consumption and consequences compared to single-substance use. SAM use prevalence is increasing, yet there is heterogeneity in use patterns among those engaging in SAM use, which may lead to differential consequences.

Method

This study drew on daily data to characterize latent profiles of cannabis, alcohol, and SAM use patterns and to test class differences on related consequences after 3 months among college students engaging in SAM use (77.08% White, 51.67% female). Class indicators were 10 person-level substance use variables derived from repeated daily surveys.

Results

Results yielded a three-class solution: Heavy Alcohol, Cannabis, and SAM (Heavy Use, n = 105); Heavy Alcohol-Light Cannabis (n = 75); and Light Alcohol-Heavy Cannabis (n = 60). There were significant person-level differences between classes on all substance use indicators (e.g., quantity and frequency of alcohol, cannabis, and SAM) but not sex or race/ethnicity. At 3-month follow-up, the Heavy Use class endorsed more SAM consequences than the other classes. The Heavy Use class did not differ on alcohol or cannabis consequences compared to the Heavy Alcohol-Light Cannabis or Light Alcohol-Heavy Cannabis classes, respectively. The Light Alcohol-Heavy Cannabis class endorsed the fewest alcohol consequences. The Heavy Alcohol-Light Cannabis class endorsed the fewest cannabis consequences.

Conclusions

Findings highlight distinct patterns of co-use and their association with consequences at follow-up. Heavy alcohol or cannabis use was associated with consequences for that substance, but heavy use of only one substance was not indicative of SAM-specific consequences.

The role of sex in daily levels of high-risk alcohol and cannabis co-use

Background

Co-use of alcohol and cannabis is highly prevalent and may be associated with negative outcomes. The intersection between alcohol and cannabis use remains poorly understood. The present study assessed this intersection and the moderating effects of sex on the daily levels of high-risk alcohol and cannabis co-use.

Methods

A secondary analysis of an experimental pharmacology study specifically designed to recruit individuals using both alcohol and cannabis was conducted. Thirty-three non-treatment seeking subjects (19 M/14F) reporting high-risk levels of alcohol and cannabis use completed a 30-day Timeline Follow-back (TLFB) assessment for alcohol and cannabis use, resulting in a total of N = 990 observations. Logistic models tested the probability of same day cannabis use as predicted by alcohol use (any use, total drinking, and binge drinking), sex, and alcohol use by sex interactions.

Results

Drinking any alcohol on a given day was associated with a significant increase in the likelihood of same-day cannabis use (b = 0.61, p = 0.001) as was amount of alcohol consumed on a given day (b = 0.083, p = 0.012). These relations were significantly moderated by sex (b = 1.58, p<0.001; b = 0.14, p = 0.044). Male-identifying individuals demonstrated an increased probability of concurrent cannabis use with any alcohol use on a given day, and this relationship increased linearly as the number of drinks consumed increased.

Conclusions

The present study investigated the patterns associated with co-using alcohol and cannabis in individuals reporting high-risk levels of both alcohol and cannabis use. The sex-dependent findings suggest that males are at higher risk for co-using alcohol and cannabis compared with females.

Daily Relations Among Alcohol and Cannabis Co-Use, Simultaneous Use, and Negative Consequences: A Day-Level Latent Profile Analysis

Objective

Concurrent and simultaneous cannabis and alcohol co-use confers risk for daily negative alcohol consequences. However, studies often treat co-use as a dichotomy, precluding examination of higher- and lower-risk co-use days. Additionally, little is known about specific alcohol consequences associated with daily co-use. Therefore, the current study 1) differentiated days based upon alcohol consumption, co-use, and simultaneous use, and 2) tested whether certain day-level use patterns conferred risk for daily alcohol consequences.

Methods

College student co-users (N=489) completed an online Timeline Followback, reporting daily alcohol consumption, negative alcohol consequences, concurrent cannabis and alcohol co-use, and simultaneous co-use (SAM) on drinking days over the past month. Day-Level Latent Profile Analysis differentiated days based upon drinking quantity, co-use, and simultaneous use, and tested whether patterns of use conferred risk for overall and specific negative alcohol consequences.

Results

Four day-level profiles emerged, including moderate consumption of alcohol-only days (57.5%), moderate consumption SAM use days (29.1%), higher consumption alcohol-only days (7.4%), and higher consumption SAM use days (6%). Higher consumption SAM use days were associated with more negative alcohol consequences than all other days; however, higher consumption SAM use days differed from higher consumption alcohol-only days in acute dependence symptoms. Higher consumption alcohol-only days were associated with more negative alcohol consequences than moderate consumption SAM days, particularly those that were action-oriented (i.e., dependence symptoms, blackout drinking, impaired control, risky behavior, social/interpersonal consequences).

Conclusions

Findings suggest that there are in fact lower-risk co-use days, and that links with unique negative alcohol consequences depend on levels of alcohol consumption and co-use.

Subjective effects of simultaneous alcohol and cannabis versus alcohol-only use: A qualitative analysis

OBJECTIVE

Theoretical models of addictive behavior suggest that subjective effects serve as a mechanism through which substance use disorders develop. However, little is known about the subjective effects of simultaneous alcohol and cannabis use, particularly whether simultaneous use (a) heightens specific subjective effects or (b) is related to unique subjective effects relative to single-substance effects. The present study used formative, qualitative data analysis to examine patterns of responses within open-answer text response data on subjective effects of simultaneous use.

METHOD

College students who simultaneously use alcohol and cannabis (N = 443; 68.2% female) were asked to describe how alcohol effects differ on simultaneous alcohol and cannabis use versus alcohol-only use days.

RESULTS

Conventional content analysis revealed nine concepts related to simultaneous (vs. alcohol-only) use subjective effects including as follows: (a) increased/decreased impairment, (b) low arousal/relaxation, (c) balancing/replacement effects, (d) "cross-faded" effects, (e) little-to-no differences, (f) altered sensation and perception, (g) increased negative affective states, (h) increased appetite, and (i) increased/decreased negative consequences. Increased impairment (N = 191) and increased relaxation (N = 110) were the most often endorsed subjective effects, followed by decreased impairment (N = 55), balancing/replacement effects (N = 50) and cross-faded/enhancement effects (N = 44).

CONCLUSIONS

Subjective effects from simultaneous use largely map onto domains of single-substance alcohol and cannabis effects (e.g., relaxation, sociability, cognitive/behavioral impairment), but also include distinct domains related to simultaneous use (e.g., balancing/replacement effects, altered sensation and perception). Future quantitative research is needed to validate measures of subjective effects from simultaneous use and their relations with use behavior. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Daily-level simultaneous alcohol and marijuana use and its associations with alcohol use, marijuana use, and negative consequences in a young adult community sample

BACKGROUND

Simultaneous alcohol and marijuana (SAM) use has been associated with greater alcohol use and consequences at the daily level, but limited research has examined SAM use in relation to marijuana use and its consequences. This study tested daily associations between SAM use and four outcomes: alcohol use (number of drinks), marijuana use (hours high), negative alcohol consequences, and negative marijuana consequences.

METHODS

A community sample of young adults [ages 18-25, mean (SD) = 21.61 (2.17) years] with recent alcohol and SAM use was recruited (N = 409; 50.9% female; 48.2% non-Hispanic/Latinx White). Participants completed a baseline survey and six 2-week bursts of daily surveys (81.1% of morning surveys completed) and reported on substance use and negative substance-related consequences. Multilevel modeling was used to test the main aims and to explore each specific consequence.

