Therapeutic alliance in psychological therapy for posttraumatic stress disorder: A systematic review and meta-analysis

Background Therapeutic alliance is a key element of successful therapy. Despite being particularly relevant in people with posttraumatic stress disorder (PTSD), due to fear, mistrust and avoidance, there has not yet been a comprehensive systematic review of therapeutic alliance in this population. This review explored (a) variables which may predict alliance and (b) whether alliance predicts PTSD outcomes. Method Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, the review identified 34 eligible studies. Studies were subjected to a quality assessment. Predictors of alliance were considered in a narrative synthesis. Twelve studies were entered into a meta-analysis of the association between therapeutic alliance and PTSD outcomes. Results There was some evidence for individual variables including attachment, coping styles and psychophysiological variables predicting the alliance. Therapy variables did not predict alliance. The therapeutic alliance was found to significantly predict PTSD outcomes, with an aggregated effect size of r = -.34, across both in-person and remote therapies. Limitations Included studies were restricted to peer-reviewed, English language studies. Quality of included studies was mostly rated weak to moderate, primarily reflecting issues with selection bias in this area of research. Conclusions This is the first review to demonstrate that therapeutic alliance is a consistent predictor of PTSD outcomes, in both in-person and remote therapies, and the effect appears at least as strong as in other populations. This is of relevance to clinicians working with traumatized populations. The review identified a need for further research to determine variables predicting alliance in therapy for PTSD.