An examination of consequences among college student drinkers on occasions involving alcohol-only, marijuana-only, or combined alcohol and marijuana use

Day-level associations among alcohol use, simultaneous alcohol and cannabis use, and both regretted and positive romantic/sexual experiences

BACKGROUND

Young adults who drink heavily, including those who simultaneously use cannabis, experience both positive and regretted romantic/sexual experiences. Both gender and past sexual assault severity may also play a role in the valence of romantic/sexual experiences. The current study focuses on day-level correlates of romantic/sexual experiences, assessing whether: (1) number of drinks or simultaneous alcohol and cannabis use (vs. alcohol only) are associated with likelihood of regretted or positive romantic/sexual experiences and (2) past sexual assault severity or gender moderate these associations.

METHODS

Two hundred and one young adults (Mage = 22.06) reporting high intensity drinking (8+/10+ drinks for females/males) completed baseline and 28 daily assessments of alcohol use, simultaneous use, and romantic/sexual experiences.

RESULTS

Consumption of more drinks increased likelihood of both positive and regretted romantic/sexual experiences. Simultaneous alcohol and cannabis use had no effect on positive romantic/sexual experiences. There was a significant interaction between simultaneous use and gender in the prediction of a regretted romantic/sexual experience when controlling for number of drinks. Among women, simultaneous use (vs. alcohol only) significantly decreased likelihood of regretted romantic/sexual experiences. Among men, simultaneous use was unrelated to likelihood of regretted romantic/sexual experiences. Past sexual assault was not a significant moderator of effects of either number of drinks or simultaneous use.

CONCLUSIONS

Among heavy-drinking young adults, a greater number of drinks is associated with both more regretted and positive romantic/sexual experiences. Findings highlight a unique protective effect of simultaneous use for women, even when controlling for how much alcohol is being consumed.

Simultaneous use of alcohol, cannabis, and energy drinks predicts increased daily alcohol consumption and alcohol consequences

Simultaneous alcohol and cannabis (SAM) use and alcohol mixed with energy drinks (AmED) days are associated with heavier drinking and negative consequences compared to alcohol-only days. However, it remains unclear if SAM and AmED days differ from one another in terms of consumption and negative consequences. It also remains unclear how often days characterized by both SAM + AmED occur and if these days are associated with incremental risk for heavier drinking and negative consequences. College students who engage in SAM use and AmED completed a 30-day timeline followback interview. Day-level data on drinking days were curated to test whether days characterized by alcohol only, SAM use only, AmED use only, or SAM + AmED were associated with increased drinking quantity, negative alcohol consequences, and positive alcohol consequences. Twenty-one percent of drinking days were AmED days, 19% were SAM days, and 15.4% were SAM + AmED days. SAM-only, AmED-only, and SAM + AmED days were associated with increased drinking and negative consequences compared to alcohol-only days. However, SAM-only and SAM + AmED (but not AmED-only) days were associated with more positive consequences than alcohol-only days. SAM-only and AmED-only days did not differ in drinking quantity or consequences, whereas SAM + AmED days were associated with increased drinking and negative (but not positive) consequences compared to both SAM-only and AmED-only days. Combined SAM + AmED days are common and associated with increased risk for negative outcomes. Prevention efforts should consider how to reduce the occurrence of SAM + AmED use and how to reduce risk on days when it does occur. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

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.

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.

Prospective examination of how alcohol consumption might drive changes in urgency and drinking motives over the first year of college

Objective: Negative and positive urgency are risk factors for alcohol escalation during college, partly through increasing motives for alcohol use, which then contribute to subsequent drinking. Research has focused on the causal direction from trait to motives to alcohol consumption. The current study conducted an initial test of how alcohol use might drive changes in urgency, and subsequent changes in motives over the first year of college. Participants: 418 first-year college students (Mage = 18.16, 73.7% female, 86.5% White) were sampled at three timepoints. Methods: Mediation models were used to test hypotheses. Results: Alcohol use at baseline predicted increased enhancement motives through increased positive urgency (B = .0028, 95% CI [.0000, .0007]). Alcohol use at baseline did not predict coping motives through changes in negative urgency (B = .0002, 95% CI [-0.0020, .0030]). Conclusions: Changes in positive urgency and enhancement motives secondary to alcohol use appear to occur early in one's drinking history, making them prime targets for early prevention strategies.

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.

Compliance and response consistency in a lengthy intensive longitudinal data protocol

Research on real-world patterns of substance use increasingly involves intensive longitudinal data (ILD) collection, requiring long assessment windows. The present study extends limited prior research examining event- and person-level influences on compliance and response consistency by investigating how these behaviors are sustained over time in an ILD study of alcohol and cannabis co-use in college students. Participants (n = 316) completed two 28-day bursts of ILD comprising five daily surveys, which included a morning survey of prior-day drinking. We used linear mixed effects models in a multilevel interrupted time series framework to evaluate the associations of time and measurement burst with (a) noncompliance (count of missed surveys) and (b) response consistency (difference between same-day report of drinking and morning report of prior-day drinking). We observed that time was positively associated with noncompliance, with no discontinuity associated with measurement burst. The slope of time was more positive in the second burst. Neither time nor measurement burst were significantly associated with consistent reporting. However, survey nonresponse and consistency of responding appeared to be impacted by the same-day use of substances. Overall, compliance decreased while consistency was stable across the duration of a lengthy ILD protocol. Shorter assessment windows or adaptive prompting strategies may improve overall study compliance. Further work examining daily burden and context is needed to inform future ILD design. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

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.

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).

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.

