PTSD occurs when you have been involved in a situation where there was the reality or the perception of the possibility of death or injury to yourself or someone close to you.

In this situation you may have felt powerless, helpless, a great sense of fear, danger or horror. 

These include events like:

Car Accidents

Physical injuries from falls

Childhood surgeries

Physical abuse

Sexual abuse

War

Natural Catastrophies

In general, symptoms associated with PTSD include:

Repetitive distressing thoughts about the event: that means you keep thinking about what happened, the thoughts come into your mind at different times. Sometimes it seems you just can't get them out of your mind and you feel you can't get over the event.
This may interfere with your ability to concentrate and be focused.

Dreams or nightmares about the event: some people still have nightmares about the war, accidents and childhood abuse many years after the event.

You may feel out of touch with your feelings, even numb, shut down, or feel like you’re "dead inside".

Difficulty with sleep

Hypervigilance: always being on guard, fearing that someone might hurt you or something bad will happen any moment.

Exaggerated startled response: jumping or over reacting to noises or someone surprising you.