Session-to-session Effects of Therapist Adherence and Facilitative Conditions on Symptom Change in CBT and IPT for Depression.

Objective: The objective of this study was to analyze the effect of adherence to both specific technique factors and facilitative condition variables (e.g., therapists' involvement, understanding and support) in Cognitive Behavior Therapy (CBT) and Interpersonal Psychotherapy (IPT). In addition, we were interested in whether the effect of therapist adherence would depend on the level of the working alliance. Method: Three sessions each from 74 patients diagnosed with Major Depressive Disorder who were randomized to 14 sessions of IPT or CBT were rated for adherence using a modified version of The Collaborative Study Psychotherapy Rating Scale-6 (CSPRS-6). Data was analyzed using Multilevel Modeling. Results: No effects of adherence to specific factors on outcome were found in neither CBT nor IPT. Facilitative conditions were associated with better outcome in CBT but not in IPT, even after adjustment for the quality of the working alliance. No interaction effects were found. Conclusions: Our findings highlight the importance of relational factors in CBT, but do not support the need for specific adherence to any of the two treatments. Possible explanations of the findings and directions for future research are discussed.