Interpersonal psychotherapy as add-on for treatment-resistant depression: A pragmatic randomized controlled trial

Abstract

Background: Treatment-resistant depression (TRD) is an extremely prevalent clinical condition. Although Interpersonal Psychotherapy (IPT) is an established treatment for uncomplicated depression, its effectiveness has never before been studied in patients with TRD in real-world settings. We investigate IPT as an adjunct strategy to treatment as usual (TAU) for TRD patients in a pragmatic, randomized, controlled trial.

Methods: A total of 40 adult patients with TRD (satisfying the criteria for major depressive disorder despite adequate antidepressant treatment) were recruited from a tertiary care facility for this pragmatic trial and blinded to the evaluator. Patients were randomized to one of two treatment conditions: (1) TAU - pharmacotherapy freely chosen by the clinician (n=23) and (2) TAU+IPT (n=17). Assessments were performed at weeks 8, 12, 19 and 24. Changes in the estimated means of the Hamilton Depression Rating Scale score were the primary outcome measure. Secondary outcomes included patient-rated scales and quality of life scales. We used a linear mixed model to compare changes over time between the two groups.

Results: Both treatments lead to improvements in depressive symptoms from baseline to week 24 with no significant between group differences in either primary: TAU (mean difference: 4.57; CI95%: 0.59-8.55; d=0.73) vs. IPT+TAU (mean difference: 5.86, CI95%: 1.50-10.22; d=0.93) or secondary outcomes.

Limitations: Our relatively small sample limits our ability to detect differences between treatments.

Conclusions: Both treatments lead to equal improvements in depressive symptoms. We found no evidence to support adding IPT to pharmacotherapy in patients with TRD.

Trial registration: ClinicalTrials.gov-NCT01896349.

Keywords: Depression; Interpersonal psychotherapy; Randomized pragmatic clinical trial; Treatment-resistant depression.