Abstract
The Posttraumatic Stress Disorder (PTSD) Checklist for DSM-5 (PCL-5) is a widely used, self-report measure that is employed to assess PTSD symptom severity and determine the presence of probable PTSD in various trauma-exposed populations. The PCL-5 is often administered in clinical settings as a screening tool for PTSD, with a suggested cutoff score of 33 indicating a probable PTSD diagnosis. Recent research indicates that a higher cutoff may be required in psychiatric samples. In the present study, we aimed to determine the sensitivity and specificity of the PCL-5 in a Canadian outpatient psychiatric sample and establish an optimal cutoff score for detecting probable PTSD in this sample. Participants were 673 individuals who reported a history of trauma exposure and were assessed using a semistructured interview and self-report measures. Individuals diagnosed with PTSD (N = 193) reported a mean PCL-5 score of 56.57, whereas individuals without PTSD (N = 480) reported a mean score of 33.56. A score of 45 was determined to be the optimal cutoff score in this sample, balancing sensitivity and specificity while detecting a probable diagnosis of PTSD. Consistent with findings in other psychiatric samples, these findings indicate that in an outpatient psychiatric sample with a history of exposure to a variety of trauma types, a higher cutoff score is required to determine probable PTSD. In addition, given the estimated rate of false positives even with a higher cutoff, follow-up diagnostic assessments are recommended.