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

Proximal antecedents and acute outcomes of simultaneous alcohol and cannabis use: Systematic review of daily- and event-level studies

Many studies have revealed that individuals who engage in simultaneous use of alcohol and cannabis report elevated substance-related consequences relative to those who use only alcohol or cannabis; however, evidence from emerging studies examining within-person differences across simultaneous use and single substance use occasions is less consistent. This systematic review aimed to synthesize findings from existing day- and event-level studies of within-person differences in the proximal antecedents and acute outcomes associated with simultaneous use versus single substance use episodes. Our search strategy revealed 30 eligible articles. Two categories of antecedents (i.e., internal [e.g., motives] and external [e.g., social context]) and three categories of outcomes (i.e., consumption behavior, general positive and negative consequences, and specific consequences) were identified. The current literature consistently suggests that greater day- or event-level social and enhancement motives, as well as being in a social context, predict greater likelihood of engaging in simultaneous use compared with alcohol- or cannabis-only use. However, there was heterogeneity in findings regarding the role of other person-level antecedents. Further, while most evidence pointed to heavier alcohol consumption on simultaneous use occasions versus alcohol-only occasions, findings for elevations in acute negative and positive substance-related consequences on simultaneous use versus single substance use occasions were mixed. Additionally, four studies found that increased consequences on simultaneous use occasions depended on the level of alcohol consumed. This review identifies several antecedents for simultaneous use events but suggests that simultaneous use occasions are not always associated with more acute harms than single substance use occasions. Given the extent to which the current literature is mixed, this review emphasizes the importance of methodological improvements and future research examining the mechanisms linking simultaneous use with substance-related consequences to help reconcile findings across within-person and between-person studies.

Mental Health and Dispositional Predictors of Simultaneous Versus Concurrent Cannabis and Alcohol Use in a Canadian Context

Objective

Cannabis has become more available in Canada since its legalization in 2018. Many individuals who use cannabis also use alcohol (co-use), which can be used either at the same time such that their effects overlap (simultaneous use) or at different times (concurrent use). Though studies have identified predictors of co-use relative to single-substance use, less is known about the predictors of specific types of co-use. The present study examined the mental health and dispositional predictors of simultaneous relative to concurrent use of the two legal substances (cannabis and alcohol) among adults in Canada.

Method

Canadian adults reporting past-year use of both cannabis and alcohol (N = 1,761) were recruited from Academic Prolific and six Canadian universities. Participants completed online self-report measures of demographic characteristics, cannabis and alcohol co-use, mental health symptoms, impulsivity, and personality traits.

Results

Binary logistic regression analyses revealed that when independent variables were each examined individually, greater severity of depression, anxiety, PTSD, and ADHD symptoms; greater negative urgency and lack of premeditation; and greater impulsivity each predicted an increased likelihood of reporting past-year simultaneous use relative to concurrent use. When independent variables were grouped into three separate models (mental health, impulsivity, and personality variables), greater anxiety symptom severity, ADHD symptom severity, negative urgency, and sensation seeking were each uniquely associated with an increased likelihood of simultaneous relative to concurrent use.

Conclusions

Individuals with elevated anxiety and ADHD symptoms, as well as negative urgency and sensation seeking, may be more inclined to engage in simultaneous use to self-medicate and achieve greater symptom reduction. Future studies may examine the directionality of these relations and motives (e.g., coping) that may differentiate simultaneous and concurrent use.

Short-term changes in social role statuses across young adulthood and their relation to heavy drinking in a given month

Young adulthood is a developmental period during which individuals experience shifts in their social roles in various domains, which coincides with a period of time that is also high risk for lifetime peaks in alcohol use. The current study examined age-related changes in heavy episodic drinking (HED) and high-intensity drinking (HID) and associations with short-term (i.e., monthly) variation in young adults' social roles over a 2.5-year period in a community sample of young adults who reported past-year alcohol use (N = 778, baseline age range 18-23). Results showed probabilities of past-month HED and HID changed in a nonlinear fashion across ages 18-26 with greater probabilities of use at younger ages. Most participants did not report being in the same social role status every sampled month, underscoring the presence of short-term role variation. Living with parents and being in a serious romantic relationship in a given month were negatively associated with past-month HED. Living with parents in a given month was also negatively associated with past-month HID. Being a 4-year college student and being employed full-time in a given month were not significantly related to either outcome. Findings provided partial evidence that monthly statuses were associated with heavy drinking. Several avenues for future research are described in light of the findings.

Alcohol and cannabis use in daily lives of college-attending young adults: Does co-use correspond to greater reported pleasure?

Co-use of alcohol and cannabis is prevalent and linked with heightened risk for substance-related harms. The current study investigated the role of substance-related pleasure as a reinforcing factor for co-use relative to alcohol or cannabis use. Specifically, we used data from a 21-day diary study of college students to examine day-level associations between co-use and self-reported substance-related pleasure (any, level of pleasure). Participants were 237 college students (65 % female sex at birth, ages 18-24) who reported 1+ alcohol and cannabis co-use occasion. Participants completed daily surveys across 21 consecutive days about yesterday's substance use and experiences of pleasure, yielding 2,086 daily surveys involving alcohol and/or cannabis use. Multilevel models indicated that odds of substance-related pleasure were higher on days with co-use relative to days with single-substance use, and level of pleasure was higher on co-use days relative to cannabis but not alcohol use days. Pleasure may serve as a reinforcing property of co-use that may be related to continued use despite experience of negative consequences. Intensity of pleasure related to co-use appears to be largely driven by use of alcohol. However, given mixed findings concerning level of pleasure, individuals may report co-use increases feelings of pleasure but do not actually experience more pleasure. Pleasure may serve as a viable target in future prevention and intervention programming targeting co-use.

Young adult impaired driving behaviors and perceived norms of driving under the influence of simultaneous alcohol and cannabis use

BACKGROUND

Impaired driving behaviors among young adults who are under the influence of simultaneous alcohol and marijuana/cannabis (SAM) use are associated with increased risks of motor vehicle accidents and resulting increased injury and mortality. Exploration of associations with descriptive and injunctive norms may have prevention implications.

METHODS

Young adults (aged 18-25; N = 1941) in the 2019 cohort of the Washington Young Adult Health Survey comprised study participants. Associations between descriptive norms (estimates of other's frequency of driving under the influence of SAM [DUI-SAM] and riding with a SAM impaired driver [RWI-SAM]), injunctive norms (perceived approval or disapproval of DUI-SAM and RWI-SAM for young adults in their community), and past month DUI and RWI behaviors were assessed with logistic regression models, adjusting for covariates and applying post-stratification weights.

RESULTS

DUI-SAM was reported by 2.7% and almost double (5.3%) reported RWI-SAM at least once in the past month. Almost half of the participants believed the average young adults in Washington State engaged in DUI-SAM (49.8%) and RWI-SAM (48.7%) at least once a month in the past year (i.e., descriptive norms). The majority reported DUI-SAM (68.8%) and RWI-SAM (67.6%) to be totally unacceptable for young adults in their community (i.e., injunctive norms). In models adjusting for covariates including SAM use frequency and corresponding injunctive norms, descriptive norms were not associated with DUI, but were positively associated with RWI-SAM. However, after controlling for SAM use frequency and descriptive norms, higher perceived approval (i.e., injunctive norms) was significantly associated with increased odds of all DUI and RWI behaviors.

CONCLUSIONS

Injunctive norms for SAM impaired driving behaviors may be a promising intervention focus for DUI and RWI behaviors. Future research is needed to replicate these findings to determine if development and evaluation of individual and community-based interventions focused on changing normative beliefs are warranted.

