Exploratory factor analysis of two measures of posttraumatic stress disorder (PTSD) symptoms in a non-clinical sample of college students

This study investigated the psychometric structure of two widely utilized measures of posttraumatic symptoms in a primarily Caucasian non-clinical sample. Given the prevalence of trauma exposure in non-referred samples, measurement of resulting symptoms is a critical issue. Exploratory factor analysis was utilized to assess and compare the factor structure of the Impact of Event Scale [IES; Horowitz, M., Wilner, N., & Alvarez, W. (1979). Impact of Event Scale: a measure of subjective stress. Psychosomatic Medicine, 41, 209-218] and the Mississippi Scale for Posttraumatic Stress Disorder, Civilian version [MIS-Civ; Vreven, D. L., Gudanowski, D. M., King, L. A., & King, D. W. (1995). The Civilian Version of the Mississippi PTSD Scale-a psychometric evaluation. Journal of Traumatic Stress, 8, 91-109] in a sample of college students reporting exposure to potentially traumatic events. The psychometric structure of the IES was largely consistent with the two-factor structure widely reported in the literature, while the structure of the MIS-Civ varied considerably in this sample. Notably, non-clinical samples tended to report fewer social and occupational dysfunction than clinical samples predominantly utilized in PTSD research. Implications for use of these instruments in screening samples are discussed.