Therapist-rated outcomes in a randomized clinical trial comparing cognitive behavioral therapy and psychodynamic therapy for major depression

Background: The efficacy of psychodynamic therapy (PDT) for depression is debated due to a paucity of high-quality studies. We compared short psychodynamic supportive psychotherapy (SPSP) to cognitive behavioral therapy (CBT) in a randomized clinical trial. We used therapist-rated outcomes to examine how the course of change during treatment could be best represented and to compare treatment efficacy, hypothesizing non-significant differences.

Methods: Three hundred and forty-one adults meeting DSM-IV criteria for a depressive episode and with Hamilton Depression Rating Scale (HAM-D) scores ≥14 were randomized to 16 sessions of individual manualized CBT or SPSP. Severely depressed patients (HAM-D>24) received additional antidepressant medication. After each session, therapists rated the Clinical Global Impression Scale subscales 'Severity of Illness' (CGI-S) and 'Global Improvement' (CGI-I), and the DSM-IV Axis V Global Assessment of Functioning Scale (GAF). We fitted growth curves using mixed model analyses with intention-to-treat samples.

Results: CGI-S and GAF scores during treatment were best represented by a linear symptom decrease. CGI-I scores were best represented by an S-shaped curve with relative more improvement in the first and last phases than in the middle phase of treatment. No significant post-treatment treatment differences were found. A non-significant trend for a treatment effect on CGI-S scores vanished when controlling for therapist gender and profession.

Limitations: Therapists were not specifically trained for CGI and GAF assessments.

Conclusions: These findings add to the evidence-base of PDT for depression. Therapist characteristics and differences between severity and improvement measures might influence ratings and need to be taken into account when using therapist-rated outcome measures.