Cognitive Behavioral Analysis System of Psychotherapy for inpatients with persistent depressive disorder: a naturalistic trial on a general acute psychiatric unit.

The Cognitive Behavioral Analysis System of Psychotherapy (CBASP) was originally developed for outpatients with persistent depressive disorder (PDD). We adapted CBASP as inpatient treatment on a general acute psychiatric ward and evaluated its outcome and feasibility. Sixty PDD patients received a 12-week multidisciplinary CBASP program. Hamilton Depression Rating Scale (HAMD24) and Beck Depression Inventory (BDI-II) served as primary and secondary outcome measures. Childhood maltreatment at baseline and change in interpersonal distress from pre to post were investigated as predictors of treatment outcome. A 6-month follow-up assessment was conducted. Feasibility was assessed through dropouts and satisfaction with the program. Fifty patients completed the program (16.7% dropouts). An ANOVA with three repeated measurements (pre, post, FU) in the ITT sample revealed a main effect of time. For the primary outcome, depressive symptoms decreased from pre (28.3) to post (11.5, response rate: 72.7%, d = 1.8), and from pre to FU (13.9, d = 1.2). Four patients relapsed. The secondary outcome confirmed the results; however, the response rate was lower (BDI-II: 31.7%, pre to post: d = 0.8, pre to FU: d = 0.3), and ten patients relapsed at FU. Reduction in interpersonal distress, but not childhood maltreatment, predicted BDI-II response. Key limitations of this naturalistic open trial are the lack of a comparison group and non-blinded HAMD24 ratings. Inpatient CBASP for PDD appears feasible on a general acute psychiatric ward with effect sizes comparable to specialized psychotherapy wards and to the outpatient setting.