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

Within-episode relations among simultaneous alcohol and cannabis use and continued drinking: The role of momentary subjective responses, craving, and drinking context

BACKGROUND

Simultaneous alcohol and cannabis use is associated with riskier daily drinking. However, little research has tested momentary mechanisms through which simultaneous use predicts continued drinking during acute drinking episodes. The current study tested whether simultaneous use moments predicted within-episode increases in subjective responses, craving, and continued drinking, and whether these relations were potentiated in social versus solitary settings.

METHODS

Emerging adults who co-use alcohol and cannabis (N = 85) completed 21 days of ecological momentary assessment with event-contingent reports during drinking episodes. Three-level multilevel models tested whether simultaneous (vs. alcohol-only) use moments indirectly predicted subsequent, continued drinking through subjective responses (i.e., high-arousal positive/stimulant, high-arousal negative/aggression, low-arousal positive/relaxation, low-arousal negative/impairment) and alcohol craving, and whether relations differed by social versus solitary contexts.

RESULTS

Within drinking episodes, simultaneous (vs. alcohol-only) use moments were associated with increased stimulation, which was indirectly associated with continued drinking through increased alcohol craving. Additionally, the relation between simultaneous (vs. alcohol-only) use and stimulating effects was potentiated during solitary drinking moments, whereas the relation between stimulating effects and craving was potentiated during social drinking moments. However, stimulating effects were higher in social contexts across all moments. Finally, simultaneous (vs. alcohol-only) use moments were associated with increased relaxation, which was indirectly associated with a lower likelihood of continued drinking through lesser craving.

CONCLUSIONS

Simultaneous use predicted both continued within-episode drinking and cessation of drinking, with acute subjective effects and craving as mechanisms, dependent upon context. Just-in-time interventions should consider targeting affect, craving, and context in event-specific interventions.

Interactive effects of alcohol and cannabis quantities in the prediction of same-day negative consequences among young adults

BACKGROUND

Simultaneous alcohol and cannabis use is common, but observational studies examining negative consequences of simultaneous use have rarely considered dose-related interactions between alcohol and cannabis. This study examined interactions between quantities of cannabis and alcohol consumed in predicting negative consequences on simultaneous use days.

METHODS

Young adults (N = 151; 64% female; 62% White) reporting recent simultaneous use and at least weekly alcohol and cannabis use completed 21 daily, smartphone-based surveys assessing previous day quantities of cannabis and alcohol used, types of cannabis used (flower, concentrates, edibles), and negative substance-related consequences. Multilevel models examined: (1) whether negative consequences differed within-person across simultaneous use days and single-substance use days; and (2) whether quantities of alcohol and cannabis consumed on simultaneous use days interacted, within-person, to predict negative consequences. We focused on quantities of cannabis flower (grams) in primary analyses and explored quantities of other forms of cannabis (concentrates, edibles) in supplementary analyses.

RESULTS

Participants reported fewer negative consequences on alcohol-only (243 observations) and cannabis-only (713 observations) days than they did on simultaneous use days (429 observations). On simultaneous use days involving cannabis flower use (313 observations across 81 participants), the within-person association between number of standard drinks and negative consequences was weaker on days during which larger (vs. smaller) amounts of cannabis flower were consumed. Inspection of simple slopes revealed that decreased alcohol use was associated with less of a decline in negative consequences when combined with relatively greater amounts of cannabis flower.

CONCLUSIONS

Although simultaneous use was associated with more negative consequences than alcohol-only and cannabis-only use, negative consequences on simultaneous use days varied as a function of the interaction between alcohol and cannabis quantities. As findings suggest that using larger amounts of cannabis may attenuate declines in negative consequences associated with lighter drinking, interventions for higher-risk simultaneous use patterns may benefit from a focus on quantities of both alcohol and cannabis.

Independent and concurrent cannabis use with alcohol, cigarettes, and other substances among college students: Rates and consequences

Objective: The purpose of this study was to examine patterns of concurrent cannabis and other substance use and their differential associations with cannabis-related problems and academic outcomes in college students. Participants: Participants were undergraduate students (N = 263; M age = 19.1 years; 61.2% female) who were eligible if they used cannabis at least 3 days in the past month (M = 10.1 days). Method: Substance use, academic-related outcomes, and measures of Cannabis Use Disorder (CUD) severity and problems were obtained in an online survey. Results: The five groups evaluated were cannabis-only users (5.3%), cannabis and alcohol (47.1%), cannabis, alcohol and cigarettes (16.7%), cannabis, alcohol and other substances (14.8%), or all-substances (16%). Cannabis-only and all-substance users reported using cannabis most frequently (ps ≤ .034), but only the latter reported greater CUD severity, problems, and poorer academic outcomes. Discussion: College student polysubstance users may be at increased risk for poorer outcomes compared to cannabis-only users and other groups.

