The relationship between acute stress disorder and posttraumatic stress disorder: a prospective evaluation of motor vehicle accident survivors.

Motor vehicle accident survivors (n = 92) were assessed for acute stress disorder (ASD) within 1 month of the trauma and reassessed (n = 71) for posttraumatic stress disorder (PTSD) 6 months posttrauma. ASD was diagnosed in 13% of participants, and a further 21% had subclinical levels of ASD. At follow-up, 78% of ASD participants and 60% of subclinical ASD participants met criteria for PTSD. The strong predictive power of acute numbing, depersonalization, a sense of relieving the trauma, and motor restlessness, in contrast to the low to moderate predictive power of other symptoms, indicates that only a subset of ASD symptoms is strongly related to the development of chronic PTSD. Although these findings support the use of the ASD diagnosis, they suggest that the dissociative and arousal clusters may require revision.