Post-traumatic stress disorder (PTSD) is a mental health disorder that some people develop after they experience or see a traumatic event. The traumatic event may be life-threatening, such as combat, a natural disaster, a car accident, or sexual assault. But sometimes the event is not necessarily a dangerous one. For example, the sudden, unexpected death of a loved one can also cause PTSD.

It's normal to feel afraid during and after a traumatic situation. The fear triggers a "fight-or-flight" response. This is your body's way of helping to protect itself from possible harm. It causes changes in your body such as the release of certain hormones and increases in alertness, blood pressure, heart rate, and breathing.

In time, most people recover from this naturally. But people with PTSD don't feel better. They feel stressed and frightened long after the trauma is over. In some cases, the PTSD symptoms may start later on. They might also come and go over time.

Researchers don't know why some people get PTSD and others don't. Genetics, neurobiology, risk factors, and personal factors may affect whether you get PTSD after a traumatic event.

You can develop PTSD at any age. Many risk factors play a part in whether you will develop PTSD. They include:

• Your sex; women are more likely to develop PTSD
• Having had trauma in childhood
• Feeling horror, helplessness, or extreme fear
• Going through a traumatic event that lasts a long time
• Having little or no social support after the event
• Dealing with extra stress after the event, such as loss of a loved one, pain and injury, or loss of a job or home
• Having a history of mental illness or substance use

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

• Re-experiencing symptoms, when something reminds you of the trauma and you feel that fear again. Examples include
  • Flashbacks, which cause you to feel like you are going through the event again
  • Nightmares
  • Frightening thoughts
• Avoidance symptoms, when you try to avoid situations or people that trigger memories of the traumatic event. This may cause you to
  • Stay away from places, events, or objects that are reminders of the traumatic experience. For example, if you were in a car accident, you might stop driving.
  • Avoiding thoughts or feelings related to the traumatic event. For example, you might try to stay very busy to try to avoid thinking about what happened.
• Arousal and reactivity symptoms, which may cause you to be jittery or be on the lookout for danger. They include
  • Being easily startled
  • Feeling tense or "on edge"
  • Having difficulty sleeping
  • Having angry outbursts
• Cognition and mood symptoms, which are negative changes in beliefs and feelings. They include
  • Trouble remembering important things about the traumatic event
  • Negative thoughts about yourself or the world
  • Feeling blame and guilt
  • No longer being interested in things you enjoyed
  • Trouble concentrating

The symptoms usually start soon after the traumatic event. But sometimes they may not appear until months or years later. They also may come and go over many years.

If your symptoms last longer than four weeks, cause you great distress, or interfere with your work or home life, you might have PTSD.

A health care provider who has experience helping people with mental illnesses can diagnose PTSD. The provider will do a mental health screening and may also do a physical exam. To get a diagnosis of PTSD, you must have all of these symptoms for at least one month:

• At least one re-experiencing symptom
• At least one avoidance symptom
• At least two arousal and reactivity symptoms
• At least two cognition and mood symