A brief Acceptance and Commitment Therapy intervention for depression: A randomized controlled trial with 3-year follow-up for the intervention group

This study examined the outcomes of a brief Acceptance and Commitment Therapy (ACT) intervention for depression delivered by novice therapists. Participants (N = 115) were randomized either to the brief (six sessions) ACT or to a waitlist control condition (WLC). Outcomes were assessed with diagnoses of depressive episodes (ICD-10) and questionnaires. After the 6-week intervention, diagnostic remission rates were 60% in the ACT and 22% in the control group. Further, 70% of the ACT participants were classified as either recovered or improved. The post-measurement between-group effect size for depression symptoms was large and favored the ACT group (BDI-II, d = 1.25). At the 3-year follow-up, the within-group effect sizes were encouraging (d = 1.11–1.77). A 6-h ACT intervention delivered by novice therapists can lead to improvement in approximately 60–70% of depressed clients.