Examining Transdiagnostic Outcomes from the Depression Prevention Initiative

Introduction: This randomized controlled trial compared an indicated depression prevention program, Interpersonal Psychotherapy-Adolescent Skills Training (IPT-AST; Young & Mufson, 2003), to group counseling (GC) delivered by school counselors. Significant differences in rates of change were found on the primary outcomes: depression symptoms and overall functioning. While these positive effects are encouraging, it is important to examine the effects of these programs on other outcomes. Internalizing and externalizing problems are particularly relevant given the high rates of comorbidity with depression in youth.

Method: Youth reported on internalizing and externalizing symptoms using the Youth Self-Report (YSR). Changes from baseline to the 6-month follow-up were examined using hierarchical modeling. A piecewise linear model which quantified change from baseline to post-intervention (active phase) followed by change from post-intervention to the 6-month follow-up (follow-up phase) fit the data best. In addition, we also derived overall change scores which quantified change from baseline to the 6-month follow-up.

Results: First, we examined changes on broadband internalizing and externalizing symptoms. On the internalizing scale, there were significant differences in rates of change during the active phase (p < .01, d = .54) and overall from baseline to the 6-month follow-up (p = 0.03, d = .33), favoring IPT-AST. On the externalizing scale, IPT-AST youth showed significantly greater decreases during the active phase (p = .01, d = .37) than GC. However, there were no significant differences in rates of follow-up change or overall change between the two conditions. Second, to understand which domains were driving these differences, we examined changes on the subscales that derive these broadband scales (internalizing: anxious/depressed, withdrawn/depressed, somatic complaints; externalizing: aggressive behavior, rule-breaking behavior). Youth in IPT-AST showed significantly greater improvements in anxious/depressed symptoms and withdrawn/depressed symptoms than GC youth during the active phase and overall. A different pattern of findings emerged for somatic complaints: IPT-AST youth had significantly greater decreases during the active phase, while GC youth had significantly greater decreases during the follow-up phase. As a result, there was not a significant difference in overall rates of change on somatic symptoms. Within the externalizing domain, there were significant between-group differences on the aggressive behaviors subscale during the active phase, favoring IPT-AST. Rates of change were not significantly different between the two groups during the follow-up phase or overall. There were no significant differences in rates of change in rule-breaking behavior.

Conclusion: The results add additional support to previous research supporting the efficacy of IPT-AST and suggest that the effects of IPT-AST extend beyond depressive symptoms to internalizing and externalizing problems more broadly. Specifically, IPT-AST has effects on anxiety and aggression, at least in the short-term. Future research will examine the long-term impact of these programs to see if effects persist over time.