Posttraumatic stress disorder (PTSD) is a delayed onset and long-term persistent psychiatric disorder resulting from an unusually threatening, catastrophic psychological trauma. PTSD was originally used to describe the range of consequences for veterans, prisoners of war, and concentration camp survivors after a traumatic war event, and then gradually was used to describe the range of stress symptoms that occur in victims of various man-made and natural disasters. Such events include serious accidents, earthquakes, rape, kidnapping, and witnessing the tragic death of others. Almost all people who experience such events feel great distress, often causing feelings of extreme fear, stress, and helplessness.