Exploring the substitution of cannabis for alcohol and other drugs among a large convenience sample of people who use cannabis

BACKGROUND

The substitution of cannabis for alcohol and other drugs has been conceptualised in a harm reduction framework as where cannabis is used to reduce the negative side-effects, addiction potential, and social stigma of other drugs. There is currently mixed evidence with recent reviews suggesting cannabis co-use patterns may vary by age and ethnicity. Yet few studies have had large enough samples to examine this demographic variation in detail.

AIMS

To explore the co-use of cannabis with alcohol and other drugs within demographic subgroups of a large sample of people who use cannabis. Specifically: (1) whether cannabis is being substituted for other drugs, and (2), whether cannabis use leads to more, less or the same level of other drug use.

METHOD

Online convenience survey promoted via Facebook™ completed by 23,500 New Zealand respondents. Those who had used cannabis and any of eight other substances in the same six-month period were asked if their use of cannabis had any impact on their use of each other substance ("a lot more", "little more", "no impact/same", "little less", "a lot less"). Frequency and quantity used of each other drug was compared by co-use group. Generalised logistic regression models were developed to predict co-use categories.

RESULTS

Significant proportions reported cannabis use led to "less" alcohol (60%), synthetic cannabinoid (60%), morphine (44%) and methamphetamine (40%) use. Those who reported using "less" had lower frequency and amount used of other drugs. Approximately seven-out-ten reported cannabis use had "no impact" on LSD, MDMA, and cocaine use. One-in-five reported using cannabis led to "more" tobacco use. Young adults (21-35-years) were more likely to report cannabis use led to "less" drinking and methamphetamine use. Adolescent co-users (16-20 years) reported mixed impacts. Māori were more likely to report cannabis use resulted in "less" alcohol, tobacco, methamphetamine, and LSD use. Students and those living in cities were less likely to report cannabis use lowering use of other substances.

CONCLUSION

Cannabis and other drug co-use patterns are moderated by life stages, lifestyles, cultural perspectives, and urbanicity. Harm reduction initiatives and policy reforms should take account of these moderating factors.

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.

Bidirectional associations between sleep and cannabis and alcohol (co-)use in daily life

BACKGROUND

Poor sleep is common in the context of cannabis use, but experimental and daily-life studies provide mixed evidence for whether cannabis use helps or disturbs same-night sleep. Despite a high prevalence of co-use of alcohol and cannabis, most studies of cannabis use and sleep do not consider alcohol use. We sought to add to this literature by examining associations between cannabis and sleep in the context of alcohol co-use and to examine these associations bidirectionally using ecological momentary assessment.

METHODS

Participants were 88 adults reporting cannabis use at least 3×/week and simultaneous alcohol and cannabis use at least 2×/week. For 14 days, participants completed morning surveys assessing hours slept and perceived sleep quality from the night before. In morning surveys, random surveys, and substance-specific surveys, participants also reported on alcohol and cannabis craving, use, and amounts.

RESULTS

Primary results from multilevel models demonstrated that cannabis use was not independently associated with sleep (duration or quality). However, cannabis use attenuated alcohol's negative effects on sleep quality.

CONCLUSIONS

Results question the utility of cannabis use to improve sleep but highlight the attenuated negative effects of alcohol as a potential reinforcer of alcohol-cannabis co-use. Future work should continue to consider polysubstance use and integrate additional self-report and objective measures of sleep health to further clarify how cannabis use affects sleep.

Secondhand Harms From Cannabis Use: Findings From Washington State, United States

OBJECTIVE

There are few studies on harms attributed to others' cannabis use. We assessed individual- and contextual-level correlates of secondhand harms from cannabis use and considered whether cannabis legalization support, along with cannabis user status, predicted such harms.

METHOD

Data were from five repeated cross-sectional, state-representative telephone surveys of Washington State residents ages 18 and older, years 2014-2016. For four surveys, outcome variables were past-12-month reports of experiencing any of five harms (family, traffic-related, vandalism, physical, or financial), and in 2016 only, three harm types separately: (a) harassment, (b) safety-related (traffic, vandalism, physical), and (c) family or financial, attributed to another's cannabis use. All models included a three-category typology comprising participants' own cannabis use and whether they supported cannabis use legalization (user supporter, nonuser nonsupporter, nonuser supporter). We estimated logistic regression models for the full sample and by gender, adjusting for individual- and Census tract-level covariates.

RESULTS

Compared with non-cannabis users supporting legalization, nonusers who did not support legalization reported significantly greater odds of perceiving secondhand cannabis harms. Cannabis users supporting legalization did not differ from nonuser supporters. Predictors of reported harms also differed by gender. Whereas current drinkers had lower odds of reporting any harm from others' cannabis use overall, heavy-drinking women but not men reported greater odds of any cannabis secondhand harm.

CONCLUSIONS

Augmenting research on individual harms associated with cannabis use by including secondhand impacts such as social and family problems, along with safety risks, provides a more comprehensive picture of the effects of cannabis use.

Examining the Impact of Simultaneous Alcohol and Cannabis Use on Alcohol Consumption and Consequences: Protocol for an Observational Ambulatory Assessment Study in Young Adults

BACKGROUND

There is significant conflicting evidence as to how using cannabis while drinking alcohol (ie, simultaneous alcohol and cannabis use) impacts alcohol volume consumed, patterns of drinking, and alcohol-related consequences. The impact of simultaneous use on drinking outcomes may be influenced by several within-person (eg, contextual) and between-person (individual) factors.

OBJECTIVE

This study was designed to examine naturalistic patterns of alcohol and cannabis use to understand how simultaneous use may impact drinking outcomes. The primary aims were to understand the following: (1) if simultaneous use is associated with increased alcohol consumption and riskier patterns of drinking, (2) if simultaneous use leads to increased alcohol consequences, and (3) how contextual circumstances moderate the impact of simultaneous use on consumption and consequences.

METHODS

Data collection involves a 28-day ambulatory assessment protocol in which a sample of non-treatment-seeking young adults who report simultaneous use of alcohol and cannabis complete ecological momentary assessments (random, event-contingent, and time-contingent surveys) of alcohol and cannabis use, contexts, motives, and consequences on their personal smartphones while continuously wearing an alcohol biosensor bracelet. Participants also complete a baseline assessment, brief internet-based check-in on day 14, and a final session on day 28. Community-based recruitment strategies (eg, social media and flyers) were used to enroll 95 participants to obtain a target sample of 80, accounting for attrition.

RESULTS

Recruitment and data collection began in May 2021 and continued through June 2024. Initial results for primary aims are expected in October 2024. As of March 2024, the project had recruited 118 eligible participants, of whom 94 (79.7%) completed the study, exceeding initial projections for the study time frame. Remaining recruitment will provide the capacity to probe cross-level interactions that were not initially statistically powered. Strengths of the project include rigorous data collection, good retention and compliance rates, faster-than-expected enrollment procedures, use of a novel alcohol biosensor, and successful adaptation of recruitment and data collection procedures during the COVID-19 pandemic.

CONCLUSIONS

This is the first investigation to assess the key momentary predictors and outcomes of simultaneous use as well as self-reported and objective (via alcohol biosensor) measures of alcohol consumption and patterns. The results of this study will inform prevention efforts and studies of individuals who use cannabis who are engaged in alcohol treatment.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/58685.

Behavioural patterns and dangers: a mixed-methods exploration of simultaneous polysubstance use and intervention strategies among Swiss adolescents

BACKGROUND

Recent trends in Switzerland indicate a concerning rise in simultaneous polysubstance use among adolescents, a practice marked by the concurrent or sequential consumption of multiple psychoactive substances, notably alcohol and cannabis, alongside prescription medications (e.g. benzodiazepines) and illicit drugs, resulting in dozens of fatal outcomes. However, data on simultaneous polysubstance use and evidence-based approaches to effective prevention is lacking.

