Efficacy of a two-session repetitive negative thinking-focused acceptance and commitment therapy (ACT) protocol for...

This parallel randomized controlled trial aimed to evaluate the effect of acceptance and commitment therapy (ACT) focused on disrupting repetitive negative thinking (RNT) versus a waitlist control (WLC) in the treatment of depression and generalized anxiety disorder (GAD). Forty-eight participants with a main diagnosis of depression and/or GAD were allocated by means of simple randomization to a 2-session RNT-focused ACT intervention or to the WLC. The primary outcomes were emotional symptoms as measured by the Depression, Anxiety, and Stress Scales-21. Process outcomes included ACT- and RNT-related measures: general RNT, experiential avoidance, cognitive fusion, values, and generalized pliance. At the 1-month follow-up, linear mixed effects models showed that the intervention was efficacious in reducing emotional symptoms (d = 2.42, 95% confidence interval [1.64, 3.19]), with 94.12% of participants in the RNT-focused ACT condition showing clinically significant change in the Depression, Anxiety, and Stress Scales-21 total scores versus 9.09% in the WLC condition (70% vs. 8% in intention-to-treat analysis). The intervention effects were maintained at the 3-month follow-up. No adverse events were found. A very brief RNT-focused ACT intervention was highly effective in the treatment of depression and GAD. (PsycInfo Database Record (c) 2020 APA, all rights reserved).