Abstract
IntroductionMany young adults report frequent co-use of alcohol and marijuana, with some individuals engaging in simultaneous use (SAM; use of both substances within the same occasion resulting in an overlap of their effects) and others in concurrent use (CAM; use of both substances during a similar time period [e.g., past 30 days] but not within the same occasion). Emerging work demonstrates that SAM relative to CAM use places individuals at a greater risk for substance-related harms; however, these results primarily rely on U.S. samples. The goal of the present multi-country study was to examine prevalence rates of CAM and SAM use and examine differences in past 30-day SAM/CAM use on alcohol/marijuana substance-related outcomes among college students from seven countries. MethodsA total of 9171 (70.5% women; Mean age = 20.28, SD = 3.96) college students participated in the cross-sectional online survey study. ResultsAmong students who endorsed use of both alcohol and marijuana in the past 30-days (n = 2124), SAM use (75.8%) was far more prevalent than CAM use (24.2%). Moreover, ∼75% of students endorsed SAM use within each country subsample. Regression models showed that SAM vs. CAM use was associated with greater alcohol and marijuana use and negative consequences. ConclusionsCollege students from around the world endorse high rates of SAM use, and this pattern of co-use is associated with greater frequency of use and substance-related harms. On college campuses, SAM use should be a target of clinical prevention/intervention efforts and the mechanisms underpinning the unique harms of SAM need to be clarified.
Highlights
Many young adults report frequent co-use of alcohol and marijuana, with some individuals engaging in simultaneous use (SAM; use of both substances within the same occasion resulting in an overlap of their ef fects) and others in concurrent use (CAM; use of both substances during a similar time period [e.g., past 30 days] but not within the same occasion)
Among students who reported both alcohol and marijuana use dur ing the last 30 days, the results showed similar prevalence rates of Simultaneous alcohol and marijuana (SAM) vs concurrent alcohol and marijuana (CAM) (~75% vs 25%, respectively) that have been found in a previous sample of U.S students (76.9% SAM vs 23.1% CAM use; Looby et al, 2021)
Our results suggest that the alcohol—marijuana consumption patterns and consequences associated with SAM found in previous studies within U.S can be expected in young adult college students from other countries
Summary
Many young adults report frequent co-use of alcohol and marijuana, with some individuals engaging in simultaneous use (SAM; use of both substances within the same occasion resulting in an overlap of their ef fects) and others in concurrent use (CAM; use of both substances during a similar time period [e.g., past 30 days] but not within the same occasion). Results: Among students who endorsed use of both alcohol and marijuana in the past 30-days (n = 2124), SAM use (75.8%) was far more prevalent than CAM use (24.2%). Conclusions: College students from around the world endorse high rates of SAM use, and this pattern of co-use is associated with greater frequency of use and substance-related harms. Alcohol and marijuana use among college students is a significant public health concern because rates of use and the number of substance use-related negative consequences are high (Bravo, Pearson et al, 2019; Bravo et al, 2019; Krieger et al, 2018). Individuals that engage in SAM use are significantly more likely to experience negative consequences (Cummings et al, 2019; LindenCarmichael et al, 2020; Jackson et al, 2020), including driving under the influence (Terry-McElrath et al, 2014; Subbaraman & Kerr, 2015)
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