Posttraumatic stress disorder ; on-line (PTSD) is an anxiety disorder that can develop after exposure to one or more traumatic events that threatened or caused grave physical harm. PTSD affects over 7.8 million people.Fact: date=April 2009

It is a severe and ongoing emotional reaction to an extreme psychological trauma. This stressor may involve someone's actual death, a threat to the patient's or someone else's life, serious physical injury, an unwanted sexual act, or a threat to physical or psychological integrity, overwhelming psychological defenses.

In some cases it can also be from profound psychological and emotional trauma, apart from any actual physical harm. Often, however, incidents involving both things are found to be the cause.

PTSD is a condition distinct from traumatic stress, which has less intensity and duration, and combat stress reaction, which is transitory. PTSD has also been recognized in the past as railway spine, stress syndrome, shell shock, battle fatigue, traumatic war neurosis, or post-traumatic stress syndrome (PTSS).

Diagnostic symptoms include reexperience such as flashbacks and nightmares, avoidance of stimuli associated with the trauma, increased arousal such as difficulty falling or staying asleep, anger and hypervigilance. Per definition, the symptoms last more than six months and cause significant impairment in social, occupational, or other important areas of functioning (e.g. problems with work and relationships.)

Causes

main: Psychological trauma

PTSD is believed to be caused by psychological trauma. Possible sources of trauma include encountering or witnessing childhood or adult physical, emotional or sexual abuse. In addition, encountering or witnessing an event perceived as life-threatening such as physical assault, adult experiences of sexual assault, accidents, drug addiction, illnesses, medical complications, or employment in occupations exposed to war (such as soldiers) or disaster (such as emergency service workers).

Traumatic events that may cause PTSD symptoms to develop include violent assault, kidnapping, sexual assault, torture, being a hostage, prisoner of war or concentration camp victim, experiencing a disaster, violent automobile accidents or getting a diagnosis of a life-threatening illness. Children may develop PTSD symptoms by experiencing sexually traumatic events like age-inappropriate sexual experiences.

Witnessing traumatic experiences or learning about these experiences may also cause the development of PTSD symptoms. The amount of dissociation that follows directly after a trauma predicts PTSD: individuals who are more likely to dissociate during a traumatic event are considerably more likely to develop chronic PTSD.