AIM: (Partial) inpatient psychotherapy is well implemented in Germany. To better understand efficacy factors and effects, efficacy studies are necessary. This naturalistic study investigates the effectiveness of inpatient and day clinic psychotherapy as well as patient-and disorder-related factors influencing individual symptom improvements.

METHODS: Patients at a psychosomatic-psychotherapeutic university hospital treated from 2015 to 2019 who completed the BSI-18 either at admission and discharge (n=1366) or at admission and three-month catamnesis (n=497) were included in the analysis.

RESULTS: Improvements in global symptom severity showed moderate effect sizes. Descriptively, these were larger for day clinic patients than for those receiving treatment as inpatients-especially in the follow-up comparison (immediately after discharge: dinpatient=0.401, dday clinic=0.482; three months after discharge: dinpatient=0.403, dday clinical=0.807). Day hospitalized patients differed significantly from inpatients-slightly in age, employment status, ability to work and initial symptom burden, moderately in the number of mental comorbidities and strongly in their main diagnoses. Socio-demographic factors showed no positive influence on symptom improvement, initial symptom severity a moderate positive influence and the number of mental comorbidities a complex influence.

DISCUSSION: In general, this study confirms the effectiveness of (partial) inpatient psychosomatic therapy. The relevance of day clinic offers is emphasised in the context of cost efficiency and good integration into everyday life, but under consideration of individual treatment indications.