Factor structure of posttraumatic stress disorder (PTSD) in persons with serious mental illness.

Trauma and posttraumatic stress disorder (PTSD) are common among individuals with serious mental illness (SMI; e.g., schizophrenia, schizoaffective disorder, bipolar disorder, treatment refractory major depressive disorder), with resultant functional impairment. Previous studies have not evaluated the factor structure of the PTSD Checklist (PCL) among persons with SMI. This study evaluated the factor structure of the PCL in two large SMI samples from public mental health treatment sectors screened for PTSD using the PCL. Four different models of PTSD were tested using confirmatory factor analyses. Results indicated that the DSM-5 4-factor model (intrusion, avoidance, numbing, and hyperarousal) had the best fit. Further, the DSM-5 4-factor model demonstrated measurement invariance. Results supported the suitability of the DSM-5 4-factor model of PTSD among people with SMI.