Uniformity of evidence-based treatments in practice? Therapist effects in the delivery of cognitive processing therapy for PTSD.

Abstract

Various factors contribute to the effective implementation of evidence-based treatments (EBTs). In this study, cognitive processing therapy (CPT) was administered in a Veterans Affairs (VA) posttraumatic stress disorder (PTSD) specialty clinic in which training and supervision were provided following VA implementation guidelines. The aim was to (a) estimate the proportion of variability in outcome attributable to therapists and (b) identify characteristics of those therapists who produced better outcomes. We used an archival database of veterans (n = 192) who completed 12 sessions of CPT by therapists (n = 25) who were trained by 2 nationally recognized trainers, 1 of whom also provided weekly group supervision. Multilevel modeling was used to estimate therapist effects, with therapists treated as a random factor. The supervisor was asked to retrospectively rate each therapist in terms of perceived effectiveness based on supervision interactions. Using single case study design, the supervisor was interviewed to determine what criteria she used to rate the therapists and emerging themes were coded. When initial level of severity on the PTSD Checklist (PCL; McDonald & Calhoun, 2010; Weathers, Litz, Herman, Huska, & Keane, 1993) was taken into account, approximately 12% of the variability in the PCL at the end of treatment was due to therapists. The trainer, blind to the results, identified the following characteristics and actions of effective therapists: effectively addressing patient avoidance, language used in supervision, flexible interpersonal style, and ability to develop a strong therapeutic alliance. This study adds to the growing body of literature documenting the importance of the individual therapist as an important factor in the change process.