Sequencing hour-level temporal patterns of polysubstance use among persons who use cocaine, alcohol, and cannabis: A back-translational approach

BACKGROUND

Polysubstance use is highly prevalent among persons who use cocaine; however, little is known about how alcohol and cannabis are used with cocaine. We identified temporal patterns of cocaine+alcohol and cocaine+cannabis polysubstance use to inform more translationally relevant preclinical models.

METHODS

Participants who used cocaine plus alcohol and/or cannabis at least once in the past 30 days (n=148) were interviewed using the computerized Substance Abuse Module and the newer Polysubstance Use-Temporal Patterns Section. For each day in the past 30 days, participants reported whether they had used cocaine, alcohol, and cannabis; if any combinations of use were endorsed, participants described detailed hourly use of each substance on the most "typical day" for the combination. Sequence analysis and hierarchical clustering were applied to identify patterns of timing of drug intake on typical days of cocaine polysubstance use.

RESULTS

We identified five temporal patterns among the 180 sequences of reported cocaine polysubstance use: 1) limited cocaine/cocaine+alcohol use (53%); 2) extensive cannabis then cocaine+alcohol+cannabis use (22%); 3) limited alcohol/cannabis then cocaine+alcohol use (13%); 4) extensive cocaine+cannabis then cocaine+alcohol+cannabis use (4%); and 5) extensive cocaine then cocaine+alcohol use (8%). While drug intake patterns differed, prevalence of use disorders did not.

CONCLUSIONS

Patterns were characterized by cocaine, alcohol, and cannabis polysubstance use and by the timing, order, duration, and quantity of episode-level substance use. The identification of real-world patterns of cocaine polysubstance use represents an important step toward developing laboratory models that accurately reflect human behavior.

Do Subjective Effects from Alcohol and Cannabis Predict Simultaneous Use During a Decision-Making Task?

Background: Simultaneous alcohol and cannabis use is associated with negative outcomes, yet little is known about what motivates the decision of simultaneous use. One possibility is that early-episode subjective effects motivate simultaneous use to complement or replace the first substance's effects. The current study used a hypothetical decision-making task to test this hypothesis. Objectives: College students (N = 486) were presented eight scenarios characterized by alcohol/cannabis subjective effects (i.e., high/low arousal positive [e.g., excited, relaxed], high/low arousal negative [e.g., aggressive, dizzy]) and asked their likelihood of simultaneously using the other substance per scenario. Multilevel modeling tested whether subjective effect scenarios predicted a higher likelihood of simultaneous use and whether ordering moderated this association. Results: Task-based simultaneous use likelihood was associated with self-reported simultaneous use, showing task validity. Scenarios characterized by high/low arousal positive effects were associated with higher likelihood of simultaneous use, whereas high/low arousal negative scenarios were associated with lower likelihood. Alcohol vs. cannabis-first scenarios were associated with higher likelihood of simultaneous use, and significant interactions were observed for high/low arousal positive and high arousal negative effects. High arousal positive scenarios were associated with higher likelihood of simultaneous use when cannabis was used first, low arousal positive scenarios with higher likelihood when alcohol was used first, and high arousal negative scenarios with lower likelihood when cannabis was used first. Conclusions: Beginning-of-episode subjective substance effects may be a promising event-level predictor of simultaneous use, and just-in-time interventions may benefit from targeting the ordering and subjective experiences of alcohol and cannabis use.

Doomscrolling: Prospective associations between daily COVID news exposure, internalizing symptoms, and substance use among sexual and gender minority individuals assigned female at birth

Cross-sectional studies have demonstrated associations between COVID news exposure, anxiety, and depression. However, longitudinal research examining the directionality of these associations is extremely limited. Further, most studies have focused on the general population and neglected sexual and gender minority individuals (SGM), a population disproportionately impacted by the pandemic. To address these limitations, the current study utilized data from a 30-day diary study of SGM assigned female at birth (N = 429). We examined concurrent and prospective associations between COVID news exposure, depressed and anxious affect, COVID distress, substance use, and motives for use. Further, we examined associations between cumulative COVID news exposure across the diary period and prospective changes in anxiety, depression, and COVID distress. When participants were exposed to more COVID news, they experienced more depressed and anxious affect, more COVID distress, less positive affect, and were more likely to use alcohol and cannabis to cope. Further, when participants were exposed to more COVID news, they experienced subsequent increases in depressed affect, decreases in positive affect, and increases in the likelihood of using cannabis to cope. Findings also provided evidence of bi-directional prospective associations between COVID news exposure and COVID distress and of a cumulative impact of COVID news exposure on anxiety, depression, and COVID distress. Findings suggest that individuals should balance the need to remain informed about the pandemic and their own mental health when considering how much COVID news to consume.

