Concurrent Polysubstance Use in College Students: A Brief Social Norms Intervention to Abate Use

Abstract

Introduction: Many college students engage in marijuana and alcohol use, as well as concurrent and simultaneous polysubstance use of both of these substances (CPU, SPU). The literature on CPU and SPU in this population has not been comprehensively reviewed. It is also unclear whether when compared with concurrent users, simultaneous users experience increased risk of substance-related problems (problems), and if a brief normative feedback (NF) intervention is feasible for and can impact marijuana and alcohol use by concurrent users. Methods: This study involved: Paper 1) a narrative review of literature on marijuana and alcohol use and CPU and SPU in college students, Paper 2) secondary analysis to compare odds of experiencing problems between concurrent and simultaneous users, and Paper 3) the development and provision of a Web-based NF intervention targeted at freshmen. Intervention conditions included marijuana-only NF, alcohol-only NF and both marijuana and alcohol NF, with a one-month follow-up assessment. Results: Paper 1 found that CPU may increase students’ risk of experiencing problems and that more studies are needed to better understand CPU and SPU in college students. One-way ANOVA models in Paper 2 found that compared to concurrent users, simultaneous users engaged in more substance use. The odds of respondents in the two groups reporting some of the individual problems and experiencing four or more problems in the previous month were significantly different in multiple logistic regression models. Paper 3 found that provision of marijuana and alcohol NF to concurrent users is feasible. Significant time effects were found for five of the nine outcome variables related to norms perceptions, substance use and problems during linear mixed-models for repeated analyses. No significant condition or condition*time effects were found. Conclusions: More research is needed to further understand CPU and SPU and the potential for experiencing increased substance use and problems. This knowledge could be used to tailor prevention interventions to these patterns of use. It appears possible to deliver marijuana NF, both alone and alongside alcohol NF, but more research is needed to determine if marijuana use can effectively be modified with brief interventions that have been supported for alcohol prevention.