Brief summary
This meta-analysis explores the effectiveness of acceptance and commitment therapy (ACT) for depression in both culturally diverse contexts and varying intervention focuses. Data were drawn from 263 randomised controlled trials (RCTs) with over 21,800 participants to evaluate ACT’s impact on depressive symptoms when depression was either the primary or a secondary target. The findings contribute to understanding ACT’s transdiagnostic flexibility and its potential advantages over other interventions.
Key findings
ACT reduced depression symptoms significantly, yielding strong average reductions (g = 0.88). The effect was larger when depression was the primary focus (g = 1.18) compared to a secondary focus (g = 0.67).
ACT demonstrated stronger incremental effects over passive control conditions (waitlists) than over active controls (e.g., other psychotherapies). When depression was targeted, ACT’s superiority was more pronounced against passive controls (g = 1.10) and less so against active controls (g = 0.35).
The meta-analysis revealed significant cultural differences in ACT outcomes. Effects tended to be stronger in studies conducted outside of Western regions, especially in East Asia and the Middle East; however, these studies often had lower methodological quality scores.
High publication bias (favouring ACT) was observed, with smaller studies showing larger effects. Lower-quality studies were also associated with better outcomes.
Contextual factors, such as study design quality and therapeutic delivery methods, contributed to variability in findings.
Practice recommendations
Clinicians should consider using ACT even when depression is not the primary focus, as it provides measurable benefits across diverse treatment objectives. When implementing ACT internationally, therapists should adapt their approaches to cultural contexts, particularly in regions where evidence suggests stronger outcomes. Researchers and clinicians should prioritise high-quality, transparent methodologies to ensure reliable findings, including larger samples and rigorous trial designs.
ACT is effective compared to no treatment but shows modest advantages over other active treatments, supporting its integration within a portfolio of therapeutic options rather than as a singular solution.
Reference
Borgogna, N. C., Owen, T., Spencer, S. D., Jo, D., Jafari, M., Vaughn, J., … Hill, B. D. (2026). A cross-cultural incremental effects meta-analysis of acceptance and commitment therapy for depression: does targeting depression even matter? Cognitive Behaviour Therapy. (Accepted for publication).
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