RESULTS

Among days with any alcohol use, SAM use days were associated with consuming more drinks and experiencing more total negative alcohol-related consequences than non-SAM use days. Among days with any marijuana use, SAM use days were associated with more hours being high than non-SAM use days. Exploratory models showed that SAM use was related to five specific alcohol-related consequences and two specific marijuana-related consequences.

CONCLUSIONS

These findings build upon prior research by showing that SAM use days are linked to consuming more drinks, reporting more hours being high from marijuana, and experiencing more total alcohol-related consequences even after controlling for the number of drinks, the number of hours high, any tobacco/nicotine use, and any other substance use. SAM use was also associated with a greater likelihood of experiencing some specific consequences related to alcohol and marijuana. The findings underscore the need for additional research on SAM use and marijuana-related outcomes.

Dynamic relations among simultaneous alcohol and cannabis use, subjective responses, and problem drinking during naturally occurring drinking episodes

BACKGROUND

Simultaneous alcohol and cannabis use (SAM) is associated with riskier drinking. However, little is known regarding mechanisms of risk during drinking episodes. The current study tested whether subjective responses to simultaneous vs. alcohol-only use (i.e., high arousal positive/reward, high arousal negative/aggression, low arousal positive/relaxation, low arousal negative/impairment) were mechanisms through which SAM use was associated with daily drinking.

METHODS

Emerging adults who co-use alcohol and cannabis (N=85) completed 21 days of ecological momentary assessment with drink-contingent reports during drinking episodes. Participants reported on their simultaneous use and current subjective effects during drink reports and past-night total drinks consumed and negative consequences experienced the next morning. Three-level multilevel models (momentary, daily, person level) tested whether SAM use predicted subjective responses, and whether subjective responses mediated associations between SAM use, heavier drinking and negative consequences.

RESULTS

At the momentary and day-level, SAM (vs. alcohol-only) use predicted increased high arousal positive/rewarding, low arousal positive/relaxing, and low arousal negative/impairing subjective effects. SAM use indirectly predicted heavier day-level drinking and further negative consequences through high arousal positive/rewarding response. SAM use also indirectly predicted day-level negative consequences through low arousal negative/impairing response. At the person-level, more frequent SAM use predicted higher person-average high arousal positive/rewarding and low arousal positive/relaxing responses, and high arousal positive/rewarding response mediated relation between SAM frequency and heavier drinking.

CONCLUSIONS

Simultaneous use was associated with reward, relief, and impairment, and reward and impairment were mechanisms of risk between SAM use and riskier drinking. Findings may inform theory and just-in-time interventions seeking to reduce alcohol misuse.

Patterns of Accidental and Intentional Alcohol Intoxication Initiation among French Young Adults: A Survival Analysis

Background: The aim of the study was to explore patterns of accidental and intentional intoxication among French young adults who use alcohol. Methodology: The study draws on data from the 2017 French Health Barometer. Cox proportional hazards models were used to explore the factors associated with accidental and intentional alcohol intoxication initiation. Covariates studied were gender, age, employment status, consultation for mental health problems, depression lasting at least two weeks in the past 12 months, and previous tobacco or cannabis use as time-dependent variables. Results: Women accounted for 50.4% of our sample, and the mean age of respondents was 29.2 (standard deviation = 6.3). The prevalence of lifetime accidental intoxication among alcohol users was 77.0% and 17.3% for intentional intoxication. Kaplan-Meier analyses showed that the first intentional intoxication experience occurred later than the first accidental intoxication. Factors associated with accidental intoxication initiation in multivariate analyses were: male gender, age under 30, previous use of tobacco and cannabis, experiencing depression that lasted at least two weeks in the past 12 months, and having consulted for mental health problems in the past 12 months. Economically inactive people and students had a lower risk of experiencing accidental intoxication than those who were employed. Similar correlates were found for intentional intoxication, but being economically inactive was more strongly associated with intentional intoxication initiation. Conclusions: These results suggest the strong potential for alcohol consumption to become hazardous, particularly if tobacco or cannabis are also used. Prevention programs on alcohol must target consumers at the earliest stage and integrate other substances often used in a festive context.

Cannabis Recreational Legalization and Prevalence of Simultaneous Cannabis and Alcohol Use in the United States

BACKGROUND

Simultaneous cannabis/alcohol use, using both substances within a short time interval so that their effects overlap, has a greater risk of potential negative consequences than single-substance use and is more common in younger age. Relationships between recreational cannabis laws (RCLs) and changes in simultaneous cannabis/alcohol use prevalence remain untested.

OBJECTIVE

To examine trends in simultaneous cannabis/alcohol use from 2008 to 2019, and investigate associations between implementation of RCLs (i.e., presence of active legal dispensaries or legal home cultivation) and simultaneous cannabis/alcohol use in the United States (U.S.).

DESIGN

Repeated cross-sectional samples from the 2008-2019 U.S. National Survey on Drug Use and Health (NSDUH).

PARTICIPANTS

Respondents (51% female) aged 12 and older.

INTERVENTIONS

Changes in simultaneous cannabis/alcohol use before and after RCL implementation (controlling for medical cannabis law implementation) were compared in different age groups (12-20, 21-30, 31-40, 41-50, 51+), using adjusted multi-level logistic regression with state random intercepts and an RCL/age group interaction.

MEASUREMENTS

Self-reported simultaneous cannabis/alcohol use.

RESULTS

From 2008 to 2019, the overall prevalence of simultaneous cannabis/alcohol use declined among those aged 12-20 but increased in adults aged 21+. Model-based simultaneous cannabis/alcohol use prevalence increased after RCL implementation among respondents aged 21-30 years (+1.2%; aOR= 1.15 [95%CI = 1.04-1.27]), 31-40 years (+1.0; 1.15 [1.04-1.27]), and 41-50 years (+1.75; 1.63 [1.34-1.98]), but not in individuals aged <21 or 51+ years.

CONCLUSIONS

Implementation of recreational cannabis policies resulted in increased simultaneous use of cannabis and alcohol, supporting the complementarity hypothesis, but only among adults aged 21+. Efforts to minimize harms related to simultaneous cannabis/alcohol use are critical, especially in states with RCLs. Future studies should investigate cultural norms, perceived harm, and motives related to simultaneous use.

Alcohol & cannabinoid co-use: Implications for impaired fetal brain development following gestational exposure

Alcohol and marijuana are two of the most consumed psychoactive substances by pregnant people, and independently, both substances have been associated with lifelong impacts on fetal neurodevelopment. Importantly, individuals of child-bearing age are increasingly engaging in simultaneous alcohol and cannabinoid (SAC) use, which amplifies each drug's pharmacodynamic effects and increases craving for both substances. However, to date, investigations of prenatal polysubstance use are notably limited in both human and non-human populations. In this review paper, we will address what is currently known about combined exposure to these substances, both directly and prenatally, and identify shared prenatal targets from single-exposure paradigms that may highlight susceptible neurobiological mechanisms for future investigation and therapeutic intervention. Finally, we conclude this manuscript by discussing factors that we feel are essential in the consideration and experimental design of future preclinical SAC studies.

The role of alcohol and cannabis co-use in drinking rate and its impact on consequences

BACKGROUND

The impact of alcohol and cannabis co-use on college student drinking and related outcomes is complex. Specific characteristics or patterns of co-use events beyond drinking quantity may be important to the experience of consequences. The present study used repeated daily surveys to examine the association between co-use (versus use of alcohol only) and drinking rate on negative consequences.

