The factor structure of posttraumatic stress disorder: A literature update, critique of methodology, and agenda for future research

We present an update of recent literature (since 2007) exploring the factor structure of posttraumatic stress disorder (PTSD) symptom measures. Research supporting a four-factor emotional numbing model and a four-factor dysphoria model is presented, with these models fitting better than all other models examined. Variables accounting for factor structure differences are reviewed, including PTSD query instructions, type of PTSD measure, extent of trauma exposure, ethnicity, and timing of administration. Methodological and statistical limitations with recent studies are presented. Finally, a research agenda and recommendations are offered to push this research area forward, including suggestions to validate PTSD's factors against external measures of psychopathology, test moderators of factor structure, and examine heterogeneity of symptom presentations based on factor structure examination.

► Across the literature, the best fitting factor structure for PTSD is based on the emotional numbing and dysphoria PTSD models. ► Several moderators of PTSD's factor structure have been revealed, including assessment and measurement conditions, war exposure, culture, gender and timing of administration. ► Numerous methodological and statistical limitations are apparent with studies reporting on the factor structure of PTSD.