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.

Simultaneous Cannabis and Alcohol Use among Medical Cannabis Patients

Background: During the past two decades of cannabis legalization, the prevalence of medical cannabis (MC) use has increased and there has also been an upward trend in alcohol consumption. As less restricted cannabis laws generate more adult cannabis users, there is concern that more individuals may be simultaneously using medical cannabis with alcohol. A few studies have examined simultaneous use of medical cannabis with alcohol, but none of those studies also assessed patients' current or previous non-medical cannabis use. This paper explores simultaneous alcohol and medical cannabis use among medical cannabis patients with a specific focus on previous history of cannabis use and current non-medical cannabis use. Methods: A retrospective cohort study of MC patients (N = 319) from four dispensaries located in New York. Bivariate chi-square tests and multivariable logistic regression are used to estimate the extent to which sociodemographic and other factors were associated with simultaneous use. Results: Approximately 29% of the sample engaged in simultaneous use and a large share of these users report previous (44%) or current (66%) use of cannabis for non-medical purposes. MC patients who either previously or currently use cannabis non-medicinally, men, and patients using MC to treat a pain-related condition, were significantly more likely to report simultaneous alcohol/MC use. Conclusions: Findings indicate that there may be differential risks related to alcohol/MC use, which should be considered by cannabis regulatory policies and prevention/treatment programs. If patients are using cannabis and/or alcohol to manage pain, clinicians should screen for both alcohol and cannabis use risk factors.

Alcohol First, Cannabis Last: Identification of an Especially Risky Use Pattern among Individuals Who Co-Use Alcohol and Cannabis

Background: Alcohol and cannabis co-use is common and confers increased risk for potential harms, such as negative consequences and substance dependence. The existing evidence suggests that factors such as dose of delta-9-tetrahydrocannabinol (THC) consumed and order of use of each substance (i.e., using alcohol or cannabis first or last when co-using) may impact co-use outcomes. Existing co-use research has focused primarily on college-samples or young adults, and few studies have explored these nuanced relations among community samples. Methods: We examined survey data from 87 community members (mean age 32.9 years, 49.4% female) recruited from legal market cannabis dispensaries. Using a combination of regression techniques (i.e., OLS, negative binomial, censor-inflated) we modeled relations among co-use ordering patterns, THC dose and cannabis outcomes as well as interactions with sex assigned at birth and age. Results: Individuals who endorsed co-use reported significantly higher CUDIT scores than those who had never co-used (p < 0.01). Using alcohol first and cannabis last (a pattern we refer to as "AFCL") was more common among females than males (p < 0.01). In the context of typical substance use weeks, more frequently engaging in the AFCL pattern was associated with significantly higher CUDIT scores (p < 0.001) and negatively predicted positive consequences (p < 0.001). Other patterns predicted higher CUDIT scores during heavy use weeks. Conclusions: Results indicate that co-use ordering patterns are related to substance use outcomes. Further research leveraging within-subjects, longitudinal designs is needed to test causal relations between these variables.

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.

Dose-dependent Relationships of Same-day and Typical Substance Use to Sleep Duration in College Cannabis and Alcohol Users: A Multilevel Modeling Approach Using Daily Diary Data

This study characterized how quantities of cannabis and alcohol use affect sleep. Single-day and typical cannabis and alcohol use patterns were considered to assess acute-chronic use interactions. Linear and non-linear associations assessed dose-dependence. College students (n=337; 52% female) provided 11,417 days of data, with up to five time points per day. Daily self-reported sleep duration, cannabis use quantity, and alcohol use quantity were subjected to linear mixed modeling to capture linear and curvilinear associations between single-day and typical use on same-night and typical sleep. Sleep duration (difference between bedtime and waketime) was the outcome. Quantity of cannabis used each day andtypical quantity used across all days were predictors in the cannabis models. Parallel single-day and typical alcohol variables were predictors in the alcohol models. Follow-up analyses excluded days with alcohol-cannabis co-use. Main effects of single-day and typical cannabis quantity on sleep duration were observed when all cannabis-use days were modeled. Higher than typical doses of single-day and typical cannabis were associated with longer sleep durations, but only to a point; at the highest doses, cannabis shortened sleep. A main effect of single-day alcohol quantity and two interactions (single-day use with both linear and curvilinear typical use) on sleep duration were observed when all alcohol-use days were modeled. Greater alcohol consumption on a given day led to shorter same-night sleep, but typically heavier drinkers required higher doses than typically lighter drinkers to experience these adverse effects. Follow-up models suggested alcohol co-use may contribute to the purported sleep-promoting effects of cannabis.