METHODS

The sample included 318 college students (M_age  = 19.8, 47% female, 76% non-Hispanic White) who were co-users of alcohol and cannabis, recruited from three U.S. college campuses. Participants completed 56 days of data collection (number of drinking days ranged from 1 to 38). Two measures of drinking rate were examined: (1) daily rate (number of drinks divided by number of hours spent drinking per day); and (2) peak hour rate (maximum number of drinks consumed in a single hour) to account for anomalous drinking days of long duration. Generalized linear mixed models examined: (1) associations of co-use with peak hour rate (model 1a) and daily rate (model 1b); (2) associations of peak hour rate (model 2a) and daily rate (model 2b) with experiencing any negative consequence; and (3) interactions of co-use with peak hour rate (model 3a) and daily rate (model 3b) on experiencing a consequence.

RESULTS

Co-use was positively associated with peak hour rate but not daily rate. Both peak hour and daily rate positively predicted likelihood of experiencing a negative consequence. The interaction of both peak hour and daily rate by co-use was significant such that the association of rate with experiencing a consequence was stronger on alcohol-only days compared to co-use days.

CONCLUSIONS

Daily drinking rate and peak hour drinking rate are unique and should be considered when discussing drinking patterns. Both predict negative consequences and may be important aspects of interventions for negative drinking-related outcomes among college students.

Nuanced relations between simultaneous alcohol and cannabis use motives and negative consequences among college students: The role of multiple product use

Simultaneous alcohol and marijuana (SAM) use is common, but it exacerbates negative consequences. Individuals use alcohol and cannabis products in different ways and have distinct reasons for use. The present study examines day-level effects of motives on consequences on SAM-use days, accounting for consumption, and tests whether using multiple alcohol (e.g., beer + liquor) and/or cannabis (e.g., concentrate + leaf) products on the same day mediates these relations. College students engaging in SAM use at least once in the past month (N = 281; Mage = 20.17) completed two bursts of 28 consecutive days of data collection. We examined within-person effects of motives (effect-enhancement, social, offered [it was offered], coping) on number of negative consequences and on experiencing hangover, nausea, or blackout; and indirect effects via two concurrent mediators: using multiple alcohol products and multiple cannabis products. Total effect models showed effect-enhancement motives were related to nausea, social motives to number of total consequences and hangover, and coping motives to blackout. Effect-enhancement, social, and offered motives evinced significant indirect effects on consequence outcomes via multiple alcohol, but not cannabis, product use. Coping motives did not exhibit significant indirect effects, and were related to multiple cannabis, but not alcohol, product use, although all other motives were related to both mediators. Findings support recent work demonstrating within-person relations between social motives and negative consequences on SAM-use days. Limiting the number of alcohol products consumed on SAM-use days may be beneficial, particularly for young adults using to enhance intoxication or for social reasons. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The effects of oral and vaporized cannabis alone, and in combination with alcohol, on driving performance using the STISIM driving simulator: A two-part, double-blind, double-dummy, placebo-controlled, randomized crossover clinical laboratory protocol

The legalization of cannabis for medicinal and non-medicinal purposes, and the corresponding increase in diversity of cannabis products, has resulted an urgent need for cannabis regulatory science. Among the most pressing needs is research related to impairment due to cannabis exposure, especially on driving performance. The present project was designed to evaluate the impact of oral and vaporized cannabis, when administered alone or in combination with alcohol, on simulated driving performance (STISIM driving simulator), cognitive/psychomotor ability, and field sobriety performance. Healthy adults will complete two, double-blind, double-dummy, placebo-controlled, randomized crossover clinical laboratory studies, one with oral cannabis (16 men/16 women) and the second with vaporized cannabis (16 men/16 women). In each study, participants will complete seven experimental sessions during which acute doses of placebo or high Δ9-THC cannabis containing 0, 10, or 25 mg Δ9-THC will be administered both alone and in combination with placebo or alcohol-containing beverages (target breath alcohol concentrations, BAC, of 0.0% or 0.05%). A positive control session (i.e., alcohol at target BAC of 0.08% with placebo cannabis) will also be completed. Simulated driving performance tests (available for download; see Methods), field sobriety assessments, subjective drug effect questionnaires, a mobile device impairment test (DRUID app), and collection of whole blood specimens will be completed repeatedly during each session. Linear mixed models will be used to test for differences across experimental conditions and a priori planned comparisons will be used to determine differences between conditions of interest (e.g., cannabis alone vs cannabis with alcohol). This research is designed to extend prior studies of cannabis and alcohol on driving performance by using oral and vaporized routes of cannabis administration. By increasing understanding of impairment associated with co-use of alcohol and these novel forms of cannabis, this research could inform impairment detection standards for cannabis and alcohol and have important implications for law enforcement, public policy decisions regarding accessibility of these substances, and education of the general population who may use cannabis and/or alcohol. Lastly, this manuscript provides interested researchers with access to the simulated driving scenarios and data extraction tools developed for this study as a means of facilitating future cross-study comparisons, which is important given the heterogeneity in methods used across laboratories in prior research.

Combined alcohol and cannabinoid exposure leads to synergistic toxicity by affecting cerebellar Purkinje cells

Combined use of cannabis and alcohol results in greater psychoactive toxicity than either substance alone, but the underlying central mechanisms behind this worsened outcome remain unclear. Here we show that the synergistic effect of Δ⁹-tetrahydrocannabinol (THC) and ethanol on motor incoordination in mice is achieved by activating presynaptic type 1 cannabinoid receptors (CB₁R) and potentiating extrasynaptic glycine receptors (GlyR) within cerebellar Purkinje cells (PCs). The combination of ethanol and THC significantly reduces miniature excitatory postsynaptic current frequency in a CB₁R-dependent manner, while increasing the extrasynaptic GlyR-mediated chronic chloride current, both leading to decreased PC activity. Ethanol enhances THC actions by boosting the blood-brain-barrier permeability of THC and enriching THC in the cell membrane. Di-desoxy-THC, a designed compound that specifically disrupts THC-GlyR interaction without affecting the basic functions of CB₁R and GlyR, is able to restore PC function and motor coordination in mice. Our findings provide potential therapeutic strategies for overcoming the synergistic toxicity caused by combining cannabis and alcohol use.

Correlates of high phosphatidylethanol (PEth) levels and their concordance with self-reported heavy alcohol consumption among men who have sex with men who binge drink alcohol

BACKGROUND

Heavy alcohol use, including binge drinking, is associated with high morbidity and mortality among men who have sex with men (MSM). Self-reported alcohol measures may lead to inaccurate estimates due to recall and social desirability biases. Objective alcohol biomarkers like phosphatidylethanol (PEth) can be used to corroborate self-report and could help to inform treatment approaches and research strategies for alcohol using MSM.

METHODS

From 2015 to 2020, alcohol using MSM ≥18 years were enrolled in a randomized controlled trial evaluating the efficacy of naltrexone in reducing binge drinking. Using this trial's baseline data, we applied multivariable logistic regression to identify the correlates of high PEth levels (i.e., ≥87 ng/ml) and concordance between PEth levels and self-reported heavy drinking.

RESULTS

Of 118 MSM, 64% had PEth levels ≥87 ng/ml and 72% had PEth levels that were concordant with self-reported heavy alcohol use. Factors significantly associated in separate models with elevated PEth levels were income ≥$60,000 (adjusted odds ratio [aOR] = 4.09; 95% CI = 1.13 to 14.82), being employed (aOR = 4.04; 95% CI = 1.45 to 11.32), episodic cannabis use (aOR = 4.63; 95% CI = 1.27 to 16.92), and any alcohol/substance use prior to or during anal intercourse (aOR = 2.52; 95% CI = 1.08 to 5.90). Living with HIV was associated with significantly lower odds of elevated PEth levels (aOR = 0.23; 95% CI = 0.09 to 0.61). Factors associated with significantly higher concordance between PEth levels and self-reported heavy alcohol use included at least weekly use of poppers (aOR = 6.41; 95% CI = 1.27 to 32.28) and polysubstance use (aOR = 2.53; 95% CI = 1.02 to 6.27). Living with HIV was associated with lower odds of concordance (aOR = 0.36; 95% CI = 0.14 to 0.97).

