The contribution of epidemiology to the study of traumatic stress.

Post-traumatic stress disorder (PTSD) has been a controversial construct because of the complex set of factors that have been hypothesized to influence its onset and prevalence, such as compensation and withdrawal from combat duty. Epidemiology has done much to objectively clarify these controversies in the study of stratified population samples. The symptoms characterizing PTSD have been repeatedly described in large population samples where compensation is not a confounding issue and this has done much to support the validity of the construct. Epidemiology has also highlighted that the prevalence of exposure to traumatic events is far greater than was previously estimated. Emphasizing the importance of these events is accounting for the major burden of disease. Kessler (2000) has suggested the socio-economic effects of PTSD represent a burden of disease not dissimilar to that associated with depression. Traumatic events provide a unique opportunity to implement a preventative and public health approach to the management of psychiatric morbidity. Of particular importance is the apparent longevity of the influence that these events have on psychological adjustment.