AIMS OF THE STUDY

The study aimed to explore and gain insights into use patterns, use settings, use motives, harm-reduction strategies, concerns associated with substance use, and support and counselling services from the point of view of adolescents practicing simultaneous polysubstance use in Switzerland.

METHODS

An exploratory study was conducted via an online survey (n = 116) and two focus group discussions with affected Swiss adolescents aged 14 to 20. A mixed-methods approach was applied to gain insights and better understand the phenomenon of simultaneous polysubstance use among Swiss adolescents. Quantitative survey data obtained between November 2021 and March 2023 by means of convenience sampling - organised by distributing flyers (in three national languages) among several project partners, on the internet, over social media and by word of mouth - was analysed descriptively, whereas qualitative survey data and focus group data were thematically explored. A concurrent nested design was employed, utilising quantitative findings as a core foundation for addressing research questions, while qualitative findings were instrumental in validating and providing contextual depth to the results.

RESULTS

Our findings reveal a preference of the sample for combining alcohol with cannabis and/or other substances (e.g. benzodiazepines or hard drugs) in social settings, driven by diverse motives, including enhancement of experiences and partly maladaptive coping mechanisms leading to self-medication. Despite some awareness of the potential harms, there is a significant reliance on peer-shared strategies for harm reduction, highlighting a gap in formal support and counselling services, some of which are perceived by adolescents as lacking empathy and relevance.

CONCLUSIONS

This study underscores the urgency of developing targeted, youth-centred interventions that resonate with the lived realities of adolescents, aiming not only to reduce substance use but also to address the broader psychosocial factors contributing to simultaneous polysubstance use. By shedding light on the complex dynamics of adolescent polysubstance use, our research contributes to the ongoing dialogue on effective prevention strategies, advocating for a holistic approach encompassing education, policy reform and community support to tackle this multifaceted public health challenge.

Examining the Role of Alcohol and Cannabis Use Patterns in Bystander Opportunity and Behavior for Sexual and Relationship Aggression

OBJECTIVE

This study aimed to investigate the association between alcohol and cannabis use patterns and bystander intervention for sexual and relationship violence risk among college students who have used cannabis in the past year. The study tested two hypotheses: (1) Reports of bystander opportunities will differ based on participants' alcohol and cannabis use patterns, and (2) among those who report bystander opportunities, reports of bystander behaviors will differ based on their alcohol and cannabis use patterns.

METHOD

Participants were 870 students recruited from two large, minority-serving universities in the United States who reported past-year cannabis use. Participants reported their typical alcohol and cannabis use patterns and bystander opportunities and behaviors. Students were grouped for analysis based on their reported average substance use into four groups: alcohol and cannabis use on the same day, alcohol use only, cannabis use only, or no use.

RESULTS

Students who reported alcohol and cannabis use on the same day, compared with those who reported alcohol use only, reported more bystander opportunities and behaviors in situations at risk for sexual and relationship violence. Compared with alcohol use only, students who reported only using cannabis or no use reported fewer bystander opportunities and behavior related to keeping others safe in party settings.

CONCLUSIONS

Alcohol and cannabis use patterns are associated with bystander intervention, emphasizing the need to include knowledge about cannabis and co-use in bystander programming that aims to reduce sexual and relationship violence.

Order of Cannabis and Alcohol Use on Pregaming and Non-Pregaming Days Among College Students

OBJECTIVE

Pregaming is common among college students and is associated with heavy drinking and negative alcohol-related consequences. The use of cannabis on pregaming days may exacerbate negative alcohol-related consequences, and the ordering of when cannabis is used on these days may buffer against or intensify these consequences. Considering the growing rates of simultaneous use of cannabis and alcohol among college students, it is necessary to examine the role of pregaming behaviors in the context of cannabis use and its effects on alcohol-related consequences.

METHOD

In the present study, college students (N = 485) completed a baseline survey and 14 days of daily surveys, reporting on daily alcohol and cannabis use and alcohol-related negative consequences. Multilevel structural equation models were fit to evaluate cannabis outcomes on pregaming versus non-pregaming drinking days and ordering effects on alcohol-related consequences, controlling for number of drinks, age, and sex.

RESULTS

Across all drinking days, pregaming on that day as well as cannabis use during drinking on that day were associated with a greater risk for alcohol-related consequences. On days that did not involve pregaming, the use of cannabis before drinking was associated with a greater risk for negative alcohol-related consequences, whereas cannabis use after drinking was associated with less risk for consequences. These effects were observed on non-pregaming days only and not on days with pregaming.

CONCLUSIONS

Findings have implications for brief interventions with students, as analyses suggested that both cannabis use and pregaming--independent of number of drinks consumed--are risky behaviors associated with alcohol-related consequences.

Simultaneous use of alcohol and cannabis and attenuated age-related declines in alcohol and cannabis use disorder symptoms across young adulthood

Most young adults naturally mature out of high-risk substance use patterns, but it is important to identify factors that may impede normative declines. Use of alcohol and cannabis simultaneously (i.e., simultaneous alcohol and marijuana/cannabis [SAM]) is cross-sectionally associated with alcohol and cannabis concerns, and SAM use increases acute risks at the daily level. However, less is known about long-term risks of SAM use and, specifically, how SAM use relates to maturing out of alcohol and cannabis use. Using four consecutive years of survey data from young adults who reported SAM use (N=409; 1636 responses; aged 18-25 at baseline), we first estimated age-related changes in symptoms of alcohol and cannabis use disorder (AUD/CUD) using multilevel growth modeling. Findings supported a maturing out process, as both AUD and CUD symptom severity significantly declined across young adulthood, on average (4 % and 5 % per year respectively, with significant acceleration). Cross-level interactions tested whether participants' mean SAM use frequency across all four timepoints moderated age-related trajectories in AUD/CUD symptom severity. Significant interactions indicated that, relative to less-frequent SAM use, participants with more frequent SAM use showed less steep declines in AUD (1 % decrease per year vs. 6 % per year) and CUD symptoms (0 % decrease per year vs. 7 % per year); thus, SAM frequency was associated with slower/delayed maturing out of hazardous alcohol and cannabis use. Findings highlight that SAM use may be a correlate or risk-factor for prolonged high-risk substance use during young adulthood that relates to deviations from maturing out processes.

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.

Latent profile analysis of college students' alcohol and cannabis co-use patterns after recreational cannabis legalization

OBJECTIVE

Evidence is mixed on how young adults' cannabis and alcohol use and co-use patterns have changed following recreational cannabis legalization (RCL). Incorporating measures of frequency and intensity of use we examined changes in college students' use and co-use patterns following RCL.

METHOD

Four-year college students (n = 845,589) ages 18-24 years participated in the National College Health Assessment between 2008 and 2018, including students from 7 states that enacted RCL and 42 that did not. Latent profile analyses identified six patterns of use from four indicator variables tapping frequency of cannabis use and frequency and intensity of alcohol use: Abstainers, Light Alcohol Only, Heavy Alcohol Only, Predominantly Heavy Cannabis Use, Moderate Co-use, and Heavy Co-use.

RESULTS

Regression models that adjusted for time and person- and institution-level covariates indicated that students' exposure to RCL was associated with lower odds of being in the two alcohol-only use classes, higher odds of being in the Predominantly Heavy Cannabis Use, Heavy Co-Use and Abstainers classes, and was not significantly related to Moderate Co-Use class membership.