CONCLUSIONS

PEth may enhance the detection of heavy drinking among MSM, including the identification of subpopulations that may benefit from targeted alcohol reduction interventions. However, PEth values for MSM living with HIV showed modest concordance with self-reported alcohol use and may need to be supplemented with additional biomarkers or evaluated against a different cutoff.

Unplanned versus planned simultaneous alcohol and cannabis use in the daily lives of a predominantly white college student sample: What are the motives, contexts, and outcomes?

OBJECTIVE

Simultaneous alcohol and cannabis use is common among college students and associated with more consumption and consequences compared to single-substance use. This study examined occasions of simultaneous use and compared planned occasions to unplanned occasions with respect to motives, contexts, consumption, and consequences.

METHOD

College student simultaneous users (N = 341; 53% women; 74% White) completed five daily surveys for 54 days. Mixed-effects models examined motives and contexts of simultaneous use occasions as a function of whether alcohol and cannabis use were (a) both planned versus (b) unplanned, no use planned, or (c) unplanned, single-substance use planned and whether alcohol and cannabis consumption and negative simultaneous use-related consequences varied across planned versus unplanned occasions.

RESULTS

Social and enhancement motives were related to planned simultaneous use; offered and coping motives were associated with planned single-substance use that became simultaneous use (vs. planned simultaneous use). Compared to unplanned use, planned simultaneous use was negatively associated with using at home or alone, and positively associated with using with others, more intoxicated people, and more people using cannabis. Planned simultaneous use was associated with more alcohol and cannabis consumption. No significant differences were found for negative consequences.

CONCLUSIONS

Planned simultaneous use was motivated by social and enhancement reasons, whereas planned single-substance use that became simultaneous use was more likely motivated by offers or for coping. Planned simultaneous use resulted in greater consumption, but not negative consequences. Results provide specific motives and contexts associated with unplanned and planned simultaneous use to be incorporated into real-time interventions. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

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

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

Daily fluctuations in drinking intensity: Links with vaping and combustible use of nicotine and marijuana

BACKGROUND

Whether alcohol use intensity on a given day is linked with nicotine or marijuana use that same day is not well known, nor are links of drinking intensity with different modes of nicotine and marijuana use. This study examined these within-person links across 14 days in a national sample of young adults (YAs).

METHODS

Past 30-day drinkers participating in the U.S. nationally representative Monitoring the Future study of 12th graders in 2018, who also reported alcohol use during a 14-day data collection one year later in the Young Adult Daily Life Study in 2019, were included (N = 487). Weighted multilevel modeling estimated within- and between-person associations of drinking intensity with cigarette smoking, nicotine vaping, marijuana smoking, and marijuana vaping.

RESULTS

Within-person fluctuations in drinking intensity on a given day were associated with cigarette smoking, nicotine vaping, and marijuana smoking, but not marijuana vaping. There were significant between-person associations of means of drinking intensity and each outcome, except for cigarette smoking.

CONCLUSION

Drinking intensity on a given day was associated with multiple modes of nicotine use and marijuana smoking that day. Nicotine and marijuana use remain critical areas of concern for public health, and future research and interventions should consider the comorbidity of drinking intensity and multiple modes of nicotine and marijuana use. Focusing on the same-day use of alcohol may provide a tailored avenue for preventing and reducing nicotine and marijuana emerging trends among YAs.

Patterns of Cannabis and Alcohol Co-Use: Substitution Versus Complementary Effects

PURPOSE

The purpose of this review is to discuss the literature regarding the concurrent use (co-use) of alcohol and cannabis and competing hypotheses as to whether cannabis acts as a substitute for (i.e., replacing the effects of alcohol, resulting in decreased use) or a complement to (i.e., used to enhance the effects of alcohol, resulting in increased use) alcohol. The impact of cannabis use on alcohol-related outcomes has received increased attention in the wake of ongoing legalization of cannabis for both medical and recreational purposes. Evidence for both hypotheses exists in the literature across a broad range of data collection methods and samples and is carefully reviewed here. In addition, various mechanisms by which cannabis may act as an alcohol substitute or complement are explored in depth with the goal of better understanding equivocal findings.

SEARCH METHODS

This review includes articles that were identified from a search for studies on alcohol and cannabis co-use, with a specific focus on studies exploring complementary versus substitution aspects of co-use. Search terms were included in Google Scholar, PsycINFO, MEDLINE, and Web of Science. Eligible studies were those that measured alcohol and cannabis co-use in human samples in laboratory, survey, or ecological momentary assessment studies, or that directly referenced substitution or complementary patterns of use.

SEARCH RESULTS

Search results returned 650 articles, with 95 meeting inclusion criteria.

DISCUSSION AND CONCLUSIONS

Results of this review reveal compelling evidence for both substitution and complementary effects, suggesting nuanced yet significant distinctions across different populations examined in these studies. Several mechanisms for the impact of cannabis use on alcohol-related outcomes are identified, including patterns and context of co-use, timing and order of use, cannabinoid formulation, pharmacokinetic interactions, and user characteristics (including diagnostic status), all of which may influence substitution versus complementary effects. This review will inform future research studies examining this topic in both clinical and community samples and aid in the development of treatment and prevention efforts targeting those populations most vulnerable to negative consequences of co-use. Finally, this review highlights the need for additional research in more diverse samples and the use of mixed-methods designs to examine both pharmacological and contextual influences on co-use.

The Synaptic Interactions of Alcohol and the Endogenous Cannabinoid System

PURPOSE

A growing body of evidence has implicated the endocannabinoid (eCB) system in the acute, chronic, and withdrawal effects of alcohol/ethanol on synaptic function. These eCB-mediated synaptic effects may contribute to the development of alcohol use disorder (AUD). Alcohol exposure causes neurobiological alterations similar to those elicited by chronic cannabinoid (CB) exposure. Like alcohol, cannabinoids alter many central processes, such as cognition, locomotion, synaptic transmission, and neurotransmitter release. There is a strong need to elucidate the effects of ethanol on the eCB system in different brain regions to understand the role of eCB signaling in AUD.

SEARCH METHODS

For the scope of this review, preclinical studies were identified through queries of the PubMed database.

SEARCH RESULTS

This search yielded 459 articles. Clinical studies and papers irrelevant to the topic of this review were excluded.

DISCUSSION AND CONCLUSIONS

The endocannabinoid system includes, but is not limited to, cannabinoid receptors 1 (CB₁), among the most abundantly expressed neuronal receptors in the brain; cannabinoid receptors 2 (CB₂); and endogenously formed CB₁ ligands, including arachidonoylethanolamide (AEA; anandamide), and 2-arachidonoylglycerol (2-AG). The development of specific CB₁ agonists, such as WIN 55,212-2 (WIN), and antagonists, such as SR 141716A (rimonabant), provide powerful pharmacological tools for eCB research. Alcohol exposure has brain region-specific effects on the eCB system, including altering the synthesis of endocannabinoids (e.g., AEA, 2-AG), the synthesis of their precursors, and the density and coupling efficacy of CB₁. These alcohol-induced alterations of the eCB system have subsequent effects on synaptic function including neuronal excitability and postsynaptic conductance. This review will provide a comprehensive evaluation of the current literature on the synaptic interactions of alcohol exposure and eCB signaling systems, with an emphasis on molecular and physiological synaptic effects of alcohol on the eCB system. A limited volume of studies has focused on the underlying interactions of alcohol and the eCB system at the synaptic level in the brain. Thus, the data on synaptic interactions are sparse, and future research addressing these interactions is much needed.

