Daily-level effects of alcohol, marijuana, and simultaneous use on young adults' perceived sleep health

Alcohol use disorder as a moderator of the relationship between posttraumatic stress disorder and suicidality among military personnel

BACKGROUND

Alcohol use disorder (AUD), posttraumatic stress disorder (PTSD), and suicide are substantial public health concerns among military service members, yet the nature of their relationships is not well understood. Here, we tested the hypothesis that AUD moderates the relationship between PTSD symptom severity and suicidal ideation.

METHODS

This secondary analysis uses data collected at baseline for a randomized clinical trial. The sample consists of 160 active-duty service members from three service branches (Army, Air Force, and Navy). All participants met diagnostic criteria for PTSD and were not engaged in evidence-based PTSD treatment at the time of enrollment. Zero-inflated Poisson generalized linear regression models were used to test the associations of PTSD and AUD symptom severity with the presence and severity of suicidal ideation.

RESULTS

Findings suggest that AUD symptom severity moderates (i.e., amplifies) the relationship between PTSD symptoms and severity of suicidal ideation among military personnel with untreated PTSD. Among service members with mild or absent AUD, we found no significant association between PTSD symptoms and the severity of suicidal ideation. However, when AUD severity was average (i.e., sample mean) or high (mean + 1SD), PTSD symptoms were significantly positively associated with the severity of suicidal ideation.

CONCLUSIONS

This study highlights the importance of assessing AUD and PTSD as a part of suicide risk evaluations of veterans. The results also provide strong support for the maintenance and further development in the military health system of treatment programs that simultaneously address AUD and PTSD comorbidity.

Sleep-Related Predictors of Risk for Alcohol Use and Related Problems in Adolescents and Young Adults

PURPOSE

Growing evidence supports sleep and circadian rhythms as influencing alcohol use and the course of alcohol use disorder (AUD). Studying sleep/circadian-alcohol associations during adolescence and young adulthood may be valuable for identifying sleep/circadian-related approaches to preventing and/or treating AUD. This paper reviews current evidence for prospective associations between sleep/circadian factors and alcohol involvement during adolescence and young adulthood with an emphasis on the effects of sleep/circadian factors on alcohol use.

SEARCH METHODS

The authors conducted a literature search in PsycInfo, PubMed, and Web of Science using the search terms "sleep" and "alcohol" paired with "adolescent" or "adolescence" or "young adult" or "emerging adult," focusing on the title/abstract fields, and restricting to English-language articles. Next, the search was narrowed to articles with a prospective/longitudinal or experimental design, a sleep-related measure as a predictor, an alcohol-related measure as an outcome, and confirming a primarily adolescent and/or young adult sample. This step was completed by a joint review of candidate article abstracts by two of the authors.

SEARCH RESULTS

The initial search resulted in 720 articles. After review of the abstracts, the list was narrowed to 27 articles reporting on observational longitudinal studies and three articles reporting on intervention trials. Noted for potential inclusion were 35 additional articles that reported on studies with alcohol-related predictors and sleep-related outcomes, and/or reported on candidate moderators or mediators of sleep-alcohol associations. Additional articles were identified via review of relevant article reference lists and prior exposure based on the authors' previous work in this area.

DISCUSSION AND CONCLUSIONS

Overall, the review supports a range of sleep/circadian characteristics during adolescence and young adulthood predicting the development of alcohol use and/or alcohol-related problems. Although sleep treatment studies in adolescents and young adults engaging in regular and/or heavy drinking show that sleep can be improved in those individuals, as well as potentially reducing alcohol craving and alcohol-related consequences, no studies in any age group have yet demonstrated that improving sleep reduces drinking behavior. Notable limitations include relatively few longitudinal studies and only two experimental studies, insufficient consideration of different assessment timescales (e.g., day-to-day vs. years), insufficient consideration of the multidimensional nature of sleep, a paucity of objective measures of sleep and circadian rhythms, and insufficient consideration of how demographic variables may influence sleep/circadian-alcohol associations. Examining such moderators, particularly those related to minoritized identities, as well as further investigation of putative mechanistic pathways linking sleep/circadian characteristics to alcohol outcomes, are important next steps.

Daily diary study of associations between alcohol, cannabis, co-use and sleep quality in individuals with intentions to use cannabis to cope with anxiety

INTRODUCTION

Sleep problems and anxiety conditions are common comorbidities and may be influenced by cannabis and alcohol use. This study examined daily within-person variation in subjective sleep quality among individuals with anxiety symptoms after cannabis or alcohol were used alone, and after co-use.

