Risk and Resilience in Posttraumatic Stress Disorder

Posttraumatic stress disorder (PTSD) is a fairly common psychiatric disorder that is associatedwith a lifetime prevalence of approximately 9% in the United States. In light of recent war and terroristactivity worldwide, it is likely that increased numbers of individuals will be exposed to severe orlife-threatening trauma, and the incidence of PTSD may be even higher than previously indicated inepidemiologic studies. PTSD may develop after exposure to a traumatic event in which the individualexperienced, witnessed, or was confronted by either actual or threatened loss of life or serious injury.Patients with PTSD often reexperience intrusive recollections of the event in ways that are highly distressingand may be described as reliving the memory. Not surprisingly, symptoms of avoidance arenoted because individuals with PTSD often wish to escape recollections (thoughts, feelings, conversations,places) related to the trauma. Patients also experience symptoms of hyperarousal associatedwith difficulty concentrating or exaggerated startle response. Notably, individuals who develop PTSDrepresent only a subset of those exposed to trauma. It is of interest why certain individuals are at riskfor development of PTSD after traumatic exposure, whereas others appear to be more resilient to theeffects of trauma. Studies suggest that previous exposure to trauma and intensity of the response toacute trauma may affect the development of PTSD. In addition, however, neuroendocrine changes,such as lower cortisol levels, also may influence formation and processing of traumatic memories andmay be associated with the underlying pathology of PTSD.