Intensive Short-Term Dynamic Psychotherapy (ISTDP) has an increasing amount of evidence regarding its efficacy across various psychiatric conditions and specifically with depression. The aim of this study is to replicate the findings of controlled research by examining the effects of ISTDP in the treatment of depression in a large naturalistic sample, and also to explore the mediating role of unlocking the unconscious in this treatment. Healthcare costs were also explored. Data were collected from a naturalistic study conducted at the Centre for Emotions and Health, Halifax, Nova Scotia, Canada, between 1999 and 2007. A sample of 195 patients' self-reported levels of depression, measured by the depression subscale of the Brief Symptom Inventory (BSI), and interpersonal problems, measured by the Inventory of Interpersonal Problems-32 (IIP-32), were analyzed using mixed-effects models. The analysis revealed a significant and large effect of ISTDP on both depression (within-group Cohen's d = 1.02, 95% CI [0.75, 1.26]) and interpersonal problems (within-group Cohen's d = 1.17, 95% CI [0.89, 1.46]). The process of unlocking the unconscious emerged as a significant mediator of treatment outcomes for both depression (between-group Cohen’s d = 0.60, 95% CI [0.16, 1.07]) and interpersonal problems (between-group Cohen’s d = 0.47, 95% CI [-0.05, 0.95]). Reductions in costs regarding physician (p = 0.07) and hospital costs (p &lt; 0.05) were observed. These findings support the efficacy of ISTDP in treating depression and highlight the importance of unlocking the unconscious among patients with depression.

Intensive Short-Term Dynamic Psychotherapy for depression: Treatment effectiveness and effects of unlocking the unconscious