Dynamic patterns in psychotherapy--discontinuous changes and critical instabilities during the treatment of obsessive compulsive disorder.

In therapy processes of a variety of disorders, discontinuous trajectories of symptom changes have been identified. In this study, we are reporting on such 'sudden gains' that occur in the treatment of clients with obsessive-compulsive disorder (OCD) following cognitive-behavioral group therapy. Time series analysis of data taken from 18 OCD clients revealed that a discontinuously shaped symptom reduction took place already before exposure/response prevention (ERP) in a large number of clients. Coincidently with the steepest gradient of symptom change an increased level of dynamic complexity in daily ratings of 47 items of a specific change questionnaire was observed. Our results support hypotheses from the theory of complex self-organizing systems, postulating nonstationarity and critical instabilities during order transitions. Our study underlines the usefulness of real-time monitoring procedures with high-frequency ratings (daily measurements) in therapeutic routine practice.