Post Traumatic Stress Disorder (PTSD) is an extreme form of anxiety following a traumatic event. Sufferers often develop PTSD after experiencing an event that caused them to feel extreme fear, shock or helplessness such as a car accident or wartime atrocity or after being repeatedly exposed to trauma such as childhood abuse or sexual violence.
There is no one single reason why someone will develop PTSD after experiencing trauma and someone else will not. Genetic and environmental factors are both believed to play a part in the predisposition for developing PTSD.
Someone who has previously experienced a traumatic event is thought to have a higher chance of developing PTSD, as is someone who has been exposed to trauma over a period of time (such as childhood abuse or living in a war zone).
Someone with a history of other types of mental illness is also believed to be more susceptible to PTSD, along with anyone experiencing ongoing stressful life events following a trauma without the benefit of any social supports.
Whether the traumatic event was intentional or not may also have a bearing, with someone experiencing a natural disaster thought less likely to develop PTSD than someone who has been sexually assaulted or suffers some other form of intentional physical violence.