The role of evidence-based therapy relationships on treatment outcome for adults with trauma: A systematic review.

OBJECTIVE: The purpose of this paper was to systematically review and synthesize the empirical literature on the effects of evidence-based therapy relationship (EBR) variables in the psychological treatment for adults who experienced trauma-related distress.

METHOD: Studies were identified using comprehensive searches of PsycINFO, Medline, Published International Literature on Traumatic Stress, and Cumulative Index to Nursing and Allied Health Literature databases. Included in the review were articles published between 1980 and 2015, in English that reported on the impact of EBRs on treatment outcome in clinical samples of adult trauma survivors.

RESULTS: Nineteen unique studies met inclusion criteria. The bulk of the studies were on therapeutic alliance and the vast majority found that alliance was predictive of or associated with a reduction in various symptomotology. Methodological concerns included the use of small sample sizes, little information on EBRs beyond alliance as well as variability in its measurement, and non-randomized assignment to treatment conditions or the lack of a comparison group.

CONCLUSIONS: More research is needed on the roles of client feedback, managing countertransference, and other therapist characteristics on treatment outcome with trauma survivors. Understanding the role of EBRs in the treatment of trauma survivors may assist researchers, clinicians, and psychotherapy educators to improve therapist training as well as client engagement and retention in treatment.