Journal of Traumatic Stress, Vol. 19, No. 5, October 2006, pp. 639–651 ( C  2006) Low Predictive Power of Peritraumatic Dissociation for PTSD Symptoms in Accident Survivors Lutz Wittmann, Hanspeter Moergeli, and Ulrich Schnyder Department of Psychiatry, University Hospital, Zurich, Switzerland To test the predictive power of peritraumatic dissociation for the development of psychopathology, the authors assessed symptoms of peritraumatic dissociation (Peritraumatic Dissociative Experiences Questionnaire; PDEQ), posttraumatic stress disorder (Clinician-Administered PTSD Scale; CAPS), anxiety and depression (Hospital Anxiety and Depression Scale; HADS) in a sample of 214 accident victims 5 days postaccident (T1). Six months later (T2), CAPS and HADS were administered again. Acute stress disorder (ASD) and PTSD symptom levels were surprisingly low. In sequential regression analyses, initial reexperiencing and hyperarousal significantly predicted PTSD symptom level (T2) over several possibly confounding variables controlled for. Peritraumatic dissociation explained less than 3% of variance. For PTSD scores, 38% overall variance explanation was obtained; the variance for HADS scores was low. Possible explanations for the low-predictive power of peritraumatic dissociation for posttraumatic psychopathology in the sample are discussed. The advent of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV; American Psy- chiatric Association, 1994) has augmented the diagnosis of posttraumatic stress disorder (PTSD) by introducing the diagnosis of acute stress disorder (ASD). Apart from the duration criterion, the main difference between these two diagnostic entities is the cluster of dissociative symptoms in ASD. The DSM-IV defines dissociation as symptoms of emotional numbing, reduction in awareness of the sur- roundings, derealization, depersonalization, and dissocia- tive amnesia, occurring while or after experiencing the dis- tressing event. Survivors of potentially traumatic events fre- quently report peritraumatic dissociative experiences, i.e., dissociation during or immediately after a traumatic event (Bryant & Harvey, 1997). A recent meta-analysis pointed This study was supported by the Swiss National Science Foundation (Project 32–053736.98). Correspondence concerning this article should be addressed to: Lutz Wittmann, Department of Psychiatry, University Hospital, Culmannstrasse 8, CH-8091 Zurich, Switzerland. E-mail: lutz.wittmann@usz.ch. C  2006 International Society for Traumatic Stress Studies. Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/jts.20154 to the importance of peritraumatic dissociation for the early identification of trauma survivors who later go on to develop PTSD (Ozer, Best, Lipsey, & Weiss, 2003). In this meta-analysis, peritraumatic dissociation proved to be the strongest of seven predictors of later PTSD based on 16 positive findings. In recent years, however, an increasing number of pub- lications cast doubt on the importance of peritraumatic dissociative symptoms for the prediction of PTSD symp- toms. Several studies, appearing after 2000 and therefore not included in the meta-analysis by Ozer et al. (2003), suggested viewing the relationship between peritraumatic dissociation and posttraumatic stress symptoms as an arti- fact of confounding variables (Gershuny, Cloitre, & Otto, 2003; Holeva & Tarrier, 2001; Mayou, Bryant, & Ehlers, 639