Simultaneous Alcohol and Marijuana Use Among Young Adults: A Scoping Review of Prevalence, Patterns, Psychosocial Correlates, and Consequences

BACKGROUND

Alcohol and marijuana are commonly used by young adults, and use of both substances, particularly at the same time, is prevalent among this population. Understanding the prevalence, patterns, correlates, and consequences of simultaneous alcohol and marijuana (SAM) use is important to inform interventions. However, this literature is complicated by myriad terms used to describe SAM use, including use with overlapping effects and same-day co-use.

OBJECTIVES

This scoping review identifies and describes the peer-reviewed literature focused on SAM use by young adults and distinguishes simultaneous use from same-day co-use of alcohol and marijuana. This review also provides a narrative summary of the prevalence of SAM use, patterns of SAM and other substance use, psychosocial correlates, and consequences of SAM use.

ELIGIBILITY CRITERIA

This review is limited to papers written in English and published in peer-reviewed journals between January 2000 and August 2021. It includes papers assessing simultaneous use or same-day co-use of alcohol and marijuana among young adults ages 18 to 30. Review papers, qualitative interviews, experimental lab studies, policy work, toxicology or medical reports, and papers focused on neurological outcomes are excluded.

SOURCES OF EVIDENCE

PubMed, PsycINFO, and Web of Science databases were searched. Databases were selected and the search strategy developed in consultation with an information specialist.

CHARTING METHODS

A data charting form was utilized to specify which information would be extracted from included papers. Eight categories of data were extracted: (1) research questions and hypotheses; (2) sample characteristics; (3) study procedures; (4) definition of SAM use; (5) prevalence of SAM use; (6) patterns of SAM and other substance use; (7) psychosocial correlates of SAM use; and (8) consequences of SAM use.

RESULTS

A total of 1,282 papers were identified through initial search terms. Through double-blind title/abstract screening and full-text review, the review was narrowed to 74 papers that met review inclusion criteria. Review of these papers demonstrated that SAM use was prevalent among young adults, particularly among those who reported heavier quantities and more frequent use of alcohol and marijuana. Enhancement-related motives for use were consistently positively associated with SAM use. SAM use was associated with greater perceived positive and negative consequences of alcohol and/or marijuana use. Inconsistencies in prevalence, patterns, correlates, and consequences were found between studies, which may be due to large variations in measurement of SAM use, populations studied, methodological design (e.g., cross-sectional vs. intensive longitudinal), and the covariates included in models.

CONCLUSIONS

The literature on simultaneous use and same-day co-use of alcohol and marijuana has expanded rapidly. Of the 74 included papers (61 on SAM use; 13 on same-day co-use), 60 papers (47 on SAM use; 13 on same-day co-use) were published within the last 5 years. Future research focusing on the ways in which SAM use confers acute risk, above and beyond the risks associated with separate consumption of alcohol and marijuana, is needed for understanding potential targets for intervention.

Sex-dependent effects of alcohol administration on the urge to use cannabis

Alcohol and cannabis couse is highly prevalent and associated with various negative consequences. The likelihood of same day couse is high, especially among men, however, underlying mechanisms to their couse and its sex-dependent nature remain poorly understood. This study aims to elucidate the effects of controlled alcohol administration on the urge to use cannabis and considers sex-dependent effects. A community sample of non-treatment-seeking heavy drinkers (N = 37, 46% female) reporting cannabis use in the past 6 months completed an alcohol administration paradigm. Participants rated their urge to use cannabis and drink alcohol at baseline and at rising levels of breath alcohol concentration (BrAC). Mixed model analyses examined the effects of BrAC, sex, and their interaction on craving for cannabis. The relationships across urge for cannabis, urge for alcohol, and subjective responses to alcohol were also tested. There was a significant BrAC × Sex interaction on the urge to use cannabis, such that males reported increases in the urge to use cannabis at rising BrACs but females did not. Urge for alcohol significantly predicted urge for cannabis across rising levels of BrAC and this relationship was stronger in males than in females. Lastly, stimulation, but not sedation, during alcohol administration was positively associated with the urge for cannabis. Overall, these results suggest that the pharmacological effects of alcohol on the urge to use cannabis are sex-dependent and that the stimulant effects of alcohol are associated with a higher urge for cannabis. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Cannabinoid Use Among Liver Transplant Recipients

The effect of cannabinoids on liver transplant outcomes is an area of active research. We aimed to investigate marijuana (MJ) and cannabidiol (CBD) use among liver transplant recipients at the University of Colorado Hospital (UCH), specifically prevalence, habits, and predictors of use. Liver transplant recipients followed at UCH with valid email addresses were sent an informed consent postcard and survey invitation. This exploratory survey was conducted using REDCap. IBM SPSS Statistics software was used for statistical analysis. Of 1227 recipients who were sent surveys, 538 people responded. On average, respondents were 59 years old, with 63.7% male and 81.7% White. Hepatitis C virus (HCV; 30.4%) and alcohol use (17.7%) were the most common etiologies of liver disease. Among respondents, 23.8% reported current MJ use. Methods of use included smoking (72.4%), ingestion (55.3%), and vaporization (31.7%). Top reasons for MJ use were recreation (56.5%), anxiety (54.8%), and pain (53.2%). Among respondents, 21.0% currently used CBD, usually in the form of creams or lotions (58.9%) and to relieve pain (84.9%) and anxiety (31.1%). In multivariable analysis, age (odds ratio [OR], 0.941; 95% confidence interval [CI], 0.923-0.959; P < 0.001), diabetes mellitus (OR, 0.357; 95% CI, 0.171-0.746; P = 0.01), HCV cirrhosis (OR, 3.949; 95% CI, 2.281-6.835; P < 0.001), alcohol-related cirrhosis (OR, 2.101; 95% CI, 1.202-3.671; P = 0.01), and current tobacco use (OR, 2.918; 95% CI, 1.065-7.990; P = 0.04) were significant predictors of MJ use. Our study shows that cannabinoid use after liver transplant is common. MJ use is associated with decreasing age, alcohol-related and HCV cirrhosis, and tobacco use. Anxiety, pain, and recreation were top reasons for its use. Transplant teams should address reasons why their patients use MJ and CBD and develop programs to mitigate anxiety and pain after transplant. Further studies are needed to examine effects of cannabinoids on liver transplant outcomes.

Alcohol and Cannabis Use Disorder Symptom Severity, Conduct Disorder, and Callous-Unemotional Traits and Impairment in Expression Recognition

Background: Alcohol and cannabis are commonly used by adolescents in the United States. Both alcohol use disorder (AUD) and cannabis use disorder (CUD) have been associated with reduced emotion expression recognition ability. However, this work has primarily occurred in adults and has not considered neuro-cognitive risk factors associated with conduct problems that commonly co-occur with, and precede, substance use. Yet, conduct problems are also associated with reduced emotion expression recognition ability. The current study investigated the extent of negative association between AUD and CUD symptom severity and expression recognition ability over and above any association of expression recognition ability with conduct problems [conduct disorder (CD) diagnostic status]. Methods: In this study, 152 youths aged 12.5-18 years (56 female; 60 diagnosed with CD) completed a rapid presentation morphed intensity facial expression task to investigate the association between relative severity of AUD/CUD and expression recognition ability. Results: Cannabis use disorder identification test (CUDIT) scores were negatively associated with recognition accuracy for higher intensity (particularly sad and fearful) expressions while CD diagnostic status was independently negatively associated with recognition of sad expressions. Alcohol use disorder identification test (AUDIT) scores were not significantly associated with expression recognition ability. Conclusions: These data indicate that relative severity of CUD and CD diagnostic status are statistically independently associated with reduced expression recognition ability. On the basis of these data, we speculate that increased cannabis use during adolescence may exacerbate a neuro-cognitive risk factor for the emergence of aggression and antisocial behavior.

