Examining the Efficacy of Interpersonal Psychotherapy-Adolescent Skills Training (IPT-AST) through Systematic Pragmatic Case Studies

Background: Lifetime rates of depression nearly double between the ages of 13 and 18 (Wagstaff & Polo, 2012) and almost half of adolescents report at least subclinical depressive symptoms (Hankin, 2002).  Meta-analyses found that the average effect size for treating youth depression is medium (0.34) and the average effect size for preventing youth depression is small (0.15) (Stice, Shaw, Bohon, Marti, & Rohde, 2009).  These varied findings warrant a more nuanced analysis of the characteristics of the intervention, child, and setting that affect outcomes.  IPT-AST (Young & Mufson, 2003) is a school-based indicated prevention program that has been shown to have significant effects on depression symptoms and overall functioning for adolescents (Young, Mufson, & Gallop, 2010).  This paper will conduct a systematic pragmatic case study of a responder and non-responder to IPT-AST in Young et al. (2010) to better understand factors that impact intervention efficacy.

Methods/Results: The response and non-response cases were identified through careful examination of assessment data of the 36 participants randomized to the IPT-AST condition in Young et al. (2010) (N=57).  This data was collected at five time points over the course of the study: eligibility, baseline, post-intervention, six-months, 12-months, and 18-months post-intervention.  Students were considered non-responders if they experienced a consistent increase in depressive symptoms and met criteria for a depressive diagnosis during the intervention or follow-up period.  Responders were defined as students whose symptoms consistently improved and who did not meet criteria for a depressive diagnosis.  Qualitative data from audio recordings of clinical evaluations and the intervention were used in conjunction with quantitative data from self-report measures to examine experiences of the selected individuals throughout the study.  This paper will discuss how individual factors (e.g., attitudes towards change, negative cognitive style, anxiety symptoms, and interpersonal history), intervention factors (e.g., intervention goals and skills comprehension and practice), and group factors (e.g., trust) contributed to individual outcomes and implications for future research and program development.  

Conclusions: Using a mixed methods approach to examine varying outcomes of adolescents who participated in IPT-AST permits a more comprehensive understanding of the role of individual and environmental characteristics in adolescent response to depression prevention interventions in school settings.