Psychological mechanisms in acute response to trauma.

Traumatic events are common, but posttraumatic stress disorder (PTSD) is relatively rare. These facts have prompted several questions: What variables increase risk for PTSD among trauma-exposed people? Can we distinguish between pathologic and nonpathologic responses to traumatic stressors? If so, what psychobiological mechanisms mediate pathologic responses? Prospective studies have identified certain individual difference variables as heightening risk (e.g., lower intelligence, negative personality traits). Studies on peritraumatic and acute-phase response have identified certain dissociative symptoms (e.g., time slowing, derealization) and cognitive appraisal (e.g., belief that one is about to die) as harbingers of later PTSD. Negative appraisal of acute symptoms themselves may foster chronic morbidity (e.g., that symptoms signify shameful moral weakness or prefigure impending psychosis). Further attempts to elucidate pathologic mechanisms in the cognitive psychology laboratory and via biological challenges are warranted.