To the Editor: Since our overall conclusion was that the DSM-IV approach to posttraumatic syndromes should be reevaluated in its entirety (in agreement with most authors), we welcome the opportunity of constructive dialogue; it is unfortunate that there is not space for a more detailed response. A number of disorders have been extensively revised or eliminated throughout the evolution of DSM. We proposed eliminating the new diagnosis of acute stress disorder on the basis of a review of all studies available at the time of writing that suggested it makes little conceptual or clinical sense to regard the first month of a posttraumatic syndrome as a separate disorder. Instead, a single posttraumatic stress syndrome could be created with acute and chronic designations, incorporating dissociative symptoms in a way that recognizes but does not require their presence to make a diagnosis. Our empirical reviews clearly demonstrated that the acute stress disorder diagnosis fails to recognize a significant proportion of patients with symptoms and disability in the first month after trauma who do not have dissociative symptoms and therefore does not accomplish its original intention.

All five of the preceding letters came from authors who have a particular interest in dissociative phenomenology and who have made important contributions in this area of research. Most emphasize the role of dissociative symptoms as a predictor of clinical severity and longitudinal course. Since these findings are well established and were cited in our article, we find no point of disagreement. Unfortunately, none addresses our primary argument, which was that predictor status is not sufficient to identify a core feature of a syndrome. Once examined empirically, our review showed that dissociative symptoms have high specificity but unacceptably low sensitivity to function as a core feature. In addition, most of the letters’ authors confound the study of acute predictors of chronicity with the necessity of having two separate diagnoses.

The more recent studies cited by several authors support our primary conclusions. For example, the recent study of Brewin et al. (1999) was cited as a refutation of our proposal. In fact, a careful reading of this excellent article supports our interpretation of the literature: when dissociative symptoms were required diagnostically, sensitivity was lowered while specificity was increased. Brewin et al. also concluded that they had "failed to find a unique role for dissociative symptoms." The fact that this complex study was presented as unequivocal suggests that much discussion is needed for the field to reach agreement on the interpretation of empirical findings in this area.

Dr. Spiegel and colleagues apparently misunderstood several aspects of our review. We will respond to each point separately.

1. We agree that peritraumatic dissociative symptoms often differ from the dissociation observed in chronic PTSD. This is why we called attention to the ICD-10 nosology, which distinguishes between these kinds of symptoms by recognizing an acute stress reaction as well as a posttraumatic stress syndrome.

2. After acknowledging the limitations of predictor analyses for syndrome identification in their first point, Dr. Spiegel and colleagues then cite predictor analyses as a major justification for acute stress disorder. Our article never argued that dissociative symptoms should be dropped from the diagnosis of acute stress disorder because of their limitations as predictors. Rather, we called attention to the subgroup of individuals who do not experience dissociative symptoms. The point that using the same symptom assessment methodology would increase predictive power is certainly true but has no bearing on any of our lines of reasoning, as noted previously.

3. Even a casual reader of our article would have probably taken note of our several discussions of the issue of stigmatization, which was designated specifically as one of three major points of contention in trauma research (p. 1678). We also refer the reader to our discussions on pp. 1679, 1682, and 1683 because this is too important and complex an issue to recapitulate in a limited amount of space.

4. The statement that we "highlight" the retrospective studies is simply wrong (a point also made in other letters). Prospective studies were the primary basis for our conclusions, and in any case, the prospective and retrospective studies were largely consistent with respect to our several major points.

These letters give the impression of some kind of power struggle over the importance of dissociation. After months of consideration and discussion with others in the field, we believe our recommendation was actually a more balanced, nosologically valid, empirically based perspective. The fact that one trauma diagnosis (acute stress disorder) requires dissociative symptoms, whereas the second (PTSD) does not even recognize them, may be symptomatic of this unfortunate polarization within the field. We appreciate the positive feedback we have received on this central point from clinicians and investigators working with trauma patients.