Psychometric properties of the PTSD Checklist for DSM-5 in a sample of trauma exposed mental health service users.

: PTSD self-report measures are frequently used in mental health services but very few have been evaluated in clinical samples that include civilians. The PCL-5 was developed to assess for DSM-5 PTSD. : The aim of this study was to evaluate the psychometric properties of the PCL-5 in a sample of trauma-exposed mental health service users who were evidencing symptoms of PTSD. : Reliability and validity of the PCL-5 were investigated in a sample of 273 participants who reported past diagnosis for PTSD or who had screened positively for traumatic stress symptoms. Diagnostic utility was evaluated in comparison to the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5). : The PCL-5 demonstrated high internal consistency, good convergent and divergent validity, acceptable stability and good diagnostic utility. However, operating characteristics differed from those found in other samples. Scores of 43-44 provided optimal efficiency for diagnosing PTSD. A post hoc regression analysis showed that depression explained more of the variance in PCL-5 total score than the CAPS-5. : Whilst the PCL-5 is psychometrically sound it appears to have difficulty differentiating self-reported depression and anxiety symptoms from PTSD in trauma-exposed mental health service users and clinicians should take care to assess full symptomatology when individuals screen positively on the PCL-5. Clinicians and researchers should also take care not to assume that operating characteristics of self-report PTSD measures are valid for mental health service users, when these have been established in other populations.