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

Abstract

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 mari...

Using substances to cope with social anxiety: Associations with use and consequences in daily life.

“…Young adults are a high-risk group for alcohol and cannabis use; among a national United States sample of young adults, the majority reported alcohol use, and nearly half reported cannabis use in the past 12 months (Patrick et al, 2022). Further, many young adults engage in simultaneous use (using both alcohol and cannabis at the same time, so that effects overlap) and same-day co-use (using alcohol and cannabis on the same day, but not necessarily at the same time; Lee et al, 2022). Research has identified substance use motives as one of the most proximal predictors of substance use behaviors.…”

Daily Order of Alcohol and Cannabis Use Predicts Drinking Quantity on Simultaneous Use Days, but Substance Use Motives do not Moderate

“…Past daily studies comparing alcohol use and intoxication levels across alcoholonly and co-use days show mixed findings (Lee et al, 2022). To my knowledge, the present study is the first to show that students may drink more heavily when using alcohol first on SAM use days, helping to explain past discrepancies in alcohol use across days.…”

Effects of combined use of alcohol and delta-9-tetrahydrocannibinol on working memory in Long Evans rats

“…Interest in understanding the risks conferred by patterns of simultaneous use has been increasing (Lee et al, 2022) alongside the greater incidence of co-use in young adults (McCabe et al, 2021). Most of the research in the human literature focuses on acute effects of simultaneous use, and specifically on the immediate consequences that are self-reported by users of these drugs (Lee et al, 2022).…”

“…Interest in understanding the risks conferred by patterns of simultaneous use has been increasing (Lee et al, 2022) alongside the greater incidence of co-use in young adults (McCabe et al, 2021). Most of the research in the human literature focuses on acute effects of simultaneous use, and specifically on the immediate consequences that are self-reported by users of these drugs (Lee et al, 2022). When longitudinal studies are conducted, they most frequently compare “heavy” users of one or both drugs to non-using controls, and even then the criteria for heavy frequency of use is inconsistent, making it difficult to paint a comprehensive picture (Karoly et al, 2020).…”