More drugs, more problems? Simultaneous use of alcohol and marijuana at parties among youth and young adults

Background: Simultaneous alcohol and marijuana (SAM) use by youth and young adults often occurs at parties and may result in an increased risk of experiencing adverse consequences compared to use of either substance alone. This study sought to examine the relationship between SAM use by youth and young adults and consequences experienced at, or immediately following, parties. Methods: We conducted a repeated cross-sectional survey of 15 to 20-year-olds residing in 24 communities across seven states within the United States in 2015 and 2016 (n = 2681). Logistic regression analyses were used to examine associations between SAM use and six consequences (e.g. hangover, sex without a condom, involved in a fight) among 834 youth and young adults (53.7% female, 78.3% White, mean age: 18.4 years) who reported using either alcohol or marijuana at the last party they attended. Results: 72.3% consumed alcohol exclusively, 5.2% used marijuana exclusively, and 22.5% engaged in SAM use. In multivariable analyses, those who reported SAM use had significantly greater odds of experiencing any (AOR = 1.9; 95% CI: 1.3, 2.8) and 2 or more (AOR = 4.0; 95% CI: 2.0, 8.0) consequences compared to those who used only alcohol. Conclusions: Our findings suggest that SAM use in a party context is associated with an increased risk of experiencing consequences among youth and young adults after controlling for the quantity of alcohol consumed. Policy and educational prevention strategies should target SAM at parties to reduce harms among youth and young adults.