The epidemiology of post-traumatic stress disorder after disasters.

Traumatic experiences are relatively common. More than two thirds of persons in the general population may experience a significant traumatic event at some point in their lives, and up to one fifth of people in the United States may experience such an event in any given year (1–5). Although comparable international data are limited, large proportions of populations in many countries have been exposed to terrorism, forced relocation, and violence, which suggests that the overall prevalence of exposure to traumatic events worldwide may be even higher than that in the United States (6, 7). Disasters (e.g., floods, transportation accidents) are traumatic events that are experienced by many people and may result in a wide range of mental and physical health consequences (8). In one survey of US residents, 13 percent of the sample reported a lifetime exposure to natural or human-generated disaster (9). In the National Comorbidity Survey, 18.9 percent of men and 15.2 percent of women reported a lifetime experience of a natural disaster (4). Posttraumatic stress disorder (PTSD) is the most commonly studied and probably the most frequent and debilitating psychological disorder that occurs after traumatic events and disasters (8, 10). The growing threat of terrorism worldwide has heightened our awareness of disasters as a potentially important determinant of population health and suggests a pressing need both to identify key areas of consensus in postdisaster research and to highlight areas that require additional study (11). It is our purpose in this review to contribute to this overall goal by comprehensively and systematically assessing the epidemiologic evidence about PTSD after disasters. REVIEW OF THE LITERATURE