Post-traumatic stress disorder, often abbreviated as PTSD, is a complex disorder in which the affected person’s memory, emotional responses, intellectual processes, and nervous system have all been disrupted by one or more traumatic experiences. It is sometimes summarized as “a normal reaction to abnormal events.”

PTSD has a unique position as the only psychiatric diagnosis(along with acute stress disorder) that depends on a factor outside the individual, namely, a traumatic stressor. A patient cannot be given a diagnosis of PTSD unless he or she has been exposed to an event that is considered traumatic. These events include such obvious traumas as rape, military combat, torture, genocide, natural disasters, and transportation or workplace disasters. In addition, it is now recognized that repeated traumas or such traumas of long duration as child abuse, domestic violence, stalking, cult membership, and hostage situations may also produce the symptoms of PTSD in survivors.

A person suffering from PTSD experiences flashbacks, nightmares, or daydreams in which the traumatic event is experienced again. The person may also experience abnormally intense startle responses, insomnia, and may have difficulty concentrating. Trauma survivors with PTSD have been effectively treated with group therapy or individual psychological therapy, and other therapies have helped individuals, as well. Some affected individuals have found support groups or peer counseling groups helpful.