Testing the dimensionality of posttraumatic stress responses in young Chinese adult earthquake survivors: further evidence for "dysphoric arousal" as a unique PTSD construct.

Background: This study investigated an alternative five-factor diagnostic model for posttraumatic stress disorder (PTSD) symptoms, and tested external convergent and discriminant validity of the model in a young Chinese sample of earthquake survivors.

Methods: A total of 938 participants (456 women, 482 men) aged 15-20 years were recruited from a vocational school originally located in Beichuan County Town which was almost completely destroyed by the "Wenchuan Earthquake." The participants were administrated with the PTSD Checklist and the Hopkins Symptoms Checklist-25 12 months after the earthquake.

Results: The results of confirmatory factor analysis showed that the five-factor intercorrelated model (intrusion, avoidance, numbing, dysphoric arousal, and anxious arousal) fit the data significantly better than the four-factor numbing model proposed by King et al. (1998: Psychol Assess 10:90-96) and the four-factor dysphoria model proposed by Simms et al. (2002: J Abnorm Psychol 111:637-647). Further analyses indicated that four out of five PTSD factors yielded significantly different correlations with external measures of anxiety versus depression.

Conclusions: The findings provide further empirical evidence in favor of the five-factor diagnostic model of PTSD, and carry implications for the upcoming DSM-5.