Mechanisms of change in mobile app-delivered acceptance and commitment therapy for posttraumatic stress disorder in China: a secondary analysis of a randomized controlled trial.

Background

Research has demonstrated the effectiveness of a mobile app-delivered Acceptance and Commitment Therapy (IACT) programme for individuals with posttraumatic stress disorder (PTSD) in their PTSD symptoms. However, there are still few studies on its mediating mechanism.

Objective

This secondary analysis aimed to examine whether six components of psychological flexibility - acceptance, present-moment awareness, self-as-context, cognitive defusion, valued living, and committed action - mediate the effects of an IACT programme for individuals with PTSD.Method: Data were obtained from a randomized controlled trial in which participants were assigned to an IACT condition (n = 78) or a waitlist control (WL; n = 67). Using a latent growth curve modelling approach with bias-corrected bootstrapped confidence intervals, changes in PTSD symptoms and psychological flexibility components were assessed at baseline (T1) and following each of six intervention modules (T2-T7).

Results

Relative to WL, the IACT group showed significantly greater improvements in both PTSD symptoms and all six flexibility components. Mediation analyses revealed that four processes - acceptance, self-as-context, cognitive defusion, and committed action - fully mediated the intervention's effects on PTSD outcomes, whereas valued living and present-moment awareness served as partial mediators.

Conclusions

These findings suggest that enhancing these components of psychological flexibility may be crucial for effective IACT treatment of PTSD.