Therapist effects on outcome and alliance in inpatient psychotherapy

As an addition to the ongoing discussion concerning the magnitude of therapist effects on outcome in psychotherapy, we investigated therapist variability in a large inpatient psychotherapy sample. We included global symptomatic outcome (Global Severity Index of the Symptom Checklist-90 Revised [SCL-90-R]; German version, Franke, 1995) and alliance (Helping Alliance Questionnaire; German version, Bassler, Potratz & Krauthauser, 1995) ratings of 2554 inpatients who were treated by 50 psychotherapists. Multilevel regression analyses (HLM; Raudenbush, Bryk, Cheong, & Congdon, 2004) were used for analyses. Overall, therapists accounted for a much greater variability on alliance (33%) than on outcome (3%). Therapists were differentially effective with regard to their patients' symptom severity at the beginning of treatment, and therapists differed in the degree that a positive alliance was associated with therapeutic outcome. The relatively small therapist effect on outcome is attributed to compensatory mechanisms in the specific context of inpatient therapy. Keywords: therapist effects; inpatient psychotherapy; outcome; alliance; multilevel analyses