Differences in the relation of binge drinking and prescription drug misuse to suicide ideation and attempts between college-aged adults and adults above the age of 25: Findings from the 2015-2019 National Survey on Drug Use and Health (NSDUH)

OBJECTIVE

To clarify the role of age in risk associated with drug misuse and binge drinking, this study examines the differential relations of binge drinking and prescription drug misuse to risk of suicidal ideation and attempts in young adults of college age (18-24) compared to those above the age of 25.

METHODS

We used data from the National Survey on Drug Use and Health (NSDUH) for the years 2015 through 2019 (N = 269,078).

RESULTS

The study found that, for adults above college age, the presence of any past-month binge drinking was associated with a higher likelihood of past-year suicide ideation (b = 0.427, OR = 1.532, 95%CI [1.388, 1.692]) and attempts (b = 0.637, OR = 1.891, 95%CI [1.271, 2.813]) compared to college-aged adults. Similarly, past-month prescription drug misuse showed stronger associations with past-year suicide ideation (b = 0.831, OR = 2.297, 95%CI [1.952, 2.701]) and attempts (b = 0.539, OR = 1.715, 95%CI [1.264, 2.327]) in adults above college age.

CONCLUSION

These findings highlight that binge drinking and prescription drug misuse appears to become more strongly associated with suicide ideation and attempts after adults age beyond young adulthood.

Daily Stress, Drinking Motives and Alcohol Co-Use with Other Drugs

Background: Recent evidence indicates that alcohol and other substance co-use, compared to alcohol-only use, might be more closely associated with negative reinforcement processes, and thus more likely during periods of increased stress. The present study examined this possibility by using data from an intensive longitudinal (daily) study of college student drinkers (N = 1461, 54% women). We also examined individual differences in coping and enhancement drinking motives as predictors of alcohol and other substance co-use. Results: We used multilevel multinomial logistic regression to predict, relative to alcohol-only days, the likelihood of alcohol co-use with either cigarettes or marijuana, along with alcohol use with multiple substances and other substance-only use from daily interpersonal and academic stress, day-of-the-week, sex, and individual differences in coping and enhancement drinking motives. We found that, relative to alcohol-only, alcohol and marijuana co-use was more likely, and non-alcohol related substance use was less likely, on weekends. Alcohol and marijuana co-use was less likely, and other substance-only use was more likely, on days characterized by greater academic stress, whereas alcohol and cigarette co-use was more likely on days characterized by greater interpersonal stress. Individuals with higher levels of drinking to cope motivation were more likely to engage in alcohol and cigarette co-use, other substance-only use, and alcohol plus multiple substances, relative to alcohol-only. Individuals with higher levels of enhancement motives were more likely to engage in all types of alcohol and other substance co-use and other substance-only use relative to alcohol-only. Conclusions: Findings are discussed in terms of the complex nature of different patterns of co-use patterns when evaluating indicators of positive- and negative-reinforcement processes.

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.

Characterizing Alcohol Consumption and Positive and Negative Consequences During Simultaneous Alcohol and Cannabis Use Events

OBJECTIVE

Young adults who engage in simultaneous alcohol and cannabis use report heavy use of both substances. Event-level studies examining differences between consequences experienced on simultaneous use compared with single substance use days have been mixed. Although studies often control for alcohol use levels, few have examined how quantity of alcohol may influence consequences experienced on simultaneous use days. Furthermore, little research has examined the relationship between simultaneous use and positive consequences or explored individual consequences. This study examined differences in consequences experienced on simultaneous use versus single substance use days (alcohol-only, cannabis-only) including endorsement of specific consequences and examined the relationship among simultaneous use, consequences, and alcohol consumption.

METHOD

Young adults who engage in simultaneous use (N = 86) completed 30 days of daily surveys reporting substance use and positive and negative consequences.

RESULTS

Simultaneous use days were associated with more negative and positive consequences than single substance use (alcohol-only and cannabis-only) days. We also examined endorsement of specific positive and negative consequences on alcohol-only, cannabis-only, and simultaneous use days. The effect of day type (simultaneous use vs. alcohol-only) on consequences was moderated by alcohol quantity. On lighter drinking days, more positive and negative consequences were endorsed if it was a simultaneous use versus alcohol-only day. On heavier drinking days, number of consequences did not differ between simultaneous use and alcohol-only days.

CONCLUSIONS

Findings from this study point to simultaneous use as both reinforcing and high risk and highlight the importance of intervening even on lighter drinking simultaneous use occasions to reduce harms.

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.

Alcohol and cannabis use among rural university students: A quantitative analysis of barriers to care, student resilience, and school climate

Objective: This article examines impacts of student resilience, school climate, and barriers to mental health care on problematic drinking behavior and cannabis use among rural university students. Participants: A total of 948 students from a public university in a southeastern state that completed the 2019-2020 Healthy Minds Study. Methods: Cross-tabulations and multivariate logistic regression analyses were employed to test study hypotheses. Results: Students who binge drink are more likely to engage in problematic drinking behaviors than students who do not binge drink; students who engage in problematic drinking are more likely to use cannabis than those who do not engage in problematic drinking. As students face more barriers to mental health care, they are more likely to engage in problematic drinking and cannabis use; students who are more resilient are less likely to engage in problematic drinking. Conclusions: To promote health and wellbeing, universities must understand factors that impact substance use among students.

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.

Associations of daily alcohol, cannabis, combustible tobacco, and e-cigarette use with same-day co-use and poly-use of the other substances

BACKGROUND

Young adults frequently use alcohol, cannabis, and tobacco together. Given the increased prevalence of e-cigarette use and recreational cannabis use, we investigated daily patterns of alcohol, cannabis, and tobacco use and distinguished combustible tobacco from e-cigarettes.

