Prevalence and correlates of youth poly-substance use in the COMPASS study

Background and Aims Youth poly-substance use, associated with long-term negative health and social outcomes, is of increasing concern following the rise of e-cigarette vaping and cannabis legalization in Canada. This work aimed to investigate current evidence on correlates of this behaviour to inform effective prevention and harm reduction programming. Design Cross-sectional sample taking part in a cohort study. Setting Canadian high schools (AB, BC, ON, QC) Participants 74,501 Canadian high school students who completed the COMPASS student questionnaire in 2018/2019. Measurements Self-report data on use of five substances (alcohol, cigarettes, e-cigarettes, cannabis, and opioids) alongside demographic factors, social and school support, and mental health-related measures. Results Of the 39% of youth who reported current substance use, 53% reported using two or more. E-cigarette vaping was most prevalent (28%) and most often combined with other substances. Feeling supported by friends and having no problem with seeking help at school were associated with higher levels of poly-substance use. Family support, school connectedness, and school support to resist drugs decreased the risk of substance co-use. Conclusions The evidence presented here suggests that interventions for youth poly-substance use should rely on joint efforts between parents, schools, and communities to focus on structural factors rather than problematizing the individual.