Cognitive versus behavioral skills in CBT for depressed adolescents: Disaggregating within-patient versus between-patient effects on symptom change.

Objective: Despite a growing body of research supporting the efficacy of cognitive-behavioral therapy (CBT) for depressed adolescents, few studies have investigated the role of the acquisition and use of CBT skills in accounting for symptom improvement. The present study examined the role of cognitive versus behavioral skills in predicting symptom improvement in depressed youth. Analyses considered different raters of patient skills (patient vs. therapist) as well as disaggregated between-patient versus within-patient effects. Method: Data were derived from a 12-week clinical trial of CBT for depressed adolescent females (N = 33; ages 13—18 years; 69.7% White). Both therapist-report and patient-report measures of CBT skills (skills of cognitive therapy) were acquired at 5 time points throughout therapy: Sessions 1, 3, 6, 9, and 12. Depressive symptoms (Beck Depression Inventory-II) were assessed at every session. Results: Therapist and patient ratings of CBT skills showed small to moderate associations (rs = .20—.38). Intraclass correlation coefficients indicated that the majority of the variance in skills scores (61—90%) was attributable to within-patient variance from session to session, rather than due to between-patient differences. When disaggregating within-patient and between-patient effects, and consistent with a causal relationship, within-patient variability in both patient-rated (b = −2.55; p = .025) and therapist-rated (b = −2.41; p = .033) behavioral skills predicted subsequent symptom change. Conclusions: Analyses highlight the importance of the acquisition and use of behavioral skills in CBT for depressed adolescents. Findings also underscore the importance of disentangling within-patient from between-patient effects in future studies, an approach infrequently used in process-outcome research. (PsycINFO Database Record (c) 2019 APA, all rights reserved)