Methodological aspects of controlled psychotherapy trials

The present paper deals with selected aspects of psychotherapy research. Psychotherapy is an effective treatment approach for mental disorders. Since research in psychotherapy is entirely dependent on public funding, several research questions remain open. Psychotherapy efficacy studies can be conducted in a randomised, but not in a placebocontrolled or double-blind manner. Apart from the effect of psychotherapy on the main outcome variables, one has to differentiate between specific and common factors of psychotherapy. Research in psychotherapy will gain societal relevance only after effective approaches have been successfully implemented in general practice. Transfer studies thus represent a new challenge in psychotherapy research. The funding activity of the German Federal Ministry of Education and Research (BMBF) "Networks in Research on Psychotherapy'' made it possible that for the first time large multicentre psychotherapy studies meeting GCP criteria can be conducted in Germany. These studies will generate highly innovative and in part unique findings.