Randomized Trial of Interpersonal Psychotherapy and Cognitive Behavioral Therapy for Major Depressive Disorder in a Community-Based Psychiatric Outpatient Clinic

Abstract

Background: Interpersonal psychotherapy (IPT) and cognitive behavioral therapy (CBT) are both evidence-based treatments for major depressive disorder (MDD). Several head-to-head comparisons have been made, mostly in the United States. In this trial, we compared the two treatments in a small-town outpatient psychiatric clinic in Sweden. The patients had failed previous primary care treatment and had extensive Axis-II comorbidity. Outcome measures were reduction of depressive symptoms and attrition rate. Methods: Ninety-six psychiatric patients with MDD (DSM-IV) were randomized to 14 sessions of CBT (n = 48) or IPT (n = 48). A noninferiority design was used with the hypothesis that IPT would be noninferior to CBT. A three-point difference on the Beck Depression Inventory-II (BDI-II) was used as noninferiority margin. Results: IPT passed the noninferiority test. In the ITT group, 53.5% (23/43) of the IPT patients and 51.0% (24/47) of the CBT patients were reliably improved, and 20.9% (9/43) and 19.1% (9/47), respectively, were recovered (last BDI score <10). The dropout rate was significantly higher in CBT (40%; 19/47) compared to IPT (19%; 8/43). Statistically controlling for antidepressant medication use did not change the results. Conclusions: IPT was noninferior to CBT in a sample of depressed psychiatric patients in a community-based outpatient clinic. CBT had significantly more dropouts than IPT, indicating that CBT may be experienced as too demanding. Since about half the patients did not recover, there is a need for further treatment development for these patients. The study should be considered an effectiveness trial, with strong external validity but some limitations in internal validity.