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

Abstract

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.

Preliminary impact of the COVID-19 pandemic on smoking and vaping in college students

“…We recontacted 473 participants who completed the last wave of a longitudinal study on alcohol and cannabis co-use in college students ( Jackson et al, 2020 ). Criteria for being re-contacted comprised: 1) agreeing to be contacted for future studies and providing contact information, and 2) being a first- or second-year student during the baseline assessment of the parent study.…”

Co-Use of Alcohol and Cannabis: Longitudinal Associations with Mental Health Outcomes in Young Adulthood

“…Research on the consequences of SAM use at the between-person and within-person level suggest that SAM is associated with higher and more frequent levels of alcohol and marijuana use and with numerous alcohol-related consequences, including unsafe driving behaviors [ 9 , 10 , 11 ], social problems, substance use disorders, and cognitive problems compared to non-users or to youth who exclusively use either alcohol or marijuana, even after controlling for sociodemographic factors [ 5 , 12 , 13 , 14 , 15 , 16 , 17 ]. However, results from recent within-person studies suggest the observed associations between SAM use and negative consequences may largely be due to increases in alcohol consumed on SAM days, rather than SAM itself [ 16 , 17 , 18 ].…”

“…Others studies have found that SAM use (versus CAM use) is associated with heavier alcohol and cannabis use [ 1 , 5 ] and some (but not all) negative alcohol-related consequences. For example, in a recent study of US college students aged 18–24, SAM use was associated with an overall greater number of negative alcohol consequences than CAM, however risk for each individual specific consequence did not differ between SAM and CAM users after use and covariates were accounted for, except for blackouts [ 14 ]. Moreover, Subbaraman & Kerr [ 6 ] found that SAM use was associated with more risky driving behaviors compared to CAM use, but not more social harms.…”

“…Similarly, Linden-Carmichael et al, [ 15 ] found that more frequent SAM use among young adults was associated with heavier substance use and negative consequences relative to less frequent SAM use. However, Jackson et al [ 14 ], found no differences in outcomes based on frequency of SAM use. It remains uncertain if SAM use is associated with additional risk for these outcomes beyond CAM and whether there is a dose–response relationship between SAM use frequency and negative consequences.…”

Does the Combination Matter? Examining the Influence of Alcohol and Cannabis Product Combinations on Simultaneous Use and Consequences in Daily Life

“…Compared to co‐users who do not use both substances together or mono‐substance users, SAM users have reported higher levels of consumption (Brière et al, 2011; Gunn et al, 2018; Linden‐Carmichael et al, 2019; Metrik et al, 2018; Subbaraman and Kerr, 2015) and more negative consequences (Brière et al, 2011; Jackson et al, 2020; Midanik et al, 2007; Subbaraman and Kerr, 2015; Yurasek et al, 2017). In particular, SAM users were shown to be more likely to endorse 9 types of consequences, relative to alcohol‐only users, with the strongest effects observed for more acute consequences (e.g., blackouts; Jackson et al, 2020). Likewise, SAM users engage in riskier driving and perceive driving under the influence to be safer than co‐users and mono‐substance users (Duckworth and Lee, 2019).…”