ABSTRACT
Previous research has identified acute stress symptoms, particularly peri-traumatic dissociative symptoms (the distortion of consciousness, depersonalization, derealization, automatic movements, flashbacks with illusions or hallucinations), as risk factors for the development of later posttraumatic stress disorder. Numerous retrospective assessments and current prospective studies confirm these findings. It is suggested that peri-traumatic dissociation be assessed immediately after traumatic exposure and during the weeks following. But traumatized victims may present other categories of acute reactions; panic attacks, acute depression, conversion reaction, excessive emotional expression, and psychotic reactions. Brief reactive psychosis is a major differential diagnosis with peri-traumatic dissociative experiences. During emergency interventions it may be difficult to distinguish between dissociative and psychotic symptoms. It is cautioned that these disorders be evaluated with a follow-up of several months.