[Response and remission in psychotherapy research].

Treatment effects of psychotherapy are usually studied using analysis of mean differences, tests of significance and effect size measures. These strategies, however, do not answer the question of how large the proportion of patients is who responded to treatment or who even reached remission. This article compares 2 competing methods of response and remission analysis: The Reliable Change Index (RCI) according to Jacobson et al. and the method of percent symptom reduction (PSR). We applied both methods using a sample of 338 patients with DSM-IV major depressive disorder. A pre-post treatment effect of Cohen's d=1,16 (intention-to-treat) resulted for the Beck Depression Inventory (BDI), corresponding to response rates of 54-65% and remission rates of 42-48%. We demonstrate that the PSR method had some important advantages over the RCI. It is recommended to classify patients as responders in depression psychotherapy if they improve at least 50%. © Georg Thieme Verlag KG Stuttgart · New York.