Observing client-therapist interaction in behaviour therapy: development and first application of an observational system.

A category system for coding the interaction in psychotherapy (CIP) is presented. Six therapists carried out 64 standardized intake sessions with clients presenting with chronic insomnia. The sessions were fully coded by three raters using the CIP. The 19 client categories as well as the 18 therapist categories showed sufficient reliability with kappa coefficients of 0.80 and 0.79 respectively. The frequencies of the client and the therapist categories of the first versus the second half of the interview were compared. Shifts in the behavioural patterns of therapists and clients during the course of the interviews are in accordance with the given rationale of the session. Correlations between the observational data and subjective ratings of the participants are further evidence for the utility of the CIP.