Objective: The study investigates the effectiveness of long-term psychotherapies. Cognitive-behaviour therapy was compared with psychoanalytic and psychodynamic therapy in the treatment of patients with a primary diagnosis of unipolar depression.
Method: In a prospective, quasi-experimental design 100 patients were compared at pre- and post-treatment and three-year follow-up. Outcome measures were the Beck Depression Inventory and Global Severity Index for measuring symptoms, the Inventory of Interpersonal Problems and the Social Support Questionnaire for measurement of social-interpersonal functioning, and the INTREX Introject Questionnaire for measuring personality structure. Comparative effectiveness of the experimental groups was analyzed using mixed models.
Results: We found significant outcome differences between psychoanalytic therapy and cognitive-behaviour therapy in depressive and global psychiatric symptoms, partly social-interpersonal and personality structure at three-year follow-up. Psychodynamic therapy was superior to cognitive-behaviour therapy in the reduction of interpersonal problems.
Conclusion: Psychoanalytic therapy shows significantly longer-lasting effects compared to cognitive-behaviour therapy three years after termination of treatment, which is discussed as a dose-effect.