Posttraumatic stress disorder (PTSD) may develop after a person is exposed to one or more traumatic events, such as sexual assault, warfare, serious injury, or threats of imminent death that result in feelings of intense fear, horror, and powerlessness. The diagnosis may be given when a group of symptoms, such as disturbing recurring flashbacks, avoidance or numbing of memories of the event, and hyperarousal, continue for more than a month after the occurrence of traumatic event.