Posttraumatic stress disorder (PTSD) is a mental disorder that can develop after a person is exposed to a traumatic event, such as sexual assault, warfare, traffic collisions, or other threats on a person's life. Symptoms may include disturbing thoughts, feelings, or dreams related to the events, mental or physical distress to trauma-related cues, attempts to avoid trauma-related cues, alterations in how a person thinks and feels, and an increase in the fight-or-flight response. These symptoms last for more than a month after the event. Young children are less likely to show distress, but instead may express their memories through play. A person with PTSD is at a higher risk for suicide and intentional self-harm.Most people who have experienced a traumatic event will not develop PTSD. People who experience interpersonal trauma (for example rape or child abuse) are more likely to develop PTSD, as compared to people who experience non-assault based trauma, such as accidents and natural disasters. About half of people develop PTSD following rape. Children are less likely than adults to develop PTSD after trauma, especially if they are under 10 years of age. Diagnosis is based on the presence of specific symptoms following a traumatic event.Prevention may be possible when counselling is targeted at those with early symptoms but is not effective when provided to all trauma-exposed individuals whether or not symptoms are present. The main treatments for people with PTSD are counselling (psychotherapy) and medication. Antidepressants of the selective serotonin reuptake inhibitor type are the first-line medications for PTSD and result in benefit in about half of people. These benefits are less than those seen with counselling. It is unclear if using medications and counselling together has greater benefit. Other medications do not have enough evidence to support their use, and in the case of benzodiazepines, may worsen outcomes.In the United States about 3.5% of adults have PTSD in a given year, and 9% of people develop it at some point in their life. In much of the rest of the world, rates during a given year are between 0.5% and 1%. Higher rates may occur in regions of armed conflict. It is more common in women than men. Symptoms of trauma-related mental disorders have been documented since at least the time of the ancient Greeks. During the World Wars the condition was known under various terms including "shell shock" and "combat neurosis". The term "posttraumatic stress disorder" came into use in the 1970s in large part due to the diagnoses of U.S. military veterans of the Vietnam War. It was officially recognized by the American Psychiatric Association in 1980 in the third edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III).