PTSD can happen to anyone. It is not a sign of weakness. A number of factors can increase the chance that someone will have PTSD, many of which are not under that person’s control. For example, having a very intense or long-lasting traumatic event or getting injured during the event can make it more likely that a person will develop PTSD. PTSD is also more common after certain types of trauma, like combat and sexual assault.

Personal factors, like previous traumatic exposure, age, and gender, can affect whether or not a person will develop PTSD. What happens after the traumatic event is also important. Stress can make PTSD more likely, while social support can make it less likely.
What are the symptoms of PTSD?

PTSD symptoms usually start soon after the traumatic event, but they may not appear until months or years later. They also may come and go over many years. If the symptoms last longer than four weeks, cause you great distress, or interfere with your work or home life, you might have PTSD.

There are four types of symptoms of PTSD, but they may not be exactly the same for everyone. Each person experiences symptoms in their own way.

• Reliving the event (also called re-experiencing symptoms). You may have bad memories or nightmares. You even may feel like you’re going through the event again. This is called a flashback.
• Avoiding situations that remind you of the event. You may try to avoid situations or people that trigger memories of the traumatic event. You may even avoid talking or thinking about the event.
• Having more negative beliefs and feelings. The way you think about yourself and others may change because of the trauma. You may feel guilt or shame. Or, you may not be interested in activities you used to enjoy. You may feel that the world is dangerous and you can’t trust anyone. You might be numb, or find it hard to feel happy.
• Feeling keyed up (also called hyperarousal). You may be jittery, or always alert and on the lookout for danger. Or, you may have trouble concentrating or sleeping. You might suddenly get angry or irritable, startle easily, or act in unhealthy ways (like smoking, using drugs and alcohol, or driving recklessly.
  Definition of PTSD by https://www.ptsd.va.gov/public/PTSD-overview/basics/what-is-ptsd.asp