Fidelity to the Cognitive Processing Therapy Protocol: Evaluation of Critical Elements.

The contributions of individual therapy elements to the overall efficacy of evidence-based practices for the treatment of posttraumatic stress disorder (PTSD) are not well-understood. This study first examined the extent to which theoretically important treatment components of Cognitive Processing Therapy (CPT; i.e., skill in Socratic questioning; prioritizing assimilation; attention to practice assignments; emphasis on expression of natural affect) were successfully administered across the course of therapy for 68 PTSD-positive survivors of interpersonal trauma. Therapist fidelity in the administration of these four elements was evaluated in 533 taped CPT sessions of study participants included in one of two randomized controlled CPT treatment trials. Second, we examined therapist fidelity to these components as a predictor of session-to-session PTSD and depression symptom change. Third, follow-up analyses examined the influence of high therapist competence for these four components across an entire course of therapy on symptom change from pre- to posttreatment. Results showed consistently high adherence and more variable competence for these four treatment components. There were no significant effects of therapist fidelity on session-to-session symptom change. However, results showed that overall high therapist competence for "skill in Socratic questioning" and "prioritizing assimilation before overaccommodation" were related to greater client improvement in PTSD severity, but "attention to practice assignments" and "emphasis on expression of natural affect" were not. Overall competence ratings for the four components were not significantly associated with improvement in depressive symptoms. Findings contribute to increased understanding of the relationship between the key treatment components of CPT and symptom change.