METHODS

A total of 347 individuals with intentions to use cannabis to cope with anxiety reported their cannabis and alcohol use in the previous 24 h and their previous nights' sleep quality for 30 consecutive days. Mixed-effects models examined whether the within-person daily variation in use of cannabis and alcohol (alone and co-use) was associated with subjective sleep quality. Models also examined whether daily cannabis and alcohol use associations with sleep were moderated by frequency of cannabis, alcohol and co-use during the study period.

RESULTS

Compared to non-use, participants reported better sleep after cannabis-use-only and after co-use, but not after alcohol-use-only. People who more frequently use alcohol and cannabis reported sleeping better after cannabis-use-only days compared to those who use cannabis and alcohol less frequently.

DISCUSSION AND CONCLUSIONS

The study's utilisation of naturalistic data among individuals with anxiety symptoms replicated previously reported experimental findings among individuals without sleep and anxiety problems that overall, cannabis is associated with higher subjective sleep quality. The results expand upon other research to suggest that more frequent use of alcohol and cannabis may moderate daily associations of cannabis use and sleep, potentially through pharmacokinetics and cross-sensitisation.

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

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

Mapping insomnia symptoms and circadian preferences to mental health problems in men and women across the lifespan

This study identified subgroups in the general population based on combinations in three night-time insomnia symptoms and four dimensions of circadian preferences ("sleep profiles") and investigated the associations between sleep profiles and nine common mental health problems. The data came from the Lifelines cohort add-on study "Comorbid Conditions of ADHD" and included 37,716 individuals (aged 4-91 years) from the Dutch general population who completed a digital survey. Latent profile analysis was used to identify sleep profiles in twelve age-sex subgroups. Linear regression was used to investigate whether sleep profiles differ in mental health problems. Participants were classified into three sleep profiles: "Healthy Larks", who had early circadian preferences and no insomnia symptoms; "Sleepy Owls" with late circadian preferences and nonrestorative sleep; and "Sleepless Doves" with intermediate circadian preferences and severe insomnia symptoms. Compared to "Healthy Larks", all mental health problems were significantly more severe in "Sleepy Owls" and even worse in "Sleepless Doves". These associations were similar in men and women but weakened with age. However, "Sleepy Owls" and "Sleepless Doves" did not differ in heavy alcohol drinking, drug use, and smoking. Our findings strengthened the evidence for the universal role of healthy sleep in mental wellbeing.

Cannabis use and sleep disturbances among White, Black, and Latino adults in the United States: A cross-sectional study of National Comorbidity Survey-Replication (2001-2003) data

OBJECTIVE

Research investigating cannabis use and sleep health is limited, and results are mixed. Few studies were nationally representative with racially-ethnically diverse samples or assessed potential modifiers. Our objective was to investigate cross-sectional associations between reported cannabis use and sleep disturbances by potential modifiers among non-Hispanic White, non-Hispanic Black, and Hispanic/Latino men and women in the United States.

METHODS

We used nationally representative National Comorbidity Survey-Replication data collected from 2001 to 2003 among 3929 adults. Poisson regression with robust variance estimated prevalence ratios (PR) and 95% confidence intervals of patterns of sleep disturbances identified through latent class analysis. Models adjusted for sociodemographic, health behavior, and clinical characteristics were stratified by race-ethnicity and by race-ethnicity along with sex/gender, and age, separately.

RESULTS

Over half of adults reported cannabis use (52%-ever/lifetime vs 48%-never). We identified two latent classes: multiple sleep disturbances with daytime sleepiness and no sleep disturbances with some daytime sleepiness. Prevalence of multiple sleep disturbances with daytime sleepiness was higher among participants reporting lifetime cannabis use (23% vs 20%). Associations did not vary by race-ethnicity or sex/gender. Lifetime vs never cannabis use was marginally associated with a higher prevalence of multiple sleep disturbances with daytime sleepiness only among adults aged 25-29years (PR=1.09 [95% confidence interval: 1.00-1.18]; eg, PRage 40+ years=1.00 [0.97-1.03], pinteraction=0.03).

