Internet-based therapist-supported interpersonal psychotherapy for depression: A randomized controlled trial

Abstract

Background: Depression is a common disorder for which there are several treatments options including different psychological treatments. The aim of this study was to investigate the effects of internet-based interpersonal psychotherapy (IPT) for symptoms of depression in randomized controlled trial.

Methods: Following recruitment via advertisement a total of 113 participants with mild to moderate symptoms of depression were included and randomized to either a ten-week internet-based IPT with weekly therapist guidance or a waitlist control condition. The primary outcome was symptoms of depression measured weekly with the Montgomery Åsberg Depression Rating Scale (MADRS-S) and at pre- and post-treatment assessment with the Beck's Depression Inventory (BDI-II). Secondary outcomes were self-rated quality of life and symptoms of generalized anxiety disorder. We also measured therapeutic alliance and treatment credibility. Outcomes were evaluated with a latent growth curve model (for MADRS-S) and robust linear regression models (for the other measures). The trial was conducted during the Covid-19 pandemic in the spring of 2021.

Results: Significant differences favoring the treatment group were found on three of the four outcomes: BDI-II, quality of life ratings, and ratings of generalized anxiety. Between-group effect sizes for these outcomes were moderate (BDI-II, quality of life) or small (generalized anxiety). The latent growth curve model did not indicate a significant difference on the weekly MADRS-S ratings. Exploratory analyses did not show an association between therapeutic alliance, treatment credibility and outcome.

Limitations: Missing data at post-treatment was high in the treatment group (37 %), though the missingness was not significantly related to observed ratings at pre-treatment or estimated trajectories during the treatment. Few participants completed all modules. The Covid-19 pandemic situation may have affected both effects and dropout rates.

Conclusions: Internet-based IPT can lead to significant improvements, though the reductions in symptoms of depression were not consistent across the two measures used. Completion rates and dropout patterns suggest a need for improved acceptability.

Trial registration: The trial was preregistered at Clinicaltrials.gov (Identifier: NCT04721678). Registered January 2021.https://clinicaltrials.gov/study/NCT04721678.

Keywords: Internet-delivery; Interpersonal psychotherapy; Major depression; Therapeutic alliance; Treatment credibility.