CONCLUSIONS

RCL was positively associated with patterns of frequent cannabis use and frequent and intense co-use but also with abstinence. Use of alcohol-only became less prevalent after RCL. Research on how RCL influences the prevalence of problematic patterns of substance use will inform and improve prevention efforts.

Cannabis use among adolescents and young adults during the COVID-19 pandemic: A systematic review

Background

A systematic review of the literature was performed to summarize cannabis use among adolescents and young adults during the COVID-19 pandemic. Special focus was given to the prevalence of cannabis use during COVID-19, as well as factors that may explain changes in cannabis consumption patterns.

Methods

The protocol of this systematic review was registered. Articles from seven publication databases were searched in January 2022. The inclusion criteria for studies were as follows: 1) published in English; 2) study instruments needed to include items on COVID-19; 3) conducted after January 1st, 2020; 4) published in a peer-reviewed journal, dissertation, or thesis; 5) study population ≤25 years of age; 6) study designs were limited to observational analytical studies; 7) measured cannabis use. This review excluded other reviews, editorials, and conference abstracts that were not available as full text manuscripts. Independent review, risk of bias assessment, and data abstraction were performed by two authors.

Results

Fifteen articles from the United States (n=11) and Canada (n=4) were included in this review. The findings of this review showed that the prevalence of cannabis use during the pandemic among adolescents and young adults were mixed. Some mental health symptoms, including depression and anxiety, were identified as the most commonly reported reasons for increased cannabis use during the pandemic.

Conclusions

This review highlights the inconsistencies in the prevalence of cannabis use among adolescents and young adults during the pandemic. Therapeutic interventions for mental health and continued public health surveillance should be conducted to understand the long-term effects of cannabis use among adolescents and young adults.

Interpretations and experiences of subjective effects for alcohol alone and when combined with cannabis: A mixed-methods approach

Subjective effects generally describe the feelings one has when consuming substances. There are several tools available for measuring alcohol-related subjective effects but there are reasons to believe that effects are interpreted differently across participants. The assessment of alcohol-related subjective effects is further complicated by the fact that many people use other substances with alcohol, including cannabis. The present study used a mixed-methods approach to evaluate interpretations of 21 subjective effects used in common assessments among a college student sample (N = 99; primarily White [79%], Hispanic [60%] women [74%], 72% of which reported lifetime couse of alcohol and cannabis). We sought to (a) estimate the prevalence of each effect and the amount of alcohol/number of drinks (and, for those with simultaneous use, amount of cannabis/number of hits) required to experience each effect and (b) evaluate how participants interpreted each effect that they had ever experienced when drinking (for our sample who had used only alcohol) or when simultaneously using alcohol and cannabis (for our sample who had reported simultaneous use). Across both samples, we found that several effects were far more common than others and participants had varied interpretations of each subjective effect. Further, qualitative results demonstrated that participants interpreted some subjective effects in a way that differed from the original intention of the measure. Results suggest a degree of measurement error when using common subjective effects assessment tools. Findings lay the groundwork for standardized measures of subjective effects for simultaneous use and have implications for future real-world assessment and intervention work. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

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.

Drinking contexts, coping motive, simultaneous cannabis use, and high-intensity drinking among adults in the United States

AIMS

High-intensity drinking (HID), extreme drinking considerably above the level of heavy episodic drinking (HED), is associated with long-term health and social consequences. There is limited understanding of HID beyond young adulthood. This study aims to identify concurrent risk factors for HID, comparing age differences among all adults.

METHODS

Multinomial logistic and linear regression modeling was performed using a nationally-representative sample of adults (analytic n = 7956) from the 2015 and 2020 National Alcohol Surveys. The outcomes were any HID of 8-11 drinks and 12+ drinks for men, and 8+ drinks for women, and corresponding frequencies. Concurrent risk factors included coping motive, sensation seeking, simultaneous use of alcohol and cannabis (SAC), and drinking at a bar or party. Analyses were stratified by age (18-29 vs. older) and sex.

RESULTS

For younger men, sensation-seeking was significantly associated with HID (vs. no HED) at both levels and frequency of HID 8-11 drinks, while drinking to cope was only significant for 12+ drinks. For older men, drinking to cope was a consistent predictor for both HID level and its frequency, but sensation-seeking was not significant. Both coping and sensation-seeking were significantly associated with any HID for all women, while coping was significant for HID frequency for younger women. Frequent drinking at bars and parties were associated with greater odds of HID for all adults. With HED as referent, similar patterns of (though fewer significant) associations were observed.

CONCLUSIONS

Younger and older adults share similar risk factors for HID, with coping more consistent for older men.

Alcohol and Substance Use Among the Working Age Population: A Nationwide Study of Fall-Related Emergency Department Visits

OBJECTIVE

Prior studies have linked fall-related emergency department (ED) visits among older adults to alcohol use. Characteristics related to falls in the working age population (WAP; 15-64 years) may vary with alcohol and substance use. This study aimed to identify factors associated with fall-related ED visits related to alcohol and substance use in the WAP.

METHOD

Using nationally representative 2019-2020 National Hospital Ambulatory Medical Care Survey data, fall-related ED visits within 72 hours were stratified by indication of alcohol use, substance use, and concurrent alcohol and substance use. Descriptive statistics accounting for the survey's complex design were used along with multivariable logistic regression to identify associated factors.

RESULTS

Between 2019 and 2020, an estimated 10,800,000 fall-related ED visits occurred among the WAP, with 51.7% related to alcohol use, substance use, or both. Multivariable logistic regression analysis revealed that the WAP with fall-injury ED visits were associated with alcohol use (adjusted odds ratio [AOR] = 2.3, 95% CI [1.0, 5.9]) or concurrent alcohol and substance use (AOR = 8.5, 95% CI [1.6, 43.0]), and individuals with alcohol and substance use with a depression diagnosis are twice as likely to visit EDs with fall injuries.

CONCLUSIONS

Individuals with alcohol and substance use with depression were twice as likely to visit EDs for fall injuries. Higher fall-related ED visits in the WAP were attributed to alcohol and substance use. Identified factors could improve injury prevention and timely intervention among the WAP in the United States.

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.

Addressing cortex dysregulation in youth through brain health check coaching and prophylactic brain development

The Carter Center has estimated that the addiction crisis in the United States (US), if continues to worsen at the same rate, may cost the country approximately 16 trillion dollars by 2030. In recent years, the well-being of youth has been compromised by not only the coronavirus disease 2019 pandemic but also the alarming global opioid crisis, particularly in the US. Each year, deadly opioid drugs claim hundreds of thousands of lives, contributing to an ever-rising death toll. In addition, maternal usage of opioids and other drugs during pregnancy could compromise the neurodevelopment of children. A high rate of DNA polymorphic antecedents compounds the occurrence of epigenetic insults involving methylation of specific essential genes related to normal brain function. These genetic antecedent insults affect healthy DNA and mRNA transcription, leading to a loss of proteins required for normal brain development and function in youth. Myelination in the frontal cortex, a process known to extend until the late 20s, delays the development of proficient executive function and decision-making abilities. Understanding this delay in brain development, along with the presence of potential high-risk antecedent polymorphic variants or alleles and generational epigenetics, provides a clear rationale for embracing the Brain Research Commission's suggestion to mimic fitness programs with an adaptable brain health check (BHC). Implementing the BHC within the educational systems in the US and other countries could serve as an effective initiative for proactive therapies aimed at reducing juvenile mental health problems and eventually criminal activities, addiction, and other behaviors associated with reward deficiency syndrome.

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.