CONCLUSIONS

Associations between cannabis use and sleep may vary by age. Replication with more recent data and prospective studies that investigate intersectional identities among diverse populations with objective assessments are warranted.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Longitudinal examination of high-risk drinking contexts: Daytime drinking, pregaming, and drinking games linked to high-risk alcohol use and negative consequences in young adults

BACKGROUND

The contexts in which young adults drink alcohol play a salient role in alcohol-related outcomes and negative consequences at an event-level, but less is known about longitudinal risks. We collected longitudinal monthly data across 2 years on (a) daytime drinking, (b) pregaming/pre-partying, and (c) playing drinking games. We then examined associations between drinking in these contexts and within-person variability in alcohol consumption, consequences, and simultaneous alcohol and marijuana (SAM) use in a given month. We also examined the extent to which drinking in these contexts predicted hazardous drinking (using Alcohol Use Disorders Identification Test (AUDIT) scores) at a distal follow-up timepoint, controlling for baseline AUDIT scores.

METHOD

A community sample of 759 young adults (Mage  = 21.1 years; 56.4% female) completed monthly surveys for 24 consecutive months and a distal 30-month follow-up. Multilevel models estimated within- and between-person associations between drinking context frequencies (daytime drinking, pregaming, drinking games) and alcohol-related outcomes (weekly consumption, consequences, SAM use). A single-level negative binomial regression tested associations between drinking context frequency averages across a two-year period and changes in AUDIT scores from baseline to a follow-up 2.5 years later.

RESULTS

Over 75% of the sample of non-abstaining young adults reported drinking in each of the three contexts at least once during the 24-month period. Within-persons, young adults reported greater consumption, more negative consequences, and increased likelihood of SAM use during months that they drank in these contexts more often than usual. Each context was associated with negative consequences, even when controlling for alcohol use frequency. More frequent daytime drinking and pregaming, but not drinking games, were associated with increases in AUDIT scores at the 30-month follow-up, suggesting that there are potential long-term risks of drinking in these contexts.

CONCLUSIONS

Findings suggest that daytime drinking, pregaming, and playing drinking games are high-risk contexts in terms of month-to-month and long-term risks. Additional research is needed on the various contexts in which young adults drink alcohol and the extent to which contextual factors interact with one another to amplify/reduce risks and harms.

Leveraging Ecological Momentary Assessment to Examine Bi-directional Associations Between Sleep Quality, Adolescent/Young Adult Alcohol Craving and Use

BACKGROUND

Alcohol use is common among adolescents and young adults (AYA) and linked to poor sleep quality. Poor sleep quality may also increase alcohol use and alcohol craving, yet bi-directional relations between sleep quality and AYA alcohol use are poorly understood.

PURPOSE

This study examined bi-directional associations between sleep quality, alcohol craving, and alcohol use in AYA using ecological momentary assessment (EMA) and explored if biological sex, age, or race moderated these associations.

METHODS

This pre-registered secondary analysis pooled EMA data from the baseline, pre-randomization period (M = 8.18 days, range = 1-17) in two double-blind randomized placebo-controlled clinical trials examining medication effects on alcohol use in AYA (N = 115). Each morning, participants reported sleep quality and alcohol consumption (i.e., number of standard drinks) from the previous day, and craving was rated at several random points each day.

RESULTS

Multilevel modeling showed that poorer average sleep quality was associated with higher levels of alcohol craving for females but not for males, and better overall levels of sleep quality were associated with decreased likelihood of engaging in alcohol use. No other person- or day-level associations between sleep and alcohol use emerged.

CONCLUSIONS

Better sleep quality may be protective against alcohol use in AYA, and female AYA who report poorer sleep quality may experience higher levels of alcohol craving. Research and clinical assessment of AYA sleep quality can contribute to understanding of factors promoting alcohol craving and use.

Socioeconomic Background and Self-Reported Sleep Quality in Older Adults during the COVID-19 Pandemic: An Analysis of the English Longitudinal Study of Ageing (ELSA)

The COVID-19 pandemic negatively impacted sleep quality. However, research regarding older adults' sleep quality during the pandemic has been limited. This study examined the association between socioeconomic background (SEB) and older adults' sleep quality during the COVID-19 pandemic. Data on 7040 adults aged ≥50 were acquired from a COVID-19 sub-study of the English Longitudinal Study of Ageing (ELSA). SEB was operationalized using educational attainment, previous financial situation, and concern about the future financial situation. Sociodemographic, mental health, physical health, and health behavior variables were included as covariates. Chi-squared tests and binary logistic regression were used to examine associations between SEB and sleep quality. Lower educational attainment and greater financial hardship and concerns were associated with poor sleep quality. The relationship between educational attainment and sleep quality was explained by the financial variables, while the relationship between previous financial difficulties and sleep quality was explained by physical health and health behavior variables. Greater financial concerns about the future, poor mental health, and poor physical health were independent risk factors for poor sleep quality in older adults during the pandemic. Healthcare professionals and service providers should consider these issues when supporting older patients with sleep problems and in promoting health and wellness.

