VALIDITY AND RELIABILITY OF PERSIAN VERSIONS OF PERITRAUMATIC DISTRESS INVENTORY (PDI) AND DISSOCIATIVE EXPERIENCES SCALE (DES)

Background: Posttraumatic stress disorder (PTSD) is one of the most commonly observed stress-related conditions following a motor vehicle accident, and its effective prevention is a high health-care priority. Although the reliable and valid Dissociative Experience Scale (DES) as the gold-standard instrument to quantify the frequency of self-reported dissociative experiences, and as much the Peritraumatic Distress Inventory (PDI; as a self-report measure-validated in several languages) are useful for identifying adults at risk of developing acute and chronic posttraumatic stress disorder (PTSD), they have not been validated in Iran and their predictive values remain unknown in this population. Objective: To assess the reliability and validity of the Persian version of Dissociative Experience Scale (DES) and the Peritraumatic Distress Inventory (PDI). Method: We included 43 male survivors of fatal motor vehicle accidents. The participants were assessed by PDI and DES, and were retested by DES, and assessed by Mississippi Scale for PTSD in three intervals of immediately after, one month and three months after the event. Results: The DES was significantly correlated with PTSD. Reliability analysis revealed a Cronbach's alpha coefficient of 0.87. The Intraclass Correlation Coefficient for test-retest analysis was 0.87. The PDI was not significantly correlated with PTSD and was borderline and not significantly correlated with DES. Reliability analysis revealed a Cronbach's alpha coefficient of 0.73. Conclusion: Our results suggest that Persian versions of PDI and DES showed a desirable psychometric applicability, except for predictive criterion validity for PDI. In regard to predictive validity, DES but not PDI, might be good instruments to use as a reliable screening tool for future PTSD at least in the initial week after MVA.