UC San Diego

We calculated the reliable change index (RCI) and clinically significant change (CSC) values for two widely used measures of posttraumatic stress disorder (PTSD): The Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) and the PTSD Checklist for DSM-5 (PCL-5) and examined how symptom changes at these thresholds related to improvements in psychosocial functioning. We used data from three independent samples of male military veterans, including two randomized controlled trials for PTSD (N = 198 for Sample 1 and N = 102 for Sample 2) and a cross-sectional study of primary care patients (N = 228). For Sample 1, within-person change in CAPS-5 and PCL-5 scores of ≥ 13 and 15, respectively, was indicative of reliable change. For Sample 2, within-person change in CAPS-5 and PCL-5 scores of ≥ 12 and 18, respectively, was indicative of reliable change. Scores of ≤ 8 and 28 on the CAPS-5 and PCL-5, respectively, indicated a participant is more likely to belong to the non-PTSD population than the PTSD population (i.e., clinically significant change) in both Samples 1 and 2. Participants who exhibited reliable or CSC reported significantly better psychosocial functioning at all posttreatment assessments than those who did not. Results provide thresholds for identifying clinically meaningful PTSD symptom change using these measures. Care should be taken to interpret these values appropriately and relative to numerous other definitions for meaningful symptom change. (PsycInfo Database Record (c) 2022 APA, all rights reserved).