Contexts of social alcohol and cannabis use among sexual minority cisgender women and gender diverse individuals: Event-level differences in alcohol and cannabis use patterns based on the sexual orientations and gender identities of substance use companions

PURPOSE

Sexual minority women and gender diverse individuals assigned female at birth (SMWGD) are at elevated risk for alcohol and cannabis use disorders. It has been posited that characteristics of SMWGD's substance use companions (i.e., sexual orientation, gender identity) may influence their own use, but few studies have tested this. The current study aimed to examine whether quantity and consequences of substance use varied based on sexual orientations and gender identities (SOGI) of SMWGD's substance use companions.

METHODS

We utilized a 30-day ecological momentary assessment study of substance use among a sample of 429 SMWGD. We examined event-level associations between characteristics of substance use companions and quantity and consequences of substance use.

RESULTS

When SMWGD used alcohol/cannabis with most SOGI groups, they engaged in heavier drinking and cannabis use. Drinking with heterosexual men and SMW was associated with more drinking consequences. Drinking in settings with more SOGI groups and with both LGBTQ+ and heterosexual individuals was associated with heavier drinking and more consequences. Many contextual aspects of cannabis use settings predicted an increased likelihood of alcohol and cannabis co-use, while few contextual aspects of drinking settings were associated with co-use.

CONCLUSION

Results suggest that SMWGD engage in heavier substance use when individuals from a range of SOGI groups are present, highlighting that heavy alcohol and cannabis use is not limited to use with SMW and nonbinary individuals. Drinking in setting with more SOGI groups present (e.g., parties and bars) appears to be associated with particularly heavy drinking and consequences.

Tobacco and alcohol co-use: Lifestyle and sociodemographic factors, and personality aspects as potential predictors in the "Seguimiento Universidad de Navarra" cohort

Tobacco and alcohol co-use are two major lifestyle modifiable risk factors. Understanding the determinants of both behaviors helps to develop interventions to prevent these exposures. However, previous studies have focused on predictors of individual tobacco or alcohol use. This study aims to explore the potential predictors of tobacco and alcohol co-use among Spanish university graduates from the "Seguimiento Universidad de Navarra" (SUN) cohort study. A total of 7175 participants who were co-users of tobacco and alcohol were selected for this cross-sectional analysis. Their mean age was 39.1 years (12.04 SD) and 57.3% were women. Univariate regression models were used to select the potential predictors of tobacco and alcohol co-use, and the areas under the ROC curves (AUC) were calculated. Multivariable logistic regression models were used to create a predictive model. Baseline potential predictors included sociodemographic factors, lifestyle habits, and perceived personality aspects. In the multivariable model, the main significant potential predictors of tobacco and alcohol co-use were driving under the influence of alcohol (odds ratio [OR] = 1.65 [1.43-1.90]), drinking 1-2 cups of coffee daily (OR = 1.50 [1.24-1.84]), drinking three or more cups of coffee daily (OR = 1.61 [1.35-1.91]), and doing more physical activity than recommended (OR = 1.18 [1.02-1.34]) when compared with the reference group. Conversely, those who were married (OR = 0.87 [0.75-0.99], ate at home 7 days a week (OR = 0.69 [0.60-0.80]), or had a high perceived level of competitiveness (OR = 0.83 [0.72-0.95]) had a lower risk of co-use (AUC 0.61 [confidence interval 95% 0.59-0.63]), compared to the reference group. These results could be used by healthcare professionals, especially nurses, to effectively assess patients at higher risk of tobacco and alcohol co-use. [Correction added on 16 February 2024, after first online publication: The abstract section has been revised to provide more clarity in this version.].

Changes in co-use of alcohol and cannabis among Nordic adolescents in the 21st century: Results from the European School Survey Project on Alcohol and Other Drugs study

INTRODUCTION

In the 21st century, there has been a decline in alcohol use among adolescents in most Nordic countries, while trends of cannabis use have diverged. We explore how alcohol and cannabis use, respectively, and co-use of the two substances, have changed among Nordic adolescents. Three hypotheses are used to frame the study: (i) cannabis use has substituted alcohol use; (ii) there has been a parallel decline in both substances; and/or (iii) there has been a 'hardening' of users, implying that alcohol users increasingly use cannabis.

METHODS

Data from the European School Survey Project on Alcohol and Other Drugs, conducted among 15- to 16-year-olds in Denmark, Finland, Iceland, Norway and Sweden (N = 74,700, 49% boys), were used to explore trends of past-year alcohol and cannabis use in the period 2003-2019.

RESULTS

The proportion of adolescents reporting alcohol use decreased significantly in all Nordic countries except Denmark. The proportion of those using cannabis only was low (0.0%-0.7%) and stable in all countries. The total number of substance use occasions declined among all adolescents in all countries but Denmark. Among alcohol users, cannabis use became increasingly prevalent in all countries but Denmark.

DISCUSSION AND CONCLUSIONS

We found no support for the 'parallel decline hypothesis' in alcohol and cannabis use among Nordic adolescents. Partially in line with the 'substitution hypothesis', cannabis use accounted for an increasing proportion of all substance use occasions. Our results suggests that the co-use of alcohol and cannabis has become more common, thus also providing support to the 'hardening' hypothesis.

Age-related patterns in high-risk alcohol and cannabis use and their associations with positive and negative affect in young adulthood

OBJECTIVE

We examined age-varying associations between young adult simultaneous alcohol and marijuana/cannabis use (SAM) and heavy episodic drinking (HED) and positive and negative affect to inform harm reduction efforts.

METHODS

Young adults reporting past-year alcohol use (n = 556; ages 19-25) were recruited in a state where alcohol and nonmedical cannabis use was legal for those 21 +. Participants provided 24 repeated monthly assessments. Among those reporting past-month cannabis use on at least one survey, logistic time-varying effect models estimated (1) the age-varying prevalence of and associations between past-month SAM and HED and (2) age-varying unique associations of affect with SAM and HED.

RESULTS

There was a positive age-varying association between HED and SAM over time that was highest at age 19 (OR = 7.56), decreased until age 20.7 (OR = 3.39), increased until age 23.0 (OR = 4.85), and decreased until the association became non-significant by age 25. Negative affect was positively associated with SAM from ages 20.7 to 23.0, peaking at age 21.8 (OR = 1.36). Positive affect was positively associated with HED from ages 19.4 to 20.4 (peak OR = 1.25) and ages 22.5 to 24.5 (peak OR = 1.38). In contrast, positive affect was not uniquely associated with SAM nor negative affect with HED across ages 19-25.

CONCLUSIONS

While HED and SAM were positively associated throughout young adulthood and interventions could target them in tandem, their associations with affect suggest differential etiologic processes. Preventive intervention and harm reduction efforts should attend to psychological context in which these behaviors occur.

Associations between simultaneous use of alcohol and cannabis and cannabis-related problems in 2014-2016: evidence from the Washington panel survey

BACKGROUND

To address the research question of how simultaneous users of alcohol and cannabis differ from concurrent users in risk of cannabis use problems after the recreational marijuana legalization in Washington State.

METHODS

We used generalized estimating equations with a Poisson distribution to analyze the association between simultaneous use of alcohol and marijuana (SAM) and cannabis-related problems compared to concurrent use. The data is a longitudinal sample of drinkers and cannabis users (n = 257, 47% female) aged 18 years and older from Washington State in 2014-2016. We adjusted for survey weights to account for differential probability of selection and response rates. The primary outcome is the past-six-month CUDIT problem subscale (ranging from 0 to 28), which is the total score for seven CUDIT problem items, after excluding the three items that covered marijuana use frequency. Covariates include marijuana use frequency (daily/near daily use, regular use, or infrequent use), marijuana daily quantity, alcohol daily volume, panel survey cycle, medical marijuana recommendation, driving time to nearest marijuana outlet, age of marijuana use onset, and other demographics.

