Trajectories and mediators in psychotherapy were investigated in a process-outcome study.
One hundred patients with depression were randomly assigned to psychoanalytic therapy (PA), psychodynamic therapy (PD), or cognitive behavioral therapy (CBT). Measurements were taken before the start of treatment, every six months during ongoing treatment, and at the 3-year follow-up. Outcome trajectories were assessed using the Beck Depression Inventory (BDI; Hautzinger et al. 1994), the Symptom Checklist (SCL-90-R; Franke 1995), and the Inventory of Interpersonal Problems (IIP; Horowitz, Strauss, and Kordy 2000). The following mediators were tested: the working relationship, measured using the Helping Alliance Questionnaire (HAQ; Bassler, Potratz, and Krauthauser 1995), and introjects, measured using the INTREX, Introject Positive (Tress 1993). Multilevel models were used to estimate the trajectories and test for mediation.
Results: Symptoms decreased shortly after the start of treatment and continued to decline in all treatment groups. After the end of treatment, the trajectories of symptoms continued to decline in PA to a significant extent compared to PD and CBT. In the early treatment phase, interpersonal problems decreased significantly in PD compared to PA and CBT, but in the further course of treatment, the improvements in interpersonal problems were greatest in PA and increased significantly again after the end of treatment compared to CBT. Mediator analysis showed that the introject was positive and the working alliance was not a mediator for the differential therapy effect.
Original language: German