Predictors for Excellent Versus Partial Response to Prolonged Exposure Therapy: Who Needs Additional Sessions?

Abstract

In practice, the duration of psychotherapy is determined by the patient's response to treatment. Identifying predictors for treatment responses is of great clinical utility to guide clinicians in their treatment planning. Demographic characteristics, trauma history, comorbidity, and early reduction of posttraumatic stress disorder (PTSD) symptoms were examined as predictors of excellent versus partial response to prolonged exposure therapy (PE) for PTSD. Participants were 96 female assault survivors with chronic PTSD who received at least eight PE sessions with or without cognitive restructuring. Participants were classified as excellent responders (n = 27) or partial responders (n = 69) based on whether they achieved at least 70% improvement in self-reported PTSD severity on the PTSD Symptom Scale-Self-Report at the end of Session 8. Excellent responders terminated therapy after Session 9, and partial responders were offered up to three additional sessions. Logistic regression was conducted to investigate predictors of response to PE. Results showed that prior interpersonal violence and comorbid alcohol use disorder were associated with partial response. Comorbid depressive disorder and early PTSD symptom reduction were associated with excellent response. Being treated by a cognitive behavioral therapy expert predicted higher excellent response for patients with a history of prior interpersonal violence. The model accounted for 56.6% of the variance in treatment response and correctly predicted responder status for 83.3% of the sample. These findings contribute to the field's understanding of factors that predict or moderate response to PE and have implications for treatment planning.