RESULTS

After adjusting for covariates, we found that compared to concurrent use, SAM was significantly positively associated with CUDIT problem subscale (IRR = 1.68, 95% CI: 1.25-2.27, p < 0.001); daily/near daily use of marijuana was strongly significantly associated with CUDIT problem subscale compared with infrequent use (IRR = 5.1, 2.71-9.57, p < 0.001) or regular use (IRR = 3.05, 1.91-4.85, p < 0.001). Secondary analyses using CUDIT total score as the outcome also showed a significant positive association with SAM compared to concurrent use (IRR = 1.17, 1.02-1.34, p < 0.05).

CONCLUSIONS

This study highlighted the importance of SAM, in addition to cannabis use frequency for predicting cannabis-related problems.

The Interaction of Cannabis Consumption with Heavy Episodic Drinking and Alcohol-induced Blackouts in Relation to Cannabis Use Consequences Among Recent Undergraduate College Cannabis Users

Introduction

Risky alcohol use patterns, characterized by heavy episodic drinking (HED) and alcohol-induced blackout, are prevalent in college students. However, it is not clear if experiencing HED and blackout among college-attending cannabis users heightens risk for adverse cannabis use consequences. The purpose of this study was to examine whether heavy episodic drinking and blackout episodes moderate the relationship between cannabis consumption and cannabis use consequences among college students.

Methods

Undergraduate college students (n = 4331) were recruited from a Midwest University in 2021. This analysis used a subset of data from past 6-month cannabis users (n= 772; 17.8% of the full sample). Among cannabis users, 64.5% identified as female and 87.8% were White with an average age of 19.99 (SD=2.88). A linear regression was conducted with two two-way interactions of cannabis consumption and HED frequency as well as cannabis consumption and alcohol-induced blackout episodes.

Results

Results showed a statistically significant positive association between cannabis consumption and cannabis use consequences (B=0.73, p<.001), adjusting for the other variables in the model. Blackout, but not HED, was a significant moderator (B=0.19, p=.003).

Discussion

The findings of this study indicate that blackout experiences amplify the relationship between cannabis use and cannabis-related consequences among college students. This underscores that blackouts not only signal a risk of problematic drinking but also exacerbate the association between cannabis use and its negative consequences.

Conclusion

Findings may inform college campus interventions targeting cannabis and alcohol concurrent-users who experience alcohol-induced blackouts to reduce their additional risk for cannabis-related consequences.

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.

Chronic Pain and Cannabis Use Frequency, Intensity, and Severity in Young Adults

BACKGROUND

Cannabis use is common among young adults and is associated with many physical and mental health problems. Persons with chronic pain may be particularly susceptible to using cannabis at high rates, including for analgesic purposes, thus exposing themselves to greater risk of cannabis-related problems. However, little research has examined connections between chronic pain and cannabis use in the young adult population.

MATERIALS AND METHODS

Participants were young adults from the community who were recruited for a larger health behaviors study. The present sample included 403 persons from this larger sample who reported cannabis use in the past 90 days. Participants completed measures of demographic characteristics, cannabis and alcohol use, and chronic pain.

RESULTS

This young adult sample reported using cannabis on an average of 47.1 of the past 90 days, and 20.1% reported chronic pain. Chronic pain was associated with greater cannabis use frequency (IRR = 1.35, 95%CI 1.15; 1.57, p < 0.001), intensity (IRR = 1.61, 95%CI 1.18; 2.21, p = 0.003), and negative consequences (IRR = 1.23, 95%CI 1.02; 1.48, p < 0.030).

DISCUSSION

In this sample of young adults who use cannabis, chronic pain was significantly associated with frequent, intense cannabis use, as well as more cannabis-related negative consequences. These findings suggest that chronic pain may be a marker for a particularly high-risk pattern of cannabis use in this age group, thus identifying an especially vulnerable subset of young adults who may require heightened research and clinical attention.

Too Tired to Think: Within and Between-Person Relations Among Impulsive Traits, Sleep Duration, and Mental Health Outcomes

Heavier drinking and depression are common mental health concerns in the USA, yet few studies have sought to understand transdiagnostic risk factors for both. Two health-focused risk factors are impulsive personality traits and sleep duration, but research typically separates the two, precluding additive and interactive relations. The current study sought to test a theoretical model where risk conferred from impulsive traits is heightened when individuals have reduced sleep. Public-access data from the National Longitudinal Study on Adolescent to Adult Health (Add Health) were used to test study hypotheses. Participants reported on impulsive traits (i.e., lack of premeditation, sensation seeking), sleep duration, depression, and drinking across three waves spanning adolescence, emerging adulthood, and adulthood. Multilevel models distinguished risk processes at the between- vs. within-person level. At the between-person level, sensation seeking predicted drinking whereas premeditation predicted depression. Additionally, within-person deviations in both traits were associated with drinking, whereas within-person deviations in premeditation were associated with depression. Sleep duration was protective against outcomes at both levels. However, main effects were qualified by interactions at both levels, such that having below average sleep duration heightened the effects of premeditation at the between-person level, whereas within-person decreases in sleep heightened the effects of sensation seeking at the within-person level. Findings support a theoretical model where poor sleep exacerbates risk conferred from impulsive traits. Risk conferred from impulsive traits diverged based upon level of analysis, suggesting that global and just-in-time interventions may benefit from targeting specific impulsive traits as well as sleep.

Prevalence of probable substance use disorders among children in Ugandan health facilities

BACKGROUND

Globally, there is a concerning surge in the prevalence of substance use among adolescents and children, creating a substantial public health problem. Despite the magnitude of this issue, accessing healthcare explicitly for substance use remains challenging, even though many substance users frequently visit healthcare institutions for other health-related issues. To address this gap, proactive screening for substance use disorders has emerged as a critical strategy for identifying and engaging patients at risk of substance use. The purpose of this study was to investigate the prevalence of probable alcohol and other substance use disorders, and associated factors, among children aged 6 to 17 years old attending health facilities in Mbale, Uganda.

METHODS

We conducted a health facility cross-sectional study, involving 854 children aged 6-17 years. The prevalence of probable alcohol and other substance use disorders was assessed using a validated Car, Relax, Alone, Forget, Friends, Trouble (CRAFFT) screening tool. Univariable and multivariable modified Poisson regression analyses were performed using STATA 15 software.

RESULTS

The overall prevalence of probable alcohol use disorders (AUD) and other substance use disorders (SUD) was 27.8% (95% CI 1.24-1.31) while that of probable AUD alone was 25.3% (95% CI 1.22-1.28). Peer substance use (APR = 1.24, 95% CI 1.10-1.32), sibling substance use (APR = 1.14, 95% CI 1.06-1.23), catholic caregiver religion (APR = 1.07 95% CI 1.01-1.13), caregiver income of more than $128 (APR = 0.90, 95% CI 0.82-0.98), having no parental reprimand for substance use (APR = 1.05, 95% CI 1.01-1.10) and having no knowledge of how to decline an offer to use substances (APR = 1.06, 95% CI 1.01-1.12) were found to be significantly associated with probable AUD/SUD.

CONCLUSIONS

Our findings suggest a high prevalence of probable AUD and SUD among children and adolescents visiting healthcare facilities for other conditions, along with a strong link between AUD and SUD prevalence and social factors. The implication for our healthcare system is to actively screen for and treat these conditions at primary healthcare facilities.

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.

Are you thinking what I'm thinking? Defining what we mean by "polysubstance use."