A qualitative examination of positive and negative consequences young adults experience from simultaneous alcohol and cannabis use

OBJECTIVE

Alcohol and cannabis are two of the most commonly used substances among young adults, and most individuals who use both substances use them simultaneously, that is, on the same occasion such that their effects overlap. Given the high prevalence of simultaneous alcohol and cannabis use, it is important to understand the relationship between simultaneous use and consequences. This study presents a qualitative examination of positive and negative consequences of simultaneous use.

METHOD

We conducted individual interviews among 36 young adults who engage in simultaneous use (23 women, 12 men, 1 trans man). Interviews included open-ended questions examining negative and positive consequences of simultaneous use and how simultaneous use differed from single substance use (alcohol only use, cannabis only use). Interviews were analyzed using applied thematic analysis.

RESULTS

Young adults reported numerous negative and positive consequences of simultaneous use, many overlapping with single substance use. Yet, they also reported unique combinations of positive consequences not experienced by single substance use. Young adults discussed patterns of use that were sometimes approached intentionally (e.g., quantity of substances used, order) that influenced consequences.

CONCLUSIONS

Together these findings provide further insight into young adults' simultaneous use experiences. Next steps should include quantitative exploratory research to identify and determine the frequency of specific consequences experienced during simultaneous use and examine the relationship between simultaneous use consequences and particular patterns of use. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Associations between alcohol and cannabis use order, frequency, quantity, and consequences in a college sample of individuals who co-use alcohol and cannabis

BACKGROUND AND OBJECTIVES

Using both alcohol and cannabis (either at the same time or at different times) is common among college students, and is called "co-use." Using these substances simultaneously, such that their effects overlap, is thought to be an especially risky co-use pattern. Gaining a better understanding of how co-use patterns relate to substance use and consequences could aid prevention and intervention efforts.

METHODS

We examined college students (N = 401) who reported using both alcohol and cannabis at least once in the past 30 days. Path analysis was used to explore relations among co-use patterns (number of days in a typical week that participants used both alcohol and cannabis; the number of days using alcohol first, cannabis first, alcohol last, and cannabis last; the number of days of simultaneous use), past-30-day alcohol and cannabis consequences, use frequency, and typical quantities used.

RESULTS

Each additional day of using alcohol first was associated with fewer past-30-day cannabis consequences. Each additional day of using cannabis first was associated with fewer alcohol-related consequences. Each additional day of using alcohol and cannabis on the same day and each additional day of simultaneous use were both associated with less cannabis used and alcohol consumed in a typical week.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

This study is among the first to identify associations between alcohol and cannabis order and outcomes (i.e., consequences and consumption). Results suggest that modifying which substance is used first on a given day could be a practical intervention strategy for individuals who co-use alcohol and cannabis.

Protocol for a mobile laboratory study of co-administration of cannabis concentrates with a standard alcohol dose in humans

Cannabis is commonly used among people who drink alcohol, yet evidence on acute effects of co-use is conflicting. Two important variables that may influence the effects of cannabis and alcohol are cannabinoid content (i.e., the ratio of cannabidiol [CBD] and 9-tetrahydrocannabinol [THC]) as well as the order of use (i.e., cannabis before alcohol vs. alcohol before cannabis). Research is mixed regarding the acute imapct of cannabis on alcohol consumption and intoxication, with some studies suggesting additive effects of alcohol and cannabis, and others demonstrating negligible effects of combining these substances. Further complicating this, high-THC-content cannabis concentrates are increasingly popular on the legal-market, but to our knowledge, no studies have explored concentrate and alcohol co-use. In addition to cannabinoid content, order of use may influence intoxication and other acute effects, but is also understudied. Co-use studies typically administer a fixed dose of alcohol before cannabis, and there is a lack of data on the acute effects of cannabis before alcohol. Thus, there is a need for experimental co-use studies exploring the impact of cannabinoid content (particularly of highly potent cannabis concentrates) and order effects on intoxication. This study uses a federally-compliant mobile laboratory procedure to explore the effects of co-administration of legal-market cannabis concentrates with a moderate alcohol dose (.8g/kg) in a sample of community participants who regularly use alcohol and cannabis. The study will also explore alcohol and cannabis order effects (cannabis before alcohol vs. alcohol before cannabis). Outcomes are objective intoxication (measured using blood cannabinoid level, heart rate, psychomotor performance and breath alcohol level [BrAC]) and subjective intoxication (assessed via self-report measures). Overall, this study may influence harm-reduction recommendations for individuals who drink alcohol and use cannabis.

