PTSD (post traumatic stress disorder) is a mental health disease that found some those peoples who develop after experiencing or witnessing a life-dangerous event, like combat, a car accident, a natural disaster, helplessness, or horror such as sexual assault , counting difficulty sleeping ,flashback, and anxiety.
It is common to feel fear during and after a traumatic situation. However the people who have sick by PTSD and they always feel stressed or frightened, even when they are not at risk.
In the past, PTSD is also known as many others names like shell shock and combat fatigue before the years of World War II. PTSD affects specially women as compare to men and approximately 4.5 percent of U.S. Youngers. It happen as a reaction to chemical and neuronal changes in the brain after exposure to threatening events.
Those people who experience a traumatic have symptoms found for longer duration (than one month) and change function as well as before the event occurred.