An examination of the protective role of internalizing symptoms in adolescent substance use

Although psychological symptoms are broadly considered to be risk factors for substance use, internalizing symptoms may be associated with lower risk for adolescent substance use after controlling for co-occurring externalizing symptoms. The present study explored two potential mediators of this protective association between internalizing symptoms and adolescent substance use: popularity and harm avoidance. The study used data from the Colorado Longitudinal Twin Study (LTS) and Colorado Adoption Project (CAP). Annual assessments of internalizing and externalizing symptoms and social competence were completed by parents and teachers at participant ages 7 to 16. Harm avoidance and substance use were assessed at age 17. In this sample, internalizing symptoms were associated with less frequent substance use, controlling for externalizing symptoms. We did not find evidence that popularity or harm avoidance accounts for the protective association of internalizing symptoms with adolescent substance use. Teacher-reported popularity was associated with less frequent substance use, suggesting that social connectedness in the school context may be a protective factor for adolescent substance use. Harm avoidance was not associated with substance use after accounting for internalizing and externalizing symptoms.