Real-world simultaneous alcohol and cannabis use: An ecological study of situational motives and social and physical contexts

OBJECTIVE

Given the adverse outcomes associated with simultaneous alcohol and marijuana (SAM) use, understanding factors that give rise to occasions of simultaneous use is critical. This study examines the relationships between situational motives and contexts and three situational outcomes: simultaneous alcohol and marijuana use (SAM) use versus cannabis-only use, number of cannabis uses, and subjective effects.

METHOD

Past-month SAM users (n = 341; 52% female; 75% White; 10% Latinx/Hispanic; age 18-24) from three U.S. college campuses completed 8 weeks of surveys up to five times a day. Three-level generalized linear mixed-effects models tested the effects of situational motives and social and physical contexts on occasion type (SAM vs. cannabis-only), cannabis use, and subjective effects.

RESULTS

Situational social and enhancement motives were related to greater odds of SAM relative to cannabis-only use; expansion motives were reported more often on cannabis-only occasions. Using with others and at friends' places, being with others consuming cannabis, and being with others who are intoxicated were more likely when combining alcohol with cannabis. Increased number of cannabis uses and subjective effects in a social context were evident only on cannabis-only occasions. Using alone and using at home were greater on cannabis-only occasions and were associated with lower cannabis use and subjective effects.

CONCLUSIONS

The combination of alcohol and cannabis use occurs during social situations and when motivated by positive reinforcement but number of cannabis uses is not increased when consuming cannabis with alcohol in social situations. Characterizing the complex interplay of situational factors that contribute to risky use will inform interventions. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Effect of alcohol, tobacco, and cannabis co-use on gray matter volume in heavy drinkers

OBJECTIVE

Alcohol, tobacco, and cannabis are the three most frequently used drugs in the United States and co-use is common. Alcohol, tobacco, and cannabis use has been separately associated with altered brain structure, and alcohol and tobacco co-use results in decreases in gray matter volume. Less is known about the effect of alcohol and cannabis co-use, and alcohol, tobacco, and cannabis tri-use. Therefore, this study examined the effect of co- and tri-use on gray matter volume, a measure of brain cell density, in heavy drinkers.

METHOD

Heavy drinkers (n = 237; 152m/85f; age = 32.52; white = 111; black = 28; Latino = 9; American Indian = 2; Pacific Islander = 4; Asian = 59; mixed = 15; other = 9) were classified into four groups based on their alcohol, tobacco, and cannabis use: alcohol only users (n = 70), alcohol and tobacco co-users (n = 90), alcohol and cannabis co-users (n = 35), and alcohol, tobacco, and cannabis tri-users (n = 42). All participants completed a structural MRI scan. Voxel-based morphometry was conducted to evaluate the effect of co-use on gray matter volume, with alcohol only users as the reference group. Age, sex, and scanner were included as covariates.

RESULTS

Alcohol and tobacco co-users had significantly decreased left orbitofrontal gray matter volume relative to alcohol only users (Cohen's d = .79). There were no differences in gray matter volume between the alcohol only and alcohol and cannabis co-users, or between the alcohol only and tri-user groups.

CONCLUSION

The additive effect of tobacco co-use on gray matter volumes in heavy drinkers was limited and localized. The effect of tri-use of alcohol, tobacco, and cannabis may have interacted, such that overlapping cannabis and tobacco use masked volume differences present in separate co-using groups. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Drinking less on cannabis use days: The moderating role of UPPS-P impulsive personality traits

Objective: Several studies suggest that alcohol and cannabis co-users are heavier drinkers and experience more alcohol-related consequences. However, day-level associations between co-use and drinking levels are mixed. One reason may be that individual characteristics moderate the daily impact of using alcohol alone or in conjunction with cannabis. The theory would suggest that highly impulsive individuals may drink more on co-use days, yet this assertion remains untested. Therefore, the current study tested whether impulsivity moderated the effect of co-use on same-day drinking quantity within veterans, a high-risk sample for substance use and impulsivity. Method: In a longitudinal observational study, co-using veterans (N = 139) completed three semi-annual assessments reporting on their daily drinking quantity and cannabis use via Timeline Followback (Observations = 19,245) and impulsivity via the UPPS-P. Mixed effect modeling was used to test hypotheses that co-use (compared to alcohol-only) days would be associated with heavier drinking for those high (but not low) in positive and negative urgency. Results: Significant interactions were found for positive urgency (PU) and lack of perseverance (LP), such that individuals at mean and low levels of PU and LP drank less on co-use (compared to alcohol-only) days. There were no significant interactions for other UPPS-P impulsivity facets. Conclusion: Findings are consistent with a substitution/compensatory effect for individuals at mean and low levels of both UPPS-P facets, and may be a byproduct of frequent cannabis use in veterans. In contrast, findings suggest that co-use and alcohol-only days may be characterized by similarly high levels of drinking for highly impulsive individuals. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Effects of cannabis use on alcohol consumption in a sample of treatment-engaged heavy drinkers in Colorado

BACKGROUND AND AIMS

Cannabis is commonly used among people who drink alcohol, but evidence suggests a nuanced relationship between alcohol consumption and cannabis use. In particular, among individuals undergoing alcohol treatment the impact of cannabis on alcohol intake may depend upon cannabis use frequency. We aimed to test the effects of within-day cannabis use on total drinks consumed and likelihood of binge drinking on a given day among all participants and compare these relationships between males and females and between individuals who reported infrequent and frequent cannabis use.

DESIGN

This observational study is a substudy of a larger randomized controlled trial (RCT). Individuals were included from the RCT if they reported any cannabis use and were divided into groups based on cannabis use patterns. Alcohol use was compared within and between groups.

SETTING

Individuals were recruited from 2016 to 2020 from community and university settings in Denver and Boulder, CO, USA.

PARTICIPANTS

Of the 182 individuals enrolled in the RCT, 96 cannabis-using subjects were included in these analyses.

MEASUREMENTS

Subjects completed a time-line follow-back (TLFB) at baseline, 4, 8 (end of treatment) and 20 weeks. Daily data on alcohol and cannabis use from the TLFB at all time-points were analyzed.

FINDINGS

Across the sample (n = 96), individuals drank approximately 29% fewer drinks [95% confidence interval (CI) = 18-39%, P < 0.001] and were 2.06 times (95% CI =1.37-3.08, P < 0.001) less likely to have a binge-drinking episode on days that cannabis was used compared with days that cannabis was not used. These patterns were observed in males, females and the infrequent and frequent cannabis use groups. Findings were inconclusive regarding differences in the association between cannabis use and alcohol outcomes when comparing males and females and when comparing infrequent and frequent cannabis use groups.

CONCLUSIONS

Heavy drinkers engaged in treatment to reduce their alcohol consumption who also use cannabis appear to increase their cannabis use on days when they reduce their alcohol consumption.

