In our study, we assessed PTSD symptoms and, in most cases, continuing dissociative symptoms with the Clinician-Administered PTSD Scale. Dissociative symptoms at or near the time of injury were assessed with the Peritraumatic Dissociation Scale (3). We reduced some of the potential confounds that Dr. O’Donnell et al. were concerned about by excluding individuals who were intoxicated at the time of injury or had signs of traumatic brain injury. Interviews were conducted within a time frame that was similar to that of Dr. O’Donnell et al. While most of our subjects did receive intravenous narcotics during rescue and/or early during their admission, this did not lead to high rates of endorsement of dissociative criteria for acute stress disorder (16% met the criteria). Of the nine subjects we diagnosed with acute stress disorder in whom dissociation was assessed with the Peritraumatic Dissociation Scale and the Clinician-Administered PTSD Scale, only one would have met the criteria for acute stress disorder based solely on continuing dissociation assessed with the Clinician-Administered PTSD Scale. Therefore, it appears that peritraumatic dissociation does not necessarily persist into the first or second week after trauma. The rationale for emphasizing dissociation among the diagnostic criteria for acute stress disorder was based on studies of initial reactions to trauma (4). Lack of inclusion of information about the peritraumatic period would likely lead to underdiagnosis of acute stress disorder.