Post-traumatic stress disorder, or PTSD, is a psychological condition associated with prior exposure to serious traumatic events. Post-traumatic stress disorder is an anxiety disorder in which symptoms are triggered by traumatic events. Survivors of PTSD experience with an intense fear during which they feel deeply threatened, and tend to experience flashbacks of their traumatic experiences. It is not known why PTSD occurs, but it appears that social, psychological, genetic, and physical factors contribute to PTSD. People with PTSD become emotionally detached and numb, and may behave irritably or act out in anger. Support groups, therapy, and sometimes medications can help people with PTSD manage their symptoms and overcome past trauma.