Effect of third-wave cognitive behavioral therapy in adults with acquired brain injury: A systematic review and meta-analysis of randomized controlled trials.

OBJECTIVE: Third-wave cognitive behavioral therapies may be beneficial for relieving psychological symptoms in adults with acquired brain injury, but no comprehensive overview and pooled estimate of their effects exist. We conducted a systematic review and meta-analysis of randomized controlled trials to address this gap. METHOD: Three databases (Pubmed, APA PsycInfo, and the Cochrane Library) were searched. Included studies were quality-assessed and frequentist and Bayesian analytical strategies were employed for data synthesis and interpretation. Effects were evaluated for outcomes reported in ≥7 studies, and potential moderating influences of study characteristics were explored when available in ≥10 studies. RESULTS: Twenty-eight randomized controlled trials (N = 1,869) were included. Statistically significant effects at postintervention were observed for depression (K = 20, Hedges's g = 0.49, 95% CI [0.17, 0.81]), anxiety (K = 13, g = 0.48, 95% CI [0.01, 0.95]), mindfulness skills (K = 7, g = 0.33, 95% CI [0.12, 0.54]), and health-related quality of life (QoL; K = 11, g = 0.62, 95% CI [0.21, 1.03]). At follow-up, effects were significant for depression (K = 12, g = 0.42, 95% CI [0.12, 0.72]), psychological flexibility (K = 4, g = 0.47, 95% CI [0.13, 0.81]), and stress (K = 3, g = 0.39, 95% CI [0.02, 0.77]). The observed effects were generally smaller after adjusting for outliers (±2 SDs; g = 0.23-0.29). After adjusting for outliers, Bayesian meta-analysis provided strong to very strong support (Bayes factors values: 16-90) for effects on depression at posttreatment and follow-up and QoL at posttreatment. The only moderator analysis reaching statistical significance was for study quality, with higher values being associated with smaller effects on anxiety and QoL. CONCLUSION: Third-wave cognitive behavioral therapies are likely to be beneficial for relieving psychological symptoms in adults with acquired brain injury, particularly depression and QoL. However, more research is needed to establish robust evidence for their efficacy and clinical relevance. (PsycInfo Database Record (c) 2026 APA, all rights reserved).