METHODS

Young adult college students (N=341) reporting past-month alcohol and cannabis use "at the same time so that their effects overlapped" completed two 28-day bursts of repeated daily surveys. Exposures were day- and person-level use of each substance. Outcomes were (1) same-day co-use of each remaining substance or (2) poly-use of the other substances.

RESULTS

Daily use of alcohol, cannabis, combustible cigarettes, and e-cigarettes increased the odds of same-day co-use of the other substances (except combustible tobacco with e-cigarettes) and each poly-use outcome. The influence of person-level substance use on daily substance use was less consistent. Only e-cigarette use increased the odds of daily alcohol use. Use of either tobacco product but not alcohol increased the odds of daily cannabis use. Person-level alcohol and cannabis use increased the odds of daily use of either tobacco product but use of one tobacco product was not associated with daily use of the other product.

CONCLUSIONS

These findings increase our understanding of emerging daily patterns of alcohol, cannabis, and tobacco co-use, and the impact of different tobacco products. Future work is needed to extend this research into non-college samples and people who use tobacco but do not use alcohol and cannabis simultaneously, and examine daily chronologies of multiple substances that could serve as dynamic markers of risk.

A 2-year follow-up of the effects of combined binge drinking and cannabis consumption on academic performance and adjustment in Spanish third-year university students

Introduction

The study was based on 2-year follow-up of the effects of binge drinking and cannabis co-consumption on academic performance and adjustment in Spanish Third-Year University Students and to further explore the impact of academic adjustment on this relationship.

Methods

A total of 144 students (aged 19-20 years) enrolled in the third year of university completed the study. The students were recruited during in first academic year (T1) via a survey that included items regarding the use of alcohol (AUDIT-C), cannabis and other drugs and demographic variables. Then, participants meeting the study criteria were then selected and invited by e-mail to a clinical (face-to face) structured interview. The participants completed a calendar of alcohol consumption during the 6 months prior to the interview (Alcohol Timeline Follow back), and recorded cannabis consumption in 3 months prior to the interview. To examine the effects of alcohol and cannabis co-consumption on the outcome variables, we categorized participants into three consumption groups (i.e., control, BD, and BDCA) based on the number of BD days and cannabis unit scores.

Results

Binge drinking and cannabis co-consumption in first-year students was significantly associated with poor academic performance and adjustment after 2 years of undergraduate study. Relative to controls, co-consumers (BDCA) reported significantly lower academic and personal-emotional adjustment to university as well as poorer performance. Mediation analysis showed that academic adjustment explains the mechanism by which BDCAs perform less well, mediating the relationship between co-consumption and academic performance, with an indirect effect representing 64.61% of the total effect. Furthermore, the mediating effect of academic adjustment was maintained after controlling for academic adjustment and baseline grade point average (T1).

Conclusion

This prospective follow-up study helps to further our knowledge of how combined binge drinking and cannabis consumption may affect university adjustment and academic success in Spanish university students Overall, the study results should encourage health professionals, educational psychologists and academic institutions to take ownership of the need for support and involvement in prevention, as well as for provision of guidelines for implementing appropriate intervention strategies.

Frequency matters: Relations among alcohol and cannabis co-use frequency and alcohol use disorder symptoms in emerging adults

Emerging adult alcohol and cannabis co-use is on the rise and enacts risk for alcohol misuse/alcohol use disorder (AUD). However, few studies have differentiated whether levels of cannabis use (rather than any cannabis use) moderate between-person risk. Considering low-frequency co-users may use both substances via substitution, low-risk/frequency co-use may not enact the same risk for AUD as higher risk co-use. The present study sought to test this assertion. Public access data on emerging adults from the National Study on Drug Use and Health were used (2002-2019; N = 231,681). Participants reported on their past year alcohol use, cannabis use, as well as AUD symptoms. Regression models tested whether levels of cannabis use frequency moderated the association between alcohol use frequency and AUD symptom counts. A significant interaction of cannabis use frequency by alcohol use frequency predicting AUD symptoms was detected. Individuals who co-used alcohol and cannabis reported more AUD symptoms than those who only used alcohol at the same frequency or less. However, co-use was associated with lower AUD symptom counts than alcohol-only use at higher frequency. Findings suggest that all co-users (and alcohol-only users) are not necessarily created equal, and that relations among co-use and risk for AUD symptoms are complex. Rather than a dichotomy of co-users versus alcohol-only users, between-group risk may depend on frequency of both alcohol and cannabis use. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

High Spirits? Exploring "Halloweekend" Alcohol and Cannabis Use Among Heavy-Drinking College Students

OBJECTIVE

Specific events are associated with heavier and riskier substance use behaviors among college students, including holidays like Halloween, which may include several days of themed parties/events ("Halloweekend"). The current study compared drinking, pregaming (i.e., fast-paced drinking before going out for the night), cannabis use, same-day alcohol and cannabis co-use, and negative alcohol-related consequences over Halloweekend compared with two adjacent non-Halloween weekends among a sample of heavy-drinking university students.

METHOD

Participants (N = 228; 65% female) provided 28 days of daily diary data. We used a three-level generalized linear mixed model (GLMM) approach estimating zero-inflated Conway-Maxwell Poisson regressions to assess the effect of weekend and specific weekend day on number of overall drinks, number of pregaming drinks, and negative alcohol-related consequences. Proportions tests assessed for differences in any cannabis use and daily co-use between Halloweekend and non-Halloween weekends.

RESULTS

Zero-inflated portions of the GLMMs indicated that general drinking, pregaming, and negative consequences were most prevalent on Halloweekend and Fridays and Saturdays. Count portions of the models indicated that general drinking quantity was highest during these periods, and participants experienced a greater number of negative consequences on Halloweekend compared with the weekend before; no differences were observed in the quantity of pregaming drinks consumed across weekends or days. No significant differences in cannabis use or co-use were observed between weekends.

