284 Trauma- and Stressor-Related Disorders
caregivers. In the case of be reavement following a death that occurred in traumatic cir-
cumstances, the symptoms of acute stress di sorder can involve acute grief reactions. In
such cases, reexperiencing, dissociative, an d arousal symptoms ma y involve reactions to
the loss, such as intrusive memories of the ci rcumstances of the individual’s death, disbe-
lief that the individual has died, and ange r about the death. Po stconcussive symptoms
(e.g., headaches, dizziness, sensitivity to light or sound, irritability, concentration deficits),
which occur frequently following  mild traumatic brain injury, are also frequently seen in
individuals with acute stress disorder. Po stconcussive symptoms are equally common in
brain-injured and non–brain-injured populations, and the frequent occurrence of postcon-
cussive symptoms could be attributable  to acute stress disorder symptoms. 
Prevalence
The prevalence of acute stress disorder in recently trauma-exposed populations (i.e.,
within 1 month of trauma exposure) varies ac cording to the nature of the event and the
context in which it is assessed. In both U.S. and non-U.S. population s, acute stress disorder
tends to be identified in less than 20% of ca ses following traumatic events that do not in-
volve interpersonal assault; 13%–21% of motor vehicle accidents, 14% of mild traumatic
brain injury, 19% of assault, 10% of severe burns, and 6%–12% of industrial accidents.
Higher rates (i.e., 20%–50%) are reported following interpersonal traumatic events, in-
cluding assault, rape, and witnessing a mass shooting. 
Development and Course