The D*Phase-study: Comparing short-term psychodynamic psychotherapy and cognitive behavioural therapy for major depressive disorder in a randomised controlled non-inferiority trial.

Background: Given both the large volume and manifold preferences of patients with depression, the availability of various effective treatments is important. Psychodynamic psychotherapy (PDT) has received less research in comparison to cognitive behavioural therapy (CBT) for major depressive disorder (MDD). This study aimed to establish whether short-term psychodynamic supportive psychotherapy (SPSP) is non-inferior to CBT in the treatment of MDD.

Methods: A non-inferiority trial was conducted in a Dutch mental health setting, with 290 patients randomised to receive 16 sessions of either CBT or SPSP, over eight weeks. Primary outcome was depressive symptom severity assessed using the self-rated Inventory of Depressive Symptomatology (IDS-SR). The non-inferiority margin was prespecified as a - 5 post-treatment difference on the IDS-SR. Secondary outcome measures were functional impairment caused by symptoms assessed using the Sheehan disability scale (SDS), and wellbeing measured by the Mental Health Continuum-Short Form (MHC-SF).

Results: Both intention-to-treat (baseline-adjusted mean difference 1.62, 95 % CI -1.82 to 5.05) and per-protocol analyses (mean difference 2.54; 95 % CI -0.63 to 5.72) showed SPSP to be non-inferior to CBT in reducing depressive symptoms. SPSP showed slightly but significantly higher remission rates and wellbeing scores.

Limitations: Patients opting for other therapies or medication did not take part in the trial. Follow-up measures or clinician-rated questionnaires were not included.

Conclusions: The findings support SPSP as a viable treatment option for MDD, expanding the available choices for patients and broadening treatment options.