CONCLUSIONS

Given risk associated with Halloweekend compared with weekends immediately before and after, interventions targeting alcohol use and pregaming on Halloweekend may be beneficial to reduce related harm for heavy-drinking students.

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

OBJECTIVE

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND AND OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

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

Acute Consequences Associated With Co-use of Alcohol and Cannabis: A Daily Survey Analysis

OBJECTIVE

Co-use of alcohol and cannabis has been associated with more total negative consequences than single-substance use, but results have been mixed depending on whether the single substance was alcohol or cannabis. The present study used within-person analyses to examine whether co-use increased the risk for experiencing specific acute negative consequences.

METHOD

College students who were co-users of alcohol and cannabis (N = 341; M age = 19.8 years; 51.3% female; 74.8% White) completed 56 days of five daily surveys across two bursts. We used generalized linear mixed effects models to examine the effects of type of substance use day on specific negative consequences, controlling for consumption and covariates.

RESULTS

Relative to both alcohol-only and co-use days, cannabis-only days were associated with decreased likelihood of experiencing hangover, blackout, nausea/vomiting, injury, rude/aggressive behavior, and unwanted sex. Relative to alcohol-only days, cannabis-only and co-use days were associated with an increased likelihood of driving high/drunk. Finally, there was an increased likelihood of hangovers on alcohol-only days compared with co-use days.

CONCLUSIONS

Days with different types of substance use differed in specific consequences. Most of the negative co-use consequences investigated here appear to be driven by alcohol consumption rather than cannabis use. The results also indicated that these young adults were more likely to endorse driving under the influence of cannabis than alcohol. Interventions for co-use should target alcohol consumption to reduce negative consequences such as blackout, injury, rude/aggressive behavior, and unwanted sex and highlight the dangers of driving under the influence of cannabis.

Characteristics of drinking episodes associated with simultaneous alcohol and cannabis use among underage drinkers in the United States

BACKGROUND

Simultaneous alcohol and cannabis (SAC) use is associated with more negative consequences than independent use of alcohol or cannabis. Contextual characteristics of drinking episodes are associated with the quantity of alcohol consumed and related risk. This study examined whether drinking contexts may also be associated with SAC use.

METHODS

National Survey on Drug Use and Health (NSDUH) 2010-2019 data from past 30-day drinkers aged 12-20 (n = 39,456) were used. A weighted multivariable logistic regression model examined associations between contextual characteristics (alcohol source, number of people, drinking location) and SAC use during their most recent drinking occasion. Models adjusted for survey year, heavy episodic drinking, age, sex, race/ethnicity, student status, and metropolitan area status.

RESULTS

More than one-in-five drinkers reported SAC use. Compared to getting alcohol from parents/family, those who took it from a home (OR = 1.51,95 %CI = 1.24,1.84), got it for free another way (OR = 2.30,95 %CI = 2.05,2.59), paid someone else for it (OR = 2.83,95 %CI = 2.46,3.25), or purchased it themselves (OR = 3.12,95 %CI = 2.66,3.67) had higher odds of SAC use. Compared to drinking alone, drinking with more than one person was associated with higher odds of SAC use (OR = 1.36,95 %CI = 1.12,1.66). Compared to drinking in their home, drinking in a bar (OR = 0.51,95 %CI = 0.41,0.64) had lower odds of SAC use, whereas drinking in someone else's home (OR = 1.12,95 %CI = 1.02,1.22), a car (OR = 1.36,95 %CI = 1.04,1.77), or multiple locations (OR = 1.29,95 %CI = 1.09,1.53) had higher odds of SAC use.

CONCLUSIONS

Findings suggest that alcohol-related contextual characteristics are associated with SAC use among underage drinkers. Laws addressing underage alcohol consumption, including social host liability and sales to minors laws, may also decrease simultaneous cannabis use.

Past year high-intensity drinking moderates the association between simultaneous alcohol and marijuana use and blackout frequency among college students

Objective: The role of simultaneous alcohol and marijuana (SAM) use in the experience of blackouts among college students is unclear. To clarify discrepancies, the current study evaluated whether the association between SAM user status and blackouts was moderated by high-intensity drinking (HID). Participants and Methods: College students (N = 1,224; 63.7% female) reported on their past year experiences of blackout, marijuana use, SAM use, and HID (i.e., drinking at least twice the binge threshold). Results: SAM users had more past year blackouts than non-SAM users, but this effect was only significant among SAM users who had engaged in HID in the past year (nonbinge: F(5,37) = 0.50, p = 0.49; binge: F(5,138) = 0.23, p = 0.63; HID: F(5,328) = 4.52, p = 0.03). Conclusions: Effects of SAM user status on the experience of alcohol-related blackouts may be limited to individuals who engage in HID.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

What Predicts Willingness to Experience Negative Consequences in College Student Drinkers?

OBJECTIVE

Research has shown that students who were more willing to experience consequences reported higher rates of alcohol consumption and negative consequences. The present study used a longitudinal design to examine intra- and interpersonal consequence-specific predictors of willingness to experience negative consequences.

METHOD

Students (N = 2,024) were assessed in the fall (Time [T] 1) and spring (T2) semesters of their first year in college. Intrapersonal constructs (i.e., expectancies, subjective evaluations, self-efficacy), interpersonal constructs (i.e., peer descriptive, injunctive norms), and personality constructs (i.e., self-regulation, impulsivity, sensation seeking) were assessed at T1 and willingness to experience negative alcohol-related consequences was assessed 6 months later. A structural path model examined the relationship between T1 predictors and T2 willingness. T1 drinking and sex were included as covariates.