Too tired to drink? Daily associations of sleep duration and fatigue with own and others' alcohol consumption

OBJECTIVE

To better understand how sleep is associated with alcohol consumption among college students, the present study tested whether last night's sleep duration and current day fatigue were associated with being around others who were drinking that night and, if so, with alcohol consumption.

METHOD

College student drinkers (N = 540; mean age = 18.78 years; 52% female; 86% White) reported daily for 30 days yearly for up to 4 years on aspects of their sleep, their own alcohol use, and the perceived drinking of others in an intensive longitudinal burst design.

RESULTS

Participants were less likely to report that they were with others who were drinking on evenings following higher than average sleep duration or greater than average daytime fatigue. In addition, experiencing greater than average daytime fatigue was associated with a lower likelihood of consuming any alcohol and lower levels of alcohol consumption at the daily level. Thus, daytime fatigue may be protective against alcohol consumption through both selection and behavior moderation.

CONCLUSIONS

Results may be useful in the development of interventions to prevent heavy drinking among college students. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Using Alcohol and Cannabis as Sleep Aids: Associations with Descriptive Norms Among College Students

PURPOSE

Young adults may use alcohol and cannabis as sleep aids, a risky behavior that can worsen sleep health over time and lead to substance dependence. Perceived norms for such risky behaviors are often overestimated and related to one's own use. This cross-sectional study examined: (a) the extent to which college students overestimated the prevalence of alcohol and cannabis use as sleep aids (i.e., perceived descriptive norms), and (b) the extent to which perceived descriptive norms were associated with students' own use of alcohol and cannabis as sleep aids.

METHODS

2,642 undergraduate college students (Mage = 18.84 years) reported past 30-day use of alcohol and cannabis as sleep aids. Participants also estimated the percent of college students who use alcohol and cannabis as sleep aids (i.e., perceived descriptive norms).

RESULTS

One-sample t-tests revealed participants, on average, overestimated the norms for using alcohol and cannabis as sleep aids. Participants who endorsed past 30-day use of these substances as sleep aids overestimated these norms to an even greater extent. Count regression models showed perceived descriptive norms were associated with students' use of alcohol and of cannabis as sleeps aids, in respective models, even when controlling for sleep difficulties.

CONCLUSIONS

College students may overestimate the prevalence of using alcohol and cannabis as sleep aids, and students who believe these behaviors are more normative report more frequent use of these substances as sleep aids. Taken together, findings may highlight the potential for norm-correcting strategies as a prudent approach to reducing/preventing the use of alcohol and cannabis as sleep aids.

Posttraumatic stress symptoms and substance use among college students: Exploring interactions with sleep quality and assigned sex

Substance use is widely recognized as a negative outcome following traumatic events and is tied to symptoms of posttraumatic stress (PTS). Sleep quality may influence the PTS and substance use association, particularly among college students who are at risk for poor sleep. The purpose of the present study was to examine the moderating effect of sleep quality on the relationship between PTS and substance use in a cohort of college students, with an exploratory aim of examining potential differences by assigned sex. A screening survey was completed by 2,767 students enrolled in a larger RCT examining various brief college student alcohol reduction strategies. Results found a significant two-way interaction between PTS symptoms and subjective sleep quality on weekly number of drinks and peak drinking occasion, where the significant positive association between PTS symptoms to weekly drinks and peak drinking occasion was only found for those who reported poor sleep quality. A similar pattern emerged for the significant two-way interaction between PTS symptoms and subjective sleep quality on cannabis use frequency. A significant three-way interaction (i.e., PTS Symptoms × Poor Subjective Sleep Quality × Assigned Sex) indicated the two-way interaction between PTS symptoms and sleep quality for both weekly drinks and cannabis use frequency was stronger among male compared to female participants. Study findings suggest sleep quality is an important factor contributing to the relation between PTS symptom severity and substance use among college students. Strategies for assessing and improving sleep quality and PTS symptoms can be incorporated into prevention and intervention efforts targeting substance use related harm for college students.