Co-use of Tobacco Products and Cannabis among Veterans: A Preliminary Investigation of Prevalence and Associations with Mental Health Outcomes

While tobacco product (such as combustible cigarettes and nicotine vaping products) and cannabis use rates remain high in the general United States (U.S.) population, veterans from the conflicts in Iraq and Afghanistan (i.e., OEF/OIF veterans) are at high risk of high rates of cannabis and tobacco use. Co-use of tobacco and cannabis (i.e., using both substances within a specified period of time or combining the drugs within the same device for use) is of growing prevalence in the U.S. However, little is understood about the prevalence rates of tobacco and cannabis co-use among U.S. veterans and its associations with mental health symptomatology. The current study conducted a preliminary analysis of co-use patterns of tobacco and cannabis and associated mental health outcomes among a sample of OEF/OIF veterans (N = 1,230). Results indicated high rates of lifetime and past 30-day use of both substances. Past 30-day co-users endorsed significantly higher levels of stress, PTSD, depression, and anxiety compared to singular product users. Results suggest that the addition of cannabis use in conjunction with tobacco use may be associated with greater mental health symptoms among veterans. Findings indicate veteran tobacco and cannabis co-users may benefit from mental health care to help mitigate poor mental health symptoms.

Patterns of same-day alcohol and cannabis use in adolescents and young adults with risky alcohol use

Same-day alcohol and cannabis use is relatively common in adolescents and young adults, constituting a higher-risk behavior relative to single-substance use. However, the association between quantity of alcohol and cannabis use on co-use days is understudied. We examined the association between the quantity of alcohol and same-day cannabis use with a multilevel regression analysis in a sample of youth (16-24 years old) with risky alcohol use. Participants reported one or more days of alcohol and cannabis over the past month (N = 468). Quantity of cannabis use was highest on heavy drinking days [M = 0.91 grams, SD = 0.68] followed by moderate drinking days (M = 0.78 grams, SD = 0.63), and lowest on days without alcohol use (M = 0.74 grams, SD = 0.64, p < 0.001). In multilevel modeling analyses, adjusted for clustering within individuals, greater quantity of drinking on a given day was associated with greater cannabis use (estimate = 0.03, p < 0.001). When using alcohol and cannabis on the same day, greater alcohol use was associated with greater cannabis use. Preventing days of heavy use of multiple substances, particularly among at-risk drinkers, may complement interventions addressing co-use generally to prevent substance-related consequences.

Early and Late Adolescent Factors that Predict Co-use of Cannabis with Alcohol and Tobacco in Young Adulthood

The changing legal landscape of cannabis in the USA has coincided with changes in how cannabis is used, including its co-use with other substances. This study analyzed 10 years of data from a diverse cohort of youth (N = 2429; 54% Hispanic, 16% Asian, 16% white, 3% black, 10% multiracial) to examine predictors in early and late adolescence of co-use of alcohol with cannabis (AC) and tobacco with cannabis (TC) at age 21. Two forms of co-use were examined: concurrent (use of both substances in past month) and sequential (use of one substance right after the other). Analyses focused on four predictor domains: individual (e.g., resistance self-efficacy), peer (e.g., time spent around peers who use), family (e.g., sibling use), and neighborhood (i.e., perceived alcohol and drug problems in neighborhood). For each co-use combination (AC or TC), we estimated parallel process piecewise latent growth models in a structural equation modeling framework using Mplus v8. The final AC and TC co-use models included all predictor variables from the four domains. Increases in positive expectancies and time spent around peers who use AC, as well as steeper decreases in resistance self-efficacy, were all related to a greater likelihood of AC co-use in young adulthood. Increases in sibling TC use and time spent around peers who use TC, as well as steeper decreases in resistance self-efficacy, were all related to a greater likelihood of TC co-use in young adulthood. Overall, findings highlight the importance of addressing peer influence in prevention programming during both early and late adolescence.

Cannabis use among military veterans: A great deal to gain or lose?

Policy changes have resulted in dramatic increases in access to cannabis for medical purposes. Veterans are disproportionately affected by conditions for which medical cannabis is often pursued, making an evidence-based perspective on risks versus benefits of high priority. The current review sought to examine the state of the evidence on the correlates and consequences of cannabis use among veterans. Using a comprehensive search strategy, 501 articles were identified and 86 studies met criteria for inclusion. The literature was predominated by cross-sectional studies (67%) of male veterans (71.4%-100% male) from the United States (93.0%). Three overarching themes emerged, comprising cannabis associations with other substance use, mental health, and physical health outcomes. The balance of the evidence associated cannabis use with negative health outcomes, with consistent positive associations with other substance use, psychiatric disorders, and self-harm/suicidality. Few studies examined the therapeutic effects of cannabis, thus limiting the potential to evaluate evidence of efficacy. Priority areas for future research are studies using designs that can examine the directionality of links between cannabis and health in veterans more conclusively, and studies directly examining therapeutic efficacy of cannabis-based therapies in veterans. Methodologically rigorous design will be essential to inform clinical recommendations and practices guidelines in an era of burgeoning access to cannabis.

Comparative associations of problematic alcohol and cannabis use with suicidal behavior in U.S. military veterans: A population-based study

Alcohol use disorder (AUD) and cannabis use disorder (CUD) are each associated with increased suicidal behavior, but it is unclear how their comorbidity relates to suicide risk. Understanding these associations in U.S. military veterans is especially important, given their heightened risk for suicide, high prevalence of AUD, and increasing access to cannabis. We compared associations of probable AUD, CUD, and AUD/CUD with suicide ideation, plan(s), and attempt(s) in a nationally representative sample of 4,069 veterans surveyed in 2019-2020 as part of the National Health and Resilience in Veterans Study. Among veterans who screened positive for current AUD, 8.7% also screened positive for current CUD. Among veterans who screened positive for current CUD, 33.3% screened positive for current AUD. Current and lifetime positive screens for AUD, CUD, and AUD/CUD were each strongly and independently associated with past-year suicide ideation and lifetime suicide ideation, plan(s), and attempt(s) [odds ratios (ORs) = 1.6-8.7]. Relative to veterans who screened positive for AUD only, veterans who screened positive for AUD/CUD and CUD only had higher odds of past-year suicide ideation (AUD/CUD: OR = 3.3; CUD only: OR = 2.4), lifetime suicide ideation (AUD/CUD: OR = 1.9; CUD only: OR = 2.6) and lifetime suicide plan(s) (AUD/CUD: OR = 1.7; CUD only: OR = 6.1). Collectively, findings suggest that screening positive for CUD might be an especially strong indicator of suicide ideation and planning in veterans with and without AUD, independent of sociodemographic, military, trauma, and other psychiatric factors. These findings underscore the importance of routine screening for CUD in suicide prevention efforts, especially as cannabis becomes more widely available.

Drug addiction co-morbidity with alcohol: Neurobiological insights

Addiction is a chronic disorder that consists of a three-stage cycle of binge/intoxication, withdrawal/negative affect, and preoccupation/anticipation. These stages involve, respectively, neuroadaptations in brain circuits involved in incentive salience and habit formation, stress surfeit and reward deficit, and executive function. Much research on addiction focuses on the neurobiology underlying single drug use. However, alcohol use disorder (AUD) can be co-morbid with substance use disorder (SUD), called dual dependence. The limited epidemiological data on dual dependence indicates that there is a large population of individuals suffering from addiction who are dependent on more than one drug and/or alcohol, yet dual dependence remains understudied in addiction research. Here, we review neurobiological data on neurotransmitter and neuropeptide systems that are known to contribute to addiction pathology and how the involvement of these systems is consistent or divergent across drug classes. In particular, we highlight the dopamine, opioid, corticotropin-releasing factor, norepinephrine, hypocretin/orexin, glucocorticoid, neuroimmune signaling, endocannabinoid, glutamate, and GABA systems. We also discuss the limited research on these systems in dual dependence. Collectively, these studies demonstrate that the use of multiple drugs can produce neuroadaptations that are distinct from single drug use. Further investigation into the neurobiology of dual dependence is necessary to develop effective treatments for addiction to multiple drugs.

