How therapists' interpersonal behaviour is perceived by their patients and close others: A longitudinal and cross‐situational study

Due to their predictive abilities, therapist interpersonal behaviour is of great relevance for psychotherapy. However, there is a lack of knowledge about its stability inside but also outside of the therapy room within and between therapists. The current study investigates interpersonal behaviour of trainee therapists (N = 20) as perceived by four patients each suffering from generalized anxiety disorder and three closely related persons of every therapist (close others). Investigating repeated measures, four patients per therapist completed the Impact Message Inventory (IMI; Kiesler, 1987) three times over the course of their cognitive behavioural therapy. Furthermore, the IMI was completed by three close others at one assessment time. Therapist interpersonal behaviour was perceived as more friendly and less submissive when evaluated by close others compared to patients. Using a multilevel approach, our results indicate that therapists' interpersonal behaviour was perceived considerably stable across patients and over the course of treatment, and there is considerable uniformity of the IMI evaluations in respect to the particular subscales within and between therapists. Our results highlight the potential similarities of observer‐based habitual therapists' interpersonal behaviour inside and outside of the therapy room.