Post-traumatic stress disorder, or PTSD, is a new name for a very old condition. In the earlier 1900s, it was known as "shell shock" or "battle fatigue." Before then, it had no name. In PTSD, a witness or victim of a terrible event or tragedy is so haunted by memories of the event that personal health and personality is affected. Events likely to lead to PTSD are those that cause the victim to feel fear, horror, or helplessness. Many people start to have symptoms within three months of the trauma, but symptoms may occur later. PTSD often occurs together with other conditions such as depression, anxiety, or substance abuse.
Research suggests that approximately 9% of the Canadian population will be affected at one time in their life with PTSD. Women are twice as likely to be affected as men. The specific type of trauma is important in the gender distribution. For example, women exposed to a physical attack or threatened with a weapon are more likely to develop PTSD than men who are exposed to the same trauma. But women who are sexually assaulted are less likely to develop PTSD than men who are sexually assaulted.