Should You Recommend Cannabinoids for This Patient With Painful Neuropathy? : Grand Rounds Discussion From Beth Israel Deaconess Medical Center

Cannabis includes 140 active cannabinoid compounds, the most important of which are tetrahydrocannabinol and cannabidiol (CBD). Tetrahydrocannabinol is primarily responsible for the intoxicating effects of cannabis; CBD has potential therapeutic effects, including reduction in chronic pain. Recent legislative changes have resulted in the legal availability of cannabinoids in all 50 states, as well as a marked increase in patients' interest in their use. Despite an abundance of data, albeit of varied quality, clinicians may feel poorly prepared to counsel patients seeking advice on the suitability of CBD products for various indications, particularly chronic neuropathic pain. In 2018, on the basis of a systematic review of the literature, a Canadian Evidence Review Group published a guideline with recommendations for clinicians on prescribing cannabinoids in primary care practice. The overall quality of evidence was low to very low. In a meta-analysis of 15 randomized trials of medical cannabis for treating chronic pain, 39% of patients achieved at least a 30% reduction in pain. The corresponding value for placebo-treated patients was 30%; the number needed to treat was 11. More evidence exists for neuropathic pain than for other types of noncancer pain. Here, a general internist with a focus on addiction medicine and an addiction psychiatrist discuss how they would apply the literature to make recommendations for a patient with painful diabetic neuropathy, including counseling on both potential benefits and harms.

Ordering in alcohol and cannabis co-use: Impact on daily consumption and consequences

BACKGROUND

Co-use of alcohol and cannabis is highly prevalent among young adults and college students. Between-person reports suggest that co-use is associated with the experience of more frequent consumption and related consequences, compared to single substance use. However, recent studies have found conflicting evidence regarding the impact of co-use use on consumption and consequences in daily or event-level investigations. Conflicting evidence may be due to understudied factors, such as the order in which alcohol and cannabis are used. The current study aimed to examine the effect of substance use order on a) alcohol consumption; b) cannabis consumption; and c) negative alcohol and cannabis consequences.

METHODS

Data were collected from U.S. undergraduate college student alcohol and cannabis users (N = 258) who completed two 28-day longitudinal online assessment bursts examining alcohol and cannabis co-use patterns. Data were collected five times per day during both bursts (three months apart).

RESULTS

Controlling for between-person alcohol and cannabis use, within-person mixed-effects models indicated that using cannabis first within a co-use day was associated with lower daily alcohol consumption, but greater daily cannabis consumption. Substance use ordering was not linked to consequences, whereas between-person levels of alcohol consumption and within-person number of drinks in a day were positive predictors of consequences.

CONCLUSIONS

Overall, results highlighted that order of substance use is a robust predictor of consumption on co-use days. Therefore, future research on co-use use should consider patterns of use in addition to level of use.

Burden of cannabis use and disorder in the U.S. veteran population: Psychiatric comorbidity, suicidality, and service utilization

BACKGROUND

Cannabis use is associated with psychiatric illness and suicidality, which are prevalent among U.S. military veterans. However, the psychiatric burden of cannabis use and cannabis use disorder (CUD) among veterans is unclear. Using data from a nationally representative sample of veterans, we evaluated associations of lifetime cannabis use and CUD with psychiatric problems, suicidality, and treatment utilization.

METHODS

Participants were 3,157 veterans aged 21 to 96 years from the National Health and Resilience in Veterans Study (NHRVS). Cannabis use and CUD were assessed using the Mini International Neuropsychiatric Interview. Psychiatric morbidities, suicidal ideation and attempts, and treatment utilization were assessed and compared between three cannabis groups: [1] no lifetime cannabis use (never-use); [2] lifetime cannabis use but never met criteria for CUD (non-CUD cannabis use); [3] lifetime CUD (CUD).

RESULTS

Relative to the never-use group, veterans who used cannabis had elevated odds of current and lifetime posttraumatic stress disorder (PTSD), mood, anxiety, and substance use disorders, current suicidal ideation, lifetime suicide attempts, and current and lifetime mental health treatment utilization [odds ratios (ORs)=1.5-8.3]. Veterans with CUD had higher odds of current and lifetime PTSD, mood, and anxiety disorders, lifetime nicotine and alcohol dependence, and current suicidal ideation, relative to veterans who used cannabis but never met criteria for CUD (ORs=1.6-2.7).

LIMITATIONS

The cross-sectional design of this study precludes causal inference.

CONCLUSIONS

Cannabis use and CUD are associated with substantial psychiatric and suicide-related burden among veterans, highlighting the need for screening, education, and treatment to mitigate potential cannabis-related harm.

Does the Combination Matter? Examining the Influence of Alcohol and Cannabis Product Combinations on Simultaneous Use and Consequences in Daily Life

BACKGROUND

Alcohol and marijuana/cannabis are frequently used simultaneously (i.e., SAM use). SAM use is complex, and the ways in which alcohol and cannabis are simultaneously used may reveal differential effects. The purpose of this study was to examine day-level effects of distinct alcohol and cannabis product combinations on simultaneous use and consequences on that day.

METHODS

College student SAM users (N = 274; 50% women; Mage  = 19.82 years) were recruited to complete 54 days of data collection, including 5 repeated daily surveys each day. We identified 12 distinct product combinations reported during SAM-use days. We tested 4 reference groups, with one reflecting the most common use pattern and 3 potentially risky use patterns. We considered 3 outcomes (negative consequences, number of drinks, and number of cannabis uses) and used generalized linear mixed-effects models disentangling within- from between-person effects in all analyses.

RESULTS

Using multiple products (≥2) of alcohol was consistently linked to higher odds of experiencing a negative consequence. Combining beer with only one cannabis product (leaf or concentrate) was consistently associated with lower odds of a consequence. Combining cannabis with multiple alcohol products was associated with heavier alcohol consumption. Using dual cannabis products also was associated with heavier cannabis consumption, but this pattern was not significantly different than using concentrate only on a given day.

CONCLUSION

This is the first study to examine day-level influences of distinct alcohol and cannabis product combinations on consumption and consequences among young adult SAM users. Findings suggest that mixing alcohol products confers greater risk for negative consequences and heavier consumption, whereas there is little difference in cannabis consumption when using concentrate only vs. 2 cannabis products on a given day, except for concentrate + beer. Our findings support existing protective strategies of not mixing alcohol products and avoiding use of cannabis concentrate for SAM use as well.

Motives for Alcohol and Marijuana Use as Predictors of Use and Problem Use Among Young Adult College Students

This study examined (a) differences between alcohol-only users and alcohol-marijuana co-users and (b) motives for use in relation to alcohol and marijuana use and problem use. Spring 2016 data among 1,870 past 4-month alcohol users (63.6% female, 69.1% White) from seven Georgia colleges/universities were analyzed cross-sectionally and with regard to problem use measured 4 months later. Correlates of co-use (n = 345; vs. alcohol-only use, n = 1,525) included greater alcohol and marijuana use frequency, problem drinking and marijuana use, and alcohol use motives (p's < .05). Controlling for covariates, alcohol use frequency correlated with greater marijuana use frequency and Coping and Self-enhancement alcohol use motives, but lower Conformity alcohol use motives (p's < .001); greater Coping and Self-enhancement alcohol use motives (p's < .01) predicted problem alcohol use. Marijuana use frequency correlated with greater Coping and Expansion marijuana use motives (p's < .05); greater Expansion marijuana use motives (p = .005) predicted problem marijuana use. College-based substance use interventions should target Coping and Self-enhancement alcohol use motives and Expansion marijuana use motives.