Advancing Depression Treatment: A Randomized Controlled Trial of Dynamic Interpersonal Therapy Versus CBT and Pharmacotherapy on Symptoms, Sleep, and Cognition

This randomized controlled trial (RCT) investigates the efficacy of Dynamic Interpersonal Therapy (DIT) compared to Cognitive Behavioral Therapy (CBT) and pharmacotherapy in treating major depressive disorder (MDD), focusing on depressive symptoms, sleep quality, and cognitive functioning. Despite the established efficacy of CBT and pharmacotherapy, prior research has largely overlooked DIT’s potential, particularly its long-term effects, and impacts beyond symptom reduction, with limited comparisons across these domains. This study addresses these gaps through a novel three-arm RCT involving 225 participants randomly assigned to 16-week DIT, CBT, or pharmacotherapy interventions across five primary care centers in Iran (Tehran, Tabriz, Shiraz, Isfahan, and Mashhad), with follow-ups at 6 and 12 months. Assessments utilized the Hamilton Depression Rating Scale (HAM-D-17), Pittsburgh Sleep Quality Index (PSQI), and Stroop Test, analyzed via Mixed-Design ANOVA. Findings revealed significant short-term improvements in all groups, but only DIT maintained stable reductions in depressive symptoms (38% decrease) and sleep disturbances (45% improvement) at follow-up. DIT also demonstrated superior and sustained improvements in cognitive inhibition, attention, flexibility, and processing speed compared to CBT and pharmacotherapy. While CBT showed moderate long-term stability, pharmacotherapy was associated with symptom relapse and diminished cognitive gains. These findings position DIT as a pioneering, durable treatment option, emphasizing its holistic benefits and challenging the dominance of symptom-focused approaches, with implications for advancing depression care.