RESULTS

These results demonstrated significant positive relationships between T1 participants' subjective evaluations of consequences, expectancies of experiencing consequences, and T2 willingness to experience negative consequences. Further, impulsivity, sensation seeking, and T1 drinking showed significant, positive associations with willingness, whereas higher self-regulation was significantly associated with lower willingness. Men were significantly more willing to experience negative consequences than women. No significant associations were observed between normative perceptions and willingness.

CONCLUSIONS

Intrapersonal and personality constructs, as well as previous drinking, were significantly associated with willingness to experience consequences whereas interpersonal constructs were not. Men were significantly more willing to experience negative consequences. College student interventions may benefit from focusing on significant constructs identified in the current study (e.g., enhancing self-regulation) and focusing on students with higher willingness to experience negative consequences.

Simultaneous alcohol and marijuana use among college students in the United States, 2006-2019

•

US college students’ simultaneous alcohol and marijuana (SAM) use rate was rising.

•

There was an upward trend of SAM use among Black college students (2006–2019).

•

Hispanic and Asian American/Pacific Islander students’ trend remained stable.

Objective

Simultaneous alcohol and marijuana (SAM) use exposes college students to a myriad of adverse consequences. However, there is no recent nationally representative study on SAM use among college students in the United States (US). To provide an update to the literature, the present study aimed to examine the trends, prevalence, and correlates of SAM use among US college students between 2006 and 2019, using nationally representative data.

Method

We used data from the 2006–2019 National Survey on Drug Use and Health (NSDUH) and the analytic sample was limited to the 55,669 full-time college student respondents (ages 18–22). Using logistic regression analysis, we assessed trends in SAM use prevalence and examined sociodemographic and psycho-social-behavioral correlates of SAM use.

Results

The proportion of US college students who reported SAM use increased significantly from 8.13% (2006–2010) to 8.44% (2015–2019). However, examination by race/ethnicity revealed that the increasing trend was largely driven by Black college students, whose SAM use prevalence increased significantly from 5.50% (2006–2010) to 9.30% (2015–2019), reflecting a 69.09% increase. SAM use rates did not change significantly among other racial/ethnic groups.

Conclusions

This study uncovered an upward trend and prevalence of SAM use among US college students, calling for more research and public health interventions in this area. At-risk subgroups that warrant more attention include college students who are Black, female, above the legal drinking age, have a lower than $20,000 household income, and reside in small metropolitan areas.

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

BACKGROUND

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

OBJECTIVES

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

ELIGIBILITY CRITERIA

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

SOURCES OF EVIDENCE

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

CHARTING METHODS

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

RESULTS

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

CONCLUSIONS

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

Self-reported perceived negative consequences of marijuana use among U.S. young adult users, 2008-2019

PURPOSE

This study estimated self-reported perceived negative marijuana use consequences among a national sample of U.S. young adults, examining consequence prevalence differences by use frequency, college attendance, living situation, employment, sex, and race/ethnicity; and use frequency/sociodemographic characteristic interactions.

METHODS

A subsample of 1,212 respondents from the 2004-2018 class cohorts of 12th grade students participating in the nationally-representative Monitoring the Future study was surveyed up to two times from modal ages 19 through 22 (in 2008-2019). Respondents self-reported negative consequences related to their own past 12-month marijuana use. Bivariate and multivariable models examined subgroup differences in consequence prevalence.

RESULTS

Approximately 60% of those using frequently (20+ use occasions in the past 30 days) and 35% of those using non-frequently reported negative consequences. Among all young adult marijuana users, 31.1% reported emotional/physical consequences, 12.9% performance/financial consequences, and 12.3% relational consequences. Use frequency was positively associated with consequence likelihood, excluding regret and unsafe driving. Among college students, frequent use was more strongly associated with any and performance/financial consequences. Controlling for use frequency, men reported more performance/financial consequences; relational consequences were higher among Hispanic (vs. White) respondents, and those living with parents, employed full-time, and not attending 4-year colleges.

CONCLUSION

Young adults using marijuana reported a wide range of negative use consequences; likelihood of most consequences increased with higher use frequency. Perceived consequences varied by college attendance, living situation, employment, sex, and race/ethnicity. Efforts to reduce negative marijuana consequences may be strengthened by recognizing and addressing the different types of negative consequences users perceive.

Stress and Affect as Daily Risk Factors for Substance Use Patterns: an Application of Latent Class Analysis for Daily Diary Data

At the population level, use of multiple substances (or "co-use") is prevalent in young adulthood and linked with increased risk for experiencing substance-related harms. Less understood is the heterogeneity of substance use behaviors within individuals and across days, as well as the proximal predictors of these daily use patterns. The present study applied latent class analysis to daily diary data to identify daily substance use patterns and compare day-level class membership based on day-level stress and positive and negative affect among a higher-risk sample of young adult substance users. Participants (n = 152) completed up to 13 daily assessments of stress, affect, and substance use behavior. Among substance use days, five classes of days were identified: cannabis (some alcohol; 43% of days), alcohol-only (26%), vaping (some alcohol, cannabis; 24%), stimulant + alcohol (some cannabis, vaping; 4%), and cigarette-only (3%) days. Days with lower levels of perceived stress were significantly more likely to be alcohol-only Days relative to being days characterized by cigarette use, cannabis use, or multiple drug combinations. Days with higher levels of stress and negative affect were more likely to be cigarette-only days relative to cannabis and vaping days. Study findings document the wide range of substance use and co-use behaviors exhibited among young adults in daily life and highlight the importance of considering risk factors that correspond to days of problematic use patterns.

