Psychometric evaluation of trauma and posttraumatic stress disorder assessments in persons with severe mental illness

Interrater reliability, internal consistency, test-retest reliability, and convergent validity were examined for the Trauma History Questionnaire (THQ), the Clinician-Administered Posttraumatic Stress Disorder (PTSD) Scale (CAPS), and the PTSD Checklist (PCL) in 30 clients with severe mental illnesses. Interrater reliability for the THQ and CAPS was high, as was internal consistency of CAPS and PCL subscales. The test-retest reliability of the THQ was moderate to high for different traumas. PTSD diagnoses on the CAPS and PCL showed moderate test-retest reliability. Lower levels of test-retest reliability for PTSD diagnoses were related to psychosis diagnoses and symptoms. However, when more stringent criteria for PTSD were used on the CAPS, it had excellent test-retest reliability across all clients. CAPS and PCL diagnoses of PTSD showed moderate convergent validity. The results support the reliability of trauma and PTSD assessments in clients with severe mental illness.