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.

Understanding Heterogeneity Among Simultaneous Alcohol and Marijuana Users: Latent Classes Derived From Daily Diary Data

OBJECTIVE

Simultaneous use of alcohol and marijuana (SAM) is common among U.S. college students, but little research has examined specific substance use behaviors during SAM use episodes. This study identified latent classes of SAM users based on their SAM, alcohol-only, and marijuana-only use episodes.

METHOD

College student SAM users (N = 284; 50.7% female; M age = 19.8 years) completed up to five surveys each day across two 4-week bursts. Latent class analysis (LCA) was used to characterize SAM users based on seven latent class indicators of use behavior. Sex was examined in relation to latent class membership.

RESULTS

Five unique classes emerged: Frequent Marijuana-Focused SAM users (21%); Frequent Alcohol-Initiating SAM users (29%); Heavy-Drinking Infrequent SAM users (12%); Moderate SAM users (29%); and Light Infrequent SAM users (9%). These groups were differentiated primarily by their frequency of SAM use, form of marijuana, whether marijuana was used on non-SAM occasions, and whether consequences were experienced. Groups differed significantly by sex.

CONCLUSIONS

College student SAM users are heterogeneous with respect not only to their degree of SAM use but also in their pattern of drinking, type of marijuana use, relative focus on alcohol versus marijuana, and risk of experiencing acute negative consequences. Describing this heterogeneity is an important step toward developing interventions for different types of users.

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).

Understanding Heterogeneity Among Simultaneous Alcohol and Marijuana Users: Latent Classes Derived From Daily Diary Data

OBJECTIVE

Simultaneous use of alcohol and marijuana (SAM) is common among U.S. college students, but little research has examined specific substance use behaviors during SAM use episodes. This study identified latent classes of SAM users based on their SAM, alcohol-only, and marijuana-only use episodes.

METHOD

College student SAM users (N = 284; 50.7% female; M age = 19.8 years) completed up to five surveys each day across two 4-week bursts. Latent class analysis (LCA) was used to characterize SAM users based on seven latent class indicators of use behavior. Sex was examined in relation to latent class membership.

RESULTS

Five unique classes emerged: Frequent Marijuana-Focused SAM users (21%); Frequent Alcohol-Initiating SAM users (29%); Heavy-Drinking Infrequent SAM users (12%); Moderate SAM users (29%); and Light Infrequent SAM users (9%). These groups were differentiated primarily by their frequency of SAM use, form of marijuana, whether marijuana was used on non-SAM occasions, and whether consequences were experienced. Groups differed significantly by sex.

CONCLUSIONS

College student SAM users are heterogeneous with respect not only to their degree of SAM use but also in their pattern of drinking, type of marijuana use, relative focus on alcohol versus marijuana, and risk of experiencing acute negative consequences. Describing this heterogeneity is an important step toward developing interventions for different types of users.

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.

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.

Qualitative examination of simultaneous alcohol and cannabis use reasons, evaluations, and patterns among heavy drinking young adults

Use of alcohol and cannabis together so their effects overlap (simultaneous use) is common among college students and associated with numerous negative consequences. The aim of this study was to gain insight into college students' recent simultaneous use events in order to inform future studies (i.e., generate hypotheses, inform measures/assessments of simultaneous use, and identify factors influencing simultaneous use). Qualitative interviews of simultaneous use experiences among heavy drinking college students (n = 38) were conducted to better understand reasons for simultaneous use, evaluations of simultaneous use events, and patterns of substance use during simultaneous use events. Findings indicated that students' reasons for simultaneous use included traditional four-factor motive types (i.e., social, conformity, enhancement, and coping), cross-fading motives, harm reduction motives (e.g., to drink less), and reactive/situational reasons (e.g., because it was offered/available). There was variability in participants' subjective evaluations of how positive versus negative simultaneous use events were and how this compared to single-substance events. Evaluation of simultaneous use events depended on patterns of use, external and internal context, and consequences experienced. Additionally, patterns of simultaneous use including order of substances, timing of using each substance, and quantities of substances used were highly variable across participants. Notably, participants endorsed patterns of use they perceived to reduce negative consequences during simultaneous use events. Further research on reasons for simultaneous use and patterns of use may help identify simultaneous use occasions that result in greater risk; identification of high-risk simultaneous use occasions and evaluation of these occasions can then help inform targeted interventions. (PsycInfo Database Record (c) 2021 APA, all rights reserved).