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

OBJECTIVE

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

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

OBJECTIVE

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

METHOD

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

RESULTS

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

CONCLUSION

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

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

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

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

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

Retail Availability of Recreational Marijuana and Alcohol in Oregon Counties and Co-Use of Alcohol and Marijuana and Related Beliefs among Adolescents

Objective: We investigated whether recreational marijuana legalization (RML) in Oregon in 2015 and recreational marijuana and alcohol retail outlet density levels in Oregon counties were associated with increased alcohol and marijuana co-use and beliefs supportive of alcohol and marijuana use among adolescents. Method: We conducted secondary analyses of biennial data collected from 11th graders who participated in the Student Wellness Survey (SWS) in 36 Oregon counties from 2010 to 2018 (N = 71,870). Multi-level logistic regression analyses assessed changes in past-30-day co-use of alcohol and marijuana, and alcohol- and marijuana-related beliefs after RML in counties with low, medium, and high densities of licensed recreational marijuana and alcohol retail outlets. We used post-RML 2016 and 2018 SWS data to examine whether beliefs accounted for any relationship of recreational marijuana and alcohol outlet density with alcohol and marijuana co-use. Results: We found a significant post-RML increase in past-30-day alcohol and marijuana co-use in 2016 in counties with the highest density of recreational marijuana and alcohol retail outlets. There were significant post-RML increases in perceived risk and parent approval of alcohol and marijuana use. Analyses with 2016 and 2018 SWS data indicated that the relationship between level of recreational marijuana and alcohol retail outlet density and past-30-day alcohol and marijuana co-use was accounted for beliefs about marijuana and alcohol availability, approval by parents, and risk. Conclusion: RML and greater retail availability of recreational marijuana and alcohol were positively associated with alcohol and marijuana co-use among adolescents, and with beliefs favorable to alcohol and marijuana use.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The Prospective Effects of Parents' and Friends' Approval of Drinking on Simultaneous Alcohol and Marijuana Use during College

Background: Recent reports indicate that simultaneous alcohol and marijuana (SAM) use is a growing health concern among college students. As SAM use consists of both alcohol and marijuana, risk factors associated with either can serve as plausible targets by prevention efforts to reduce SAM use. Objectives: To explore this, the current study investigated the direct and indirect effects of two established risk factors for drinking on SAM use: perceived parental permissiveness toward drinking and friends' approval toward drinking (injunctive norms). Method: Incoming first-year students (N = 470) reported parental permissiveness, injunctive norms, alcohol use, and SAM use at baseline (T1) and 5 months later (T2). SAM use was assessed again 15 months post-baseline (T3). Path analysis was conducted to examine whether T2 variables mediated relationships between T1 variables and T3 SAM use. Results: Results revealed that T2 student alcohol use mediated the effects of T1 parental permissiveness, injunctive norms, and alcohol use on T3 SAM use. Conclusions/Importance: Findings from this study extend research on SAM use by identifying perceived parental permissiveness and injunctive drinking norms as risk factors for SAM use through their effects on alcohol use. Based on these findings, it is plausible that parent-based interventions and interventions targeting peer injunctive norms during the first year of college could be used to effectively prevent or reduce SAM use.

Motivations to combine alcohol and nicotine in college students: A validation of the Alcohol and Nicotine Motives Scale

INTRODUCTION

Research on combining alcohol and nicotine (ALCNIC) has shown this risky behavior results in significantly more consequences than using either alcohol or nicotine alone. No measures currently exist to assess ALCNIC motives limiting intervention and prevention efforts. The present study developed a psychometrically sound and multidimensional measure of ALCNIC motives (the ANMS).

METHODS

An initial item pool of ALCNIC items was developed from literature on college student drinking, focus groups, and individual interviews. Study 1 involved students from a northeastern university who completed an online survey on the ALCNIC items (N = 55; 57.1% female; Mage = 20.3). Analysis focused on reliability (exploratory factor analysis). Study 2 involved a cross-validation national sample of college students (N = 336; 49.7% female; Mage = 21.2) completing the same survey items. Confirmatory factor analysis, criterion-related validity (ALCNIC/weekend drinking), and discriminant validity (social desirability) were assessed using structural equation modeling.

RESULTS

Results across two studies revealed three factors to engage in ALCNIC: antagonistic (party longer), synergistic (enhanced effects), and social (peer pressure); and one factor to avoid ALCNIC: negative effects (feeling anxious) (all alphas > 0.7). In study 2, criterion-related validity revealed that synergistic motives were significantly positively associated with ALCNIC use; and negative effects motives were significantly negatively associated with ALCNIC use. Discriminant validity showed ALCNIC subscales were not significantly associated with social desirability (except social).

CONCLUSIONS

The study developed a reliable and valid measure of motives for ALCNIC use. Results were robust to cross-validation across two samples of college students. These measures provide targets for intervention and prevention efforts.

Characterizing symptoms of cannabis use disorder in a sample of college students

Since legalization of marijuana in several U.S. states in 2012, there has been concern about increases in the development of cannabis use disorder (CUD). The current study examined rates of CUD in Colorado college students who reported regular marijuana use and assessed a range of factors associated with CUD symptoms, including coping motives, concentrate/dab use, mental health concerns (depression, anxiety), age of regular marijuana use, and alcohol use. College students were recruited from a mid-sized university and completed a baseline assessment that included a marijuana urine screen. Participants reported a median of five CUD symptoms and 90% met criteria for CUD. After adjusting for covariates, age of regular marijuana use was negatively associated with number of CUD symptoms, while average daily alcohol drinks was positively associated with number of symptoms. Prevention and intervention efforts at the university level should be increased to reduce negative outcomes associated with problem marijuana use.

