Acceptance and commitment therapy as a web-based intervention for depressive symptoms: randomised controlled trial.

BACKGROUND Depression is a highly prevalent disorder, causing a large burden of disease and substantial economic costs. Web-based self-help interventions seem promising in promoting mental health. AIMS To compare the efficacy of a guided web-based intervention based on acceptance and commitment therapy (ACT) with an active control (expressive writing) and a waiting-list control condition (Netherlands Trial Register NTR1296). METHOD Adults with depressive symptoms from the general population were randomised to ACT (n = 82), expressive writing (n = 67) or waiting-list control (n = 87). The main outcome was reduction in depressive symptoms assessed with the Center for Epidemiological Studies - Depression scale. RESULTS Significant reductions in depressive symptoms were found following the ACT intervention, compared with the control group (Cohen's d = 0.56) and the expressive writing intervention (d = 0.36). The effects were sustained at 6-month and 12-month follow-up. CONCLUSIONS Acceptance and commitment therapy as a web-based public mental health intervention for adults with depressive symptoms can be effective and applicable.