The rise in drug overdoses and harms associated with the use of more than one substance has led to increased use of the term "polysubstance use" among researchers, clinicians, and public health officials. However, the term retains no consistent definition across contexts. The current authors convened from disciplines including sociology, epidemiology, neuroscience, and addiction psychiatry to propose a recommended definition of polysubstance use. An iterative process considered authors' formal and informal conversations, insights from relevant symposia, talks, and conferences, as well as their own research and clinical experiences to propose the current definition. Three key concepts were identified as necessary to define polysubstance use: (1) substances involved, (2) timing, and (3) intent. Substances involved include clarifying either (1) the number and type of substances used, (2) presence of more than one substance use disorder, or (3) primary and secondary substance use. The concept of timing is recommended to use clear terms such as simultaneous, sequential, and same-day polysubstance use to describe short-term behaviors (e.g., 30-day windows). Finally, the concept of intent refers to clarifying unintentional use or exposure when possible, and greater attention to motivations of polysubstance use. These three components should be clearly defined in research on polysubstance use to improve consistency across disciplines. Consistent definitions of polysubstance use can aid in the synthesis of evidence to better address an overdose crisis that increasingly involves multiple substances.

Daily level examination indicates that positive affect, but not negative affect, is associated with alcohol and marijuana use among adolescents and young adults

OBJECTIVE

Although there is growing evidence that alcohol use at the daily level is associated with positive but not negative affect, results are mixed when examining marijuana use and simultaneous alcohol and marijuana (SAM) use (i.e., use with overlapping effects). In addition, less is known about these daily level associations among diverse samples of adolescents and young adults. The present study will address these gaps.

METHOD

Participants (N = 1,006; 57.3% female, 43.1% White, Non-Hispanic, ages 15-25; Mage = 20.0) were part of a study on substance use that consisted of a 3-week ecological momentary assessment (EMA) burst design (eight surveys per week, up to 2×/day) that was repeated quarterly over a 12-month period.

RESULTS

Within-person results indicated that on days with elevated positive affect, participants reported consuming more drinks, whereas positive affect was not significant for hours high from marijuana. In addition, on days with elevated negative affect, participants reported fewer hours high from marijuana. No association was found between negative affect and number of drinks. Finally, within-person results indicated that on alcohol or marijuana days with elevated positive affect, individuals were more likely to report SAM use. There was no association found between negative affect and SAM use.

CONCLUSIONS

Results have implications such that in-the-moment interventions for alcohol and SAM use may be more salient when individuals have higher positive affect than average, whereas such interventions may be more relevant for marijuana use when negative affect is lower compared to average levels. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

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.

Sex and Gender Differences in Simultaneous Alcohol and Cannabis Use: a Narrative Review

Purpose of Review

The aim is to review recent literature on sex and gender differences in patterns of use, motives, pharmacological effects, and consequences of simultaneous alcohol and cannabis use (SAC).

Recent Findings

Men engage in SAC more frequently than women. Women may have more substance-specific motives for use, while men tend to consistently endorse social/enhancement motives for both alcohol and cannabis. Regarding pharmacological effects, women experience the same subjective effects as men do at lower levels of use, with some evidence that women modulate cannabis use during simultaneous use episodes to avoid greater subjective intoxication. Finally, women appear more vulnerable to experiencing a range of positive and negative consequences from SAC relative to men.

Summary

Research has identified several important sex/gender differences in SAC and its correlates and consequences. However, research has primarily focused on white and cisgender populations, with a need for more research among racial/ethnic and gender minorities.

Cannabis to cope with COVID-19 in college

Objective: Cannabis use in college students has increased over time and is linked to negative consequences. During the COVID-19 pandemic, many students experienced greater stress, which could heighten cannabis use and related consequences. This study was designed to clarify motivations for cannabis use that may link pandemic-related stressors to time spent high and cannabis-related consequences.Participants: A total of 488 cannabis-using college students (75% women) participated.Methods: A cross-sectional survey was administered in Fall 2020 and Spring 2021 to examine students' experiences during the pandemic.Results: Indirect effects revealed that pandemic-related social stressors were linked to coping and boredom motives, and in turn, more hours spent high and cannabis-related consequences. Similarly, pandemic-related distress was associated with more coping motives and in turn, more hours spent high and cannabis-related consequences.Conclusions: Findings suggest prevention and intervention efforts may benefit from emphasizing alternative coping methods, including enhanced social support, during prolonged stressors.

In vitro evaluation of cell viability and expression profile of growth factors in mouse Sertoli cells exposed to Delta-9-tetrahydrocannabinol: a mechanistic insight into the cannabinoid-induced testicular toxicity

The potentially adverse effects of cannabis (marijuana), a common leisure compound, on male reproductive performance are a reason for concern. δ-9-tetrahydrocannabinol (THC), the primary active component of marijuana alters testicular cells' proliferation and function which affects male fertility and causes testicular cells dysfunction and apoptosis. The main objective of this study was to investigate the possible mechanism underlying the toxic effects of THC with a mechanistic insight into Sertoli cell-based reproductive dysfunction. The Mus musculus Sertoli cell line (TM4) was cultured and exposed to different concentrations of THC and, MTT (3-(4, 5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was then performed for evaluating cell viability. The expression of caspase-3 gene and genes related to growth factors were analyzed by real-time RT-PCR. Western blotting was performed for evaluating protein expression level. THC concentration-dependently decreased the TM4 viability with a significant effect starting at concentration of 1 μM and reaching about 75% of the control level at the concentration of 50 μM (IC25). Moreover, caspase-3 mRNA expression levels significantly increased while growth factors mRNA levels decreased in THC-exposed cells compared to unexposed cells. There was also a significant reduction in related protein levels in THC group. Administration of the THC promotes cytotoxic and apoptotic effects on TM4 cells partly through down-regulation of growth factors expression. Increased apoptosis, over expression of caspase-3, and down-regulation of growth factors expression in Sertoli cells exposed to THC may be a reflection of THC-induced testicular toxicity, which may be partly involved in infertility associated with marijuana smoking or medical cannabis use.

Patterns of Simultaneous and non-Simultaneous Use of Cannabis and Alcohol Among American Indian Adolescents

Background

American Indian (AI) adolescents report earlier initiation and higher rates of cannabis and alcohol use compared to their non-AI peers. Simultaneous cannabis and alcohol (SCA) use is increasingly common. A primary goal of our research was to identify profiles of cannabis and alcohol use, including SCA use, among AI adolescents using latent class analysis (LCA).

Method

Data from 1,673 7th - 12th grade students attending 45 reservation-area schools throughout the U.S. who reported using alcohol and/or cannabis in the past year were used to identify the latent classes. Multinomial logistic regression analysis determined associations of sex, grade, and multiethnicity to class membership.

Results

A four-class solution was found: 1) SCA-Heavier Use (16.1%); 2) SCA-Lighter Use (25.2%); 3) Primarily Cannabis Use (33.3%); and 4) Primarily Alcohol Use (25.4%). Multinomial regression showed higher grade, identifying as multiethnic, and being female were associated with higher likelihood of membership in the SCA class.

Conclusion

AI adolescents were more likely to be classified in the Primarily Cannabis Use class as compared to all other classes. Characterizing profiles of use may help identify those engaging in risky or co-use and help researchers and clinicians better understand how AI adolescents engage with alcohol and marijuana.

"What was the vibe you were going for?" SAM Behaviors and Socialization During the COVID-19 Pandemic, a Qualitative Approach

Introduction

Marijuana use is at historic highs amongst college-aged adults, who are more likely to engage in simultaneous alcohol and marijuana use (SAM) than other age cohorts. For college students, the COVID-19 pandemic is a unique transitory phenomenon that led to isolation, as well as changes in socialization, academic environments, and substance use. This exploratory qualitative study aims to understand SAM socialization and motivation behaviors among college students.

