A comparison of the CAPS-5 and PCL-5 to assess PTSD in military and veteran treatment-seeking samples

Resick, P. A., Straud, C. L., Wachen, J. S., LoSavio, S. T., Peterson, A. L., McGeary, D. D., Young-McCaughan, S., Taylor, D. J., & Mintz, J., for the STRONG STAR Consortium and the Consortium to Alleviate PTSD
Jun 24, 2023

European Journal of Psychotraumatology, 14(2), Article 2222608. 

Background: This study was an examination of the puzzling finding that people assessed for symptoms of posttraumatic  stress disorder (PTSD) consistently  score higher  on  the self-report PTSD Checklist for DSM-5 (PCL-5) than the Clinician-Administered PTSD Scale for DSM-5 (CAPS- 5). Both scales purportedly  assess PTSD  severity with the  same number  of  items, scaling,  and scoring range, but differences in scores between measures make outcomes difficult to decipher.
Objective: The purpose of this study was to examine several possible psychometric reasons for the discrepancy in scores between interview and self-report.
Method: Data were combined from four clinical trials to examine the baseline and posttreatment 
assessments of treatment-seeking active duty military personnel and veterans.
Results: As in previous studies, total scores were higher on the PCL-5 compared to the CAPS-5 at 
baseline and posttreatment. At baseline, PCL-5 scores were higher on all 20 items, with small to large differences  in  effect  size.  At posttreatment, only three items were not significantly different. Distributions of item responses and wording of scale anchors and items were examined as possible explanations of the difference between measures. Participants were more likely to use the full range of responses on the PCL-5 compared to interviewers.
Conclusions: Suggestions for improving the congruence between these two scales are discussed. 
Administration of interviews by trained assessors can be resource intensive, so it is important 
that those assessing PTSD severity are afforded confid  nce in the equivalence of their assessment of
PTSD regardless of the assessment method used.