Post-traumatic stress disorder or PTSD is an anxiety disorder brought on by some traumatic, frightening or life threatening event. People with this disorder tend to relive the experience in some way and try to avoid people, places or things that they associate with that event (avoidance). It has only been formally classified as an anxiety disorder since 1980, but has been referred to by different names since as early as the American civil war, when it was known as "soldier's heart". It has also been referred to as "battle fatigue" and "shell shock".
Complex post-traumatic stress disorder (C-PTSD) results from prolonged exposure to a traumatic event or a series of such events. It is characterized by long lasting emotional and behavioral problems that affect a person's ability to function in society.
Statistical studies indicate that approximately 7 to 8% of people in the United States will develop PTSD during their lifetime. That figure may range from10% to 30% in victims of violent crimes like rape and in the case of combat veterans.