Extending Prolonged Exposure for Veterans With Posttraumatic Stress Disorder: When Is Enough Really Enough?

Program evaluation data from 451 veterans treated with at least four sessions of prolonged exposure (PE) within a U.S. Department of Veterans Affairs outpatient posttraumatic stress disorder program were examined to explore to what degree change by Session 8 predicted achieving meaningful change (MC; 50% reduction on the Post traumatic Stress Disorder Symptom Scale-Self-Report IPSS-SR]) after Session 8. The overall MC rate was 33.4%. A survival analysis determined the number of sessions required to achieve MC on the PSS-SR had a modal number of nine sessions. Logistic regressions found that younger veterans and those from more recent wars were more likely to achieve MC than the rest of the sample. An analysis of a subset of 156 patients who had more than eight sessions, had not achieved MC by Session 8, and had a Session 8 PSS-SR available found that those who had a reduction of at least 10% on the PSS-SR by Session 8 (71 patients) had a 42.3% rate of MC, while only 7.1% of the 85 patients with a less than 10% reduction by Session 8 went on to achieve MC. Approximately 636 post-Session 8 clinician hours were spent treating these 85 patients with PE to have only 6 achieve MC. These outcomes suggest that patients without an at least 10% reduction on the PSS-SR by Session 8 are unlikely to achieve MC with additional PE sessions; therefore, alternate treatments or augmentation of PE should be considered.