Reduced substance use as a secondary benefit of an indicated cognitive–behavioral adolescent depression prevention program.

Our first aim was to test whether a group cognitive-behavioral (CB) depression prevention program reduces substance use escalation over 2-year follow-up relative to two active comparison interventions and a brochure assessment control. Our second aim examined whether reductions in depressive symptoms mediate intervention effects, as posited by the affect-regulation model of substance use. In this indicated prevention trial, 341 high school adolescents at risk for depression because of the presence of elevated depressive symptoms were randomized to a Group CB intervention, group supportive-expressive group intervention, CB bibliotherapy, or educational brochure control condition. Participants in Group CB had significantly lower rates of substance use compared with brochure control participants at both 1- and 2-year follow-up and lower substance use at 2-year follow-up relative to bibliotherapy participants; no other condition differences were significant. Mediational analyses suggested that reductions in depressive symptoms from baseline to posttest accounted for changes in substance use over 2 years for participants in Group CB relative to brochure control participants but did not mediate effects relative to those receiving bibliotherapy. Results suggest that a secondary benefit of this CB group indicated depression prevention program is lower rates of long-term substance use. Findings supported the hypothesis that, relative to a nonactive comparison condition, reductions in depressive symptoms mediated the effects of Group CB prevention on substance use escalation.