Lifetime use of multiple substances and youth suicide risk: assessing the role of depressive symptoms using structural equation modeling

This study assessed the direct and indirect effects (via depressive symptoms) of lifetime use of a broad range of substances on suicide risk among US adolescents. This was a cross-sectional study. Data from the 2021 Youth Risk Behavior Survey were used (N = 12,303, 48.7% female). Associations between five types of substance use (cigarette, e-cigarette, alcohol, marijuana, and prescription pain medicine) and three dimensions of suicide risk (suicidal ideation, suicide plan, and suicide attempt) were measured by multivariate logistic regression models. The role of depressive symptoms was further examined by structural equation modeling. Almost three in five (57.5%) adolescents had used one or more substances in their lifetime (18.1% one type, 12.2% two types, 13.1% three types, 10.2% four types, and 3.8% five types). Adolescents using five substances were up to 16 times more likely to experience suicidal ideation and behaviors. Depressive symptoms significantly linked the pathway from substance use to suicide risk, resulting in much stronger indirect effects than the direct effects. Collectively, the five substance use behaviors and depressive symptoms explained about 60.4% of variance in suicidal ideation, 53.6% of variance in suicide plan, and 55.0% of variance in suicide attempt. Lifetime use of multiple substances is significantly correlated with suicidal ideation and behaviors among adolescents via the pathway of depressive symptoms. Routine screening for a broad range of substance use behaviors is needed to identify adolescents at risk for suicide and accessible mental health services could potentially attenuate the linkage between substance use and suicide risk.