Therapist differences in cognitive-behavioral psychotherapy for generalized anxiety disorder: a pilot study

Little is known about factors differentiating more and less effective therapists or the mechanisms through which therapists influence outcome. In the present study, the performance of a small sample of 4 therapists was compared in the context of delivering cognitive-behavioral psychotherapy (CBT) to 32 clients with generalized anxiety disorder. More effective therapists were characterized by higher observer-rated CBT competence, higher client outcome expectations and client treatment credibility assessments, and higher early treatment client ratings of therapeutic alliance quality. Higher early CBT competence was associated with higher client midtreatment outcome expectations, which in turn were associated with better posttreatment outcomes. Although these findings are preliminary given the small sample of therapists and clients, they suggest that the common factor of outcome expectations might be a mechanism through which the specific factor of psychotherapist competence exerts its influence on treatment outcome. The implications of these findings and directions for future research are discussed.