Methods

Semi-structured qualitative interviews (N=32) were conducted across the United States from January 2021-April 2021via Zoom. Interviews were then transcribed, then a thematic analysis was conducted in Atlas.ti.

Results

The sample was primarily college juniors (mage=21). Since the pandemic, half of the participants increased SAM, whereas the other half decreased SAM. SAM was reported in different categories including primarily with friends, but, much less with partners and with roommates. More than half of the sample indicated that they used SAM alone. Motivations to engage in SAM included relaxing, socializing, offsetting stressors specific to the COVID-19 pandemic, and relieving general stress, anxiety and boredom.

Conclusion

The COVID-19 pandemic impacted college students' substance use in interesting ways. Understanding the behaviors of SAM in the context of the COVID-19 pandemic is crucial due to the legalization of marijuana in many states. This understanding has significant implications for prevention strategies and potential policy interventions. Our study yielded findings regarding the impact of socialization on SAM. We discovered that not only does socialization affect SAM, but the specific contexts and motivations behind these behaviors also play a crucial role, which adds to our developing understanding of SAM behavior.

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).

A Longitudinal Analysis of Monthly Changes in Substance Use in Relation to Negative Consequences From Alcohol and Cannabis Use in a Community Sample of Young Adults

OBJECTIVE

Experiencing negative substance use consequences may deter future use, alter patterns of substance use (e.g., substituting one substance for another, combining substances), or point to a sustained pattern of engaging in heavy or frequent use. We used monthly data to examine relationships between negative alcohol and cannabis use consequences experienced in one month and changes in use the following month.

METHOD

Data were from 508 individuals (59% female; ages 18-23 years at enrollment) who were surveyed monthly for 2 years and used both alcohol and cannabis during the study period. Multilevel models assessed within-person associations between monthly fluctuations in substance-related negative consequences and the next month's substance use (i.e., typical drinks per week, cannabis use frequency, and simultaneous alcohol and cannabis/marijuana [SAM] use), controlling for the prior month's substance use.

RESULTS

Positive associations were found between alcohol consequences and the following month's alcohol use and between cannabis consequences and subsequent cannabis use, although only the cannabis association was statistically significant. There was little evidence of effects of cannabis consequences on the next month's alcohol use or alcohol consequences on the next month's cannabis use. Cannabis consequences had a positive and statistically significant association with the next month's SAM use. Within-substance positive associations were strongest for physical alcohol consequences and cannabis consequences of low motivation, memory problems, and trouble breathing.

CONCLUSIONS

Experiencing negative cannabis use consequences predicted more frequent cannabis use and greater chance of SAM use 1 month later. Results point to negative consequences, along with prior use, indicating risk for future use.

Profiles of alcohol and cannabis protective behavioral strategies use across two large, multi-site college student samples of concurrent alcohol and cannabis users

Concurrent use of alcohol and cannabis among college students is common and confers greater harms than the use of either of these substances alone. Large and growing bodies of literature have demonstrated the independent utility of behaviors used before, during, after, or instead of alcohol and cannabis use that minimize related harms (i.e., protective behavioral strategies [PBS]). However, little is known about the relationship between alcohol and cannabis PBS and their joint influence on harms among college students who concurrently use alcohol and cannabis. In the present study, we used data from two large, multi-site samples of college students, and restricted analyses to those who reported at least one episode of alcohol and cannabis use in the past 30 days (Study 1: N = 1104[Mage = 20.3, SD = 3.8; 70.0 % female; 79.5 % white]; Study 2: N = 2034[Mage = 20.2, SD = 3.2; 69.1 % female; 76.6 % white]). A latent profile analysis supported a 4-profile solution that was largely consistent across samples: Profile 1 (low alcohol/cannabis PBS; 8.8-11.9 %), Profile 2 (average alcohol/cannabis PBS; 33.1-37.7 %), Profile 3 (average alcohol PBS/low cannabis PBS; 16.3-25.2 %), and Profile 4 (high alcohol/cannabis PBS; 29.8-37.2 %). Profile 4 reported the least alcohol/cannabis use, fewest negative alcohol-/cannabis-related consequences, and lowest alcohol/cannabis use severity. In contrast, Profile 1 was the opposite for alcohol-related outcomes, and Profile 3 was the opposite for cannabis-related outcomes. These findings are preliminary but may suggest that targeting both alcohol and cannabis PBS in intervention is generally beneficial except some groups at risk for a particular substance may benefit from increased focus on that substance in intervention.

A determination of the aerosolization efficiency of drugs of abuse in a eutectic mixture with nicotine in electronic cigarettes

Eutectic mixtures can be formed by adding drugs other than nicotine (DOTNs) to nicotine-based e-liquids in electronic cigarettes (e-cigarettes). Thus, the interaction between nicotine e-liquids and DOTNs must be evaluated. Presented is the change in e-cigarette aerosolization of nicotine and methadone alone versus a 1:1 nicotine:methadone mixture to evaluate the possible formation of a eutectic mixture that can result in an increase of drug delivery. E-liquids were prepared in-house using 1:1 propylene glycol (PG):vegetable glycerin (VG) as a base plus nicotine, methadone hydrochloride, or 1:1 nicotine:methadone hydrochloride. The e-liquids were aerosolized via an automated vaping machine using parameters adopted from the Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA) E-cigarette Task Force method. Drug recovery was determined by capturing the aerosol from 15 puffs generated by the e-cigarette. Concentrations of nicotine and methadone aerosolized were determined by gas chromatography-mass spectrometry using nicotine (n = 3), methadone (n = 3), and combined nicotine/methadone e-liquids (n = 3), each prepared in-house at 12 mg/ml. The concentration of nicotine and methadone in 15 puffs of the single drug e-liquids were determined to be 1.60 ± 0.20 and 2.67 ± 0.12 mg, respectively. The concentration of nicotine and methadone in 15 puffs of the multidrug e-liquid were determined to be 3.66 ± 0.49 and 3.65 ± 0.10 mg, respectively. The single nicotine and methadone e-liquids had recoveries of 70 ± 0.1% and 84 ± 0.1%, respectively. In the 1:1 mixture, the recovery of both drugs increased. The development of a eutectic mixture can promote aerosolization of the drug and deliver a greater dose to the user.

Reasons for not drinking among young adults with simultaneous alcohol and cannabis use: A latent class analysis applied to daily diary data

Simultaneous alcohol and cannabis use (i.e., simultaneous use) is prevalent among young adults and often associated with negative consequences. Understanding reasons for not drinking (RND) may provide insight into a key intervention target for reducing negative consequences associated with simultaneous use. RND may vary on a day-to-day level, and multiple RND may be endorsed on a given day. Latent class analysis (LCA) of daily diary data is a nuanced approach that can identify complex patterns of daily RND as well as its day- and person-level covariates. The current study was a secondary data analysis of daily diary data from young adults who engaged in heavy drinking and recent simultaneous use (n = 154). We aimed to: (1) characterize daily RND, (2) use LCA to classify day-level patterns of RND, and (3) compare latent classes on same-day variables (i.e., positive and negative affect, day of the week), previous-day variables (i.e., substance use, intoxication level, consequences), and person-level characteristics (i.e., age, sex, baseline substance use frequency, simultaneous use motives). Participants completed up to 14 consecutive diaries. Multilevel LCA identified four classes of heterogeneous daily RND profiles. Daily RND classes significantly differed in terms of day of the week, previous day quantity of cannabis use, and several baseline variables (age, typical substance use, simultaneous use motives). Study findings offer preliminary support for heterogeneous RND classes among young adults engaging in simultaneous use and suggest multiple avenues for future research.