Daily-level associations between sleep duration and next-day alcohol and cannabis craving and use in young adults

STUDY OBJECTIVES

To examine the effects of sleep duration on next-day alcohol and cannabis craving and use among young adults.

METHOD

A community sample of young adults who reported recent simultaneous alcohol and cannabis use at screening (N = 409; Mage = 21.61; 50.9% female) completed twice daily surveys (morning and afternoon) for five 14-day sampling bursts (i.e., 70 days total). Daily measurements included sleep duration, alcohol and cannabis craving, and alcohol and cannabis use (i.e., number of drinks, hours high). Multilevel models enabled examining associations between sleep duration and substance use/craving at three distinct levels: daily-level, burst-level, and person-level.

RESULTS

At the day-level, sleep duration was inversely associated with craving for both alcohol and cannabis: Stronger craving was reported on mornings and afternoons after relatively shorter sleep duration. At the burst-level, sleep duration was inversely associated with morning and afternoon alcohol craving indicating stronger alcohol craving, but not cannabis craving, during two-week periods when young adults have accumulated shorter sleep duration. Pertaining to alcohol and cannabis use, no daily-level effects were found, but the burst-level effect showed that participants engaged in greater alcohol use during two-week bursts with shorter sleep duration.

CONCLUSIONS

Based on a non-clinical sample of young adults reporting substance use, results suggest shorter sleep duration may be a modifiable risk factor as it pertains to substance use and cravings. Results highlight day-level effects of shorter sleep duration on substance use cravings and adverse effects of cumulative sleep deficit on alcohol use.

Alcohol Use Motives and Cannabis Use among Young Adults: Between- and Within-Person Associations Based on Monthly Data from a Community Sample

Objective: Alcohol use motives may characterize types of drinking that have unique associations with cannabis use and illuminate psychological processes underlying cannabis use. This study examined how alcohol use motives, both on average across two years and in a particular month, were associated with any and frequent cannabis use. Method: A young adult community sample (n = 486; 54% female, age 18-23 at enrollment) who used alcohol and cannabis in the year prior to study enrollment provided two years of monthly data. Multilevel logistic regression models predicting any and frequent (10+ occasions) past-month cannabis use estimated both between- and within-person effects of alcohol use motives, controlling for frequency of alcohol use and demographic covariates. Results: Alcohol use frequency was positively associated with any cannabis use at the between- and within-person levels and frequent cannabis use at the within-person level. Across two years, individuals who had higher average coping drinking motives and lower average social and conformity drinking motives were more likely to use cannabis frequently. Further, between-person variation in social motives was negatively associated with any cannabis use. Within-person, months with greater enhancement and social motives were associated with higher probability of any cannabis use. Conclusions: Using alcohol for coping reasons, rather than other-focused social reasons, indicated greater risk for frequent cannabis use, although drinking for social and enhancement reasons in a particular month signaled slightly increased short-term probability of any cannabis use. Assessment of alcohol motives may help guide targeting and timing of prevention related to cannabis use.

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.

Cannabis and Alcohol Use and Their Associations with Sleep: A Daily Diary Investigation of Single-Use and Co-Use in College Students

Introduction: Sleep continuity problems are widespread among college students and may be influenced by single-use and co-use of alcohol and cannabis. We examined the within-person associations of alcohol and cannabis use with subsequent sleep experiences in the everyday life of college students. Materials and Methods: A sample of 80 college students reported prior-night alcohol and cannabis use and sleep experiences for 14 consecutive days. Mixed-effects models examined the within-person relationships between alcohol and cannabis use (single- and co-use) and subsequent (1) sleep-onset latency, (2) total sleep time, (3) number of awakenings, and (4) early awakenings that night. Results: Compared to no-use evenings, alcohol and cannabis, used separately or together (co-use), were associated with shorter sleep-onset latency and longer total sleep time. Students reported more nightly awakenings after alcohol-only use compared to no-use and after co-use, and they reported fewer early awakenings after no-use and co-use. Conclusions: In line with previous experimental findings, we found that alcohol and cannabis use in the everyday life of college students were associated with sleep-inducing effects, and that alcohol use was associated with disturbed sleep continuity. The results suggest that cannabis may curb alcohol's detrimental effect on the number of awakenings and may reduce the incidence of early awakenings. Yet, due to lack of control for potentially important confounders (e.g., quantity of cannabis/alcohol consumed, withdrawal) the current results may be best seen as preliminary and further research is needed before causal inferences can be reached.