Posttraumatic stress disorder
A disorder that may result when an individual lives through or witnesses an event in which they believe that there is a threat to life or physical integrity and safety and experiences fear, terror, or helplessness.
The symptoms are characterized by (a) reexperiencing the trauma in painful recollections, flashbacks, or recurrent dreams or nightmares; (b) avoidance of activities or places that recall the traumatic event, as well as diminished responsiveness (emotional anesthesia or numbing), with disinterest in significant activities and with feelings of detachment and estrangement from others; and (c) chronic physiological arousal, leading to such symptoms as an exaggerated startle response, disturbed sleep, difficulty in concentrating or remembering, and guilt about surviving the trauma when others did not.
Adapted from the APA Dictionary of Psychology