Alcohol and marijuana co-use: Consequences, subjective intoxication, and the operationalization of simultaneous use

BACKGROUND

Alcohol and marijuana are frequently co-used with overlapping effects. However, the absence of consistent operational definitions delineating simultaneous alcohol and marijuana use (SAM) from concurrent use (CAM) challenges consistent inferences about these behaviors. This study first examined whether daily alcohol and marijuana co-use predicted substance-use related consequences and subjective intoxication; and then evaluated whether competing operationalizations of SAM and CAM were associated with differences in these outcomes on co-use days.

METHODS

A sample of 341 young adult college students who reported past-month use of both alcohol and marijuana "at the same time so that their effects overlapped" completed a two-wave survey with paired 28-day daily experience sampling bursts examining alcohol and marijuana co-use. Outcomes were (a) daily substance-use related consequences; and (b) daily subjective intoxication. Focal predictors were daily drinks and marijuana uses; daily co-use versus single-substance use (Aim 1) or CAM versus SAM (Aim 2); and their interaction.

RESULTS

Participants reported more negative consequences on co-use days versus marijuana-only days and greater subjective intoxication relative to alcohol or marijuana-only days. Competing operationalizations of SAM, defined as daily co-use occurring within 1-240 min in increments of 1 min, found no difference in consequences or subjective intoxication regardless of operationalization.

CONCLUSION

Co-use days involve greater risk than alcohol-only or marijuana-only days. Although there was no evidence of additional daily risk from simultaneous use regardless of the timeframe used to operationalize it, investigating these effects remains challenging due to the generally small timeframe between substances on co-use days in this sample.

Inclusion of Cannabis Users in Alcohol Research Samples: Screening In, Screening Out, and Implications

BACKGROUND

Alcohol and cannabis are frequently co-used, as 20-50% of those who drink alcohol report co-using cannabis. This study is based on the argument that alcohol researchers should enroll cannabis users in human laboratory studies of alcohol use disorder (AUD) to strengthen generalizability. This study examines how heavy drinking cannabis users differ from non-cannabis using heavy drinkers.

METHODS

In a community sample of non-treatment-seeking heavy drinkers (n = 551, 35% female), cannabis users were identified through: (a) self-reported cannabis use in the past 6 months and (b) positive urine toxicology test for tetrahydrocannabinol (THC). Cannabis users, identified as described previously, were compared with non-cannabis users on demographic and clinical characteristics.

RESULTS

Those who endorsed cannabis use in the past 6 months reported more binge drinking days. Participants who tested positive for THC had higher Alcohol Use Disorder Identification Test scores and more binge drinking days. Younger age and being a tobacco smoker were associated with an increased likelihood of cannabis use in the past 6 months, whereas male gender and being a tobacco use were associated with a greater likelihood of testing positive for THC. Individuals with cannabis use disorder (CUD) endorsed more depression and anxiety and had higher AUD symptom counts than cannabis users without CUD.

CONCLUSIONS

The inclusion of cannabis users in AUD samples allows for increased clinical severity. Excluding cannabis users from AUD studies may limit representativeness and expend unnecessary study resources. Lastly, tobacco use may explain a large portion of the effects of cannabis use on sample characteristics.

SHORT SUMMARY

Alcohol and cannabis are frequently co-used substances. In a sample of non-treatment-seeking heavy drinkers (n = 551, 35% female), cannabis users reported higher alcohol use and higher likelihood of tobacco use than non-cannabis users. Including cannabis users in alcohol research studies will improve representativeness and likely increase clinical severity.

Cross-fading motives for simultaneous alcohol and marijuana use: Associations with young adults' use and consequences across days

BACKGROUND

Many young adults engage in simultaneous alcohol and marijuana (SAM) use so that their effects overlap. Little is known about motivations for dual substance use and associations with use and consequences. This study examined daily-level associations between cross-fading motives and levels of alcohol and marijuana use and consequences.

METHODS

Young adults who reported SAM use in the month prior were surveyed in two 14-day bursts. Data included 1049 SAM use days from 281 young adults (age 18-25; M age = 21.80, SD = 2.16; 50 % women). Multilevel models assessed between- and within-person effects of cross-fading motives (i.e., to enhance the effects of marijuana and/or alcohol use by using them simultaneously) on alcohol and marijuana use and consequences, after adjusting for general enhancement, social, coping, and conformity motives and the amount of alcohol and marijuana used that day.

RESULTS

On 76 % of SAM use days, participants endorsed cross-fading motives (i.e., to enhance the effect of alcohol or marijuana or to get drunk and high at the same time). Having stronger cross-fading motives was associated with greater alcohol use, perceived intoxication, and positive alcohol consequences at the between- and within-person levels. In addition, between-person, individuals who reported stronger cross-fading motives on average reported more negative alcohol consequences and positive marijuana consequences on average. Cross-fading motives on a given day were not associated with marijuana use or marijuana consequences that day.

CONCLUSIONS

Cross-fading motives were common and varied from day to day. Understanding the motivational context for dual substance use may support future interventions for cross-fading.

Does Cannabis Use Predict More Severe Types of Alcohol Consequences? Longitudinal Associations in a 3-Year Study of College Students

BACKGROUND

Prior research shows that negative drinking outcomes among young adults may be exacerbated by cannabis use. However, to date, there have been few longitudinal studies of associations between cannabis use and negative alcohol-related consequences. This study examined longitudinal within-person associations between cannabis use and several domains of negative alcohol consequences among young adults and explored the moderating role of sex.

METHOD

We analyzed data from N = 997 students assessed 4 times per year over the first 3 years of university. At each time point, participants completed measures of past-month cannabis use frequency, typical weekly number of drinks, and 8 domains of negative alcohol consequences. Longitudinal associations were examined in multilevel models.

RESULTS

Within-person changes in frequency of cannabis use were not uniquely associated with changes in total alcohol consequences aggregated across several alcohol consequence domains. However, when examining alcohol consequence domains separately, within-person increases in cannabis use frequency were specifically associated with increases in some (but not all) of the more severe types of alcohol consequences, including risky behaviors, poor self-care, and alcohol dependence symptoms. No support was observed for the moderating role of sex in the longitudinal within-person associations between cannabis use and alcohol consequence domains.

CONCLUSIONS

Findings suggest that within-person changes in cannabis use frequency among young adults are associated with corresponding changes in some domains of alcohol consequences (but not others) when examined over the course of several years. Results may inform targeted harm reduction interventions for young adult drinkers who use cannabis, although future research is needed to clarify the mechanisms of the observed associations.

Consequences of alcohol and marijuana use among college students: Prevalence rates and attributions to substance-specific versus simultaneous use

College students who use alcohol and marijuana often use them simultaneously, so that their effects overlap. The present study examined whether negative consequences experienced by simultaneous alcohol and marijuana (SAM) users vary from those experienced by individuals who use alcohol and marijuana concurrently but not simultaneously (CAM) or single-substance users. We considered 9 types of consequences: cognitive, blackout, vomiting, academic/occupational, social, self-care, physical dependence, risky behaviors, and driving under the influence (DUI). Further, we examined whether consequences experienced by SAM users are attributed to using alcohol, marijuana, or both simultaneously. The sample included past-year alcohol and marijuana users age 18-24 (N = 1,390; 62% female; 69% White; 12% Hispanic) recruited from 3 U.S. college campuses. SAM users experienced a greater overall number of consequences than CAM or alcohol-only users, even controlling for frequency and intensity of alcohol and marijuana use and potentially confounding psychosocial and sociodemographic factors. Experiencing specific consequences differed between simultaneous and concurrent users, but after adjusting for consumption and other covariates, only blackouts differed. In contrast, SAM users were more likely to experience each consequence than alcohol-only users, with strongest effects for DUI, blackouts, and cognitive consequences. Among SAM users, consequences were most likely to be attributed to alcohol and were rarely attributed to simultaneous use. Being a user of both alcohol and marijuana and using alcohol and marijuana together so that their effects overlap each contribute to risk, suggesting there is value in targeting the mechanisms underlying type of user as well as those underlying type of use. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

A Daily Study Comparing Alcohol-Related Positive and Negative Consequences for Days With Only Alcohol Use Versus Days With Simultaneous Alcohol and Marijuana Use in a Community Sample of Young Adults

BACKGROUND

Alcohol and marijuana are psychoactive substances commonly used by young adults and are independently associated with numerous acute and long-term consequences. Many young adults engage in simultaneous alcohol and marijuana (SAM) use to cross-fade (i.e., to enhance the effects of intoxication), although the extent to which alcohol use and alcohol-related consequences increase on SAM occasions compared to alcohol-only occasions is unclear. This study examines daily data among a sample of SAM users comparing SAM days to other days when young adults only used alcohol.

METHODS

A sample of 409 young adults (age 18 to 25; M_age  = 21.6, SD = 2.2; 50.9% women) who reported SAM use in the past month completed 2 bursts of 14 days of daily surveys (28 days in total) assessing alcohol use, alcohol-related consequences, and SAM use.

RESULTS

Multilevel models based on alcohol-only and SAM days (n = 3,016 days; 391 individuals) indicated young adults drank more alcohol on SAM days compared to alcohol-only days (with no marijuana use). Similarly, days with SAM use were associated with more alcohol-related positive and negative consequences. The daily association between SAM use and positive consequences was statistically significant, after accounting for the amount of alcohol consumed; in contrast, the association between SAM use and negative consequences was diminished and nonsignificant.

CONCLUSIONS

Among young adult SAM users, days with SAM use were associated with more alcohol use and positive consequences compared to days they only drank alcohol. Further examination of the motivational context for engaging in SAM use, as well as potential physiological interactions between alcohol and marijuana use on alcohol's effects, is warranted. Alcohol interventions might benefit from addressing increased alcohol use and alcohol-related consequences as risks associated with SAM use.

Simultaneous alcohol and marijuana use in daily life: Implications for level of use, subjective intoxication, and positive and negative consequences

Simultaneous alcohol and marijuana (SAM) use is prevalent among young adult drinkers and associated with increased risk for harms. Less understood about SAM use is whether increased risk is incurred on SAM use occasions relative to occasions in which individuals used only 1 substance. From a sample of young adult SAM users, we compared occasions in which individuals simultaneously used alcohol and marijuana so that the effects overlapped ("SAM days"), occasions involving only alcohol ("alcohol days"), and occasions involving only marijuana ("marijuana days") on level of use, level of subjective intoxication, and negative and positive consequences. Eligible participants (N = 154; 57.8% female, 72.7% non-Hispanic/Latinx White) were 18-25 years old, reported past-month SAM use, and reported past 2-week binge drinking. Participants completed up to 14 daily assessments on their substance use behavior. Multilevel models indicated that, relative to alcohol days, SAM days had more negative consequences. SAM and alcohol days were not statistically different on level of use, level of subjective alcohol intoxication, or positive consequences. Relative to marijuana days, SAM days had more negative consequences and more positive consequences. Level of use (number of hits) and level of marijuana intoxication were not statistically different. In addition to SAM users being a more at-risk group, SAM occasions are associated with greater risk within this vulnerable population. Fine-grained ecological momentary assessments are needed to better understand perceptions and behavior throughout a SAM use episode. (PsycInfo Database Record (c) 2020 APA, all rights reserved).