Concordance in PTSD symptom change between DSM-5 versions of the Clinician-Administered PTSD Scale (CAPS-5) and PTSD Checklist (PCL-5).

The Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5) versions of the Clinician-Administered PTSD Scale (CAPS-5) and PTSD Checklist (PCL-5) are widely used PTSD measures. Researchers and clinicians routinely use both measures in tandem to quantify symptom change, despite substantive instrumentation differences beyond administration modality, and absent a theoretical rationale or differential hypotheses for the two measures. The degree to which these measures provide comparable estimates of symptom change is unknown. This study examined concordance in change between CAPS-5 and PCL-5 scores over time. Participants were male veterans (N = 198) randomly assigned to one of two group PTSD treatments. We administered both the CAPS-5 and PCL-5 at baseline, midtreatment, immediately posttreatment, and 3-, 6-, and 12-month posttreatment. Results indicated that CAPS-5 and PCL-5 scores changed over time in a similar manner, as evidenced by generally parallel repeated-measures effect sizes, highly correlated slopes of change (r = .878), and similar associations with improvements in measures of depression and psychosocial functioning. However, the two measures did not produce identical estimates of symptom change. Estimates of symptom improvement were somewhat less concordant at posttreatment follow-up assessments; by the 12-month posttreatment assessment, changes in CAPS-5 scores from baseline indicated somewhat greater symptom improvement than changes in PCL-5 scores (CAPS-5 ESsg = -0.67, PCL-5 ESsg = -0.53). Collectively, results indicate that CAPS-5 and PCL-5 scores produce similar but not identical estimates of PTSD symptom change. Thus, although PCL-5 scores closely approximate symptom change estimated by CAPS-5 scores, the two measures are not interchangeable. (PsycInfo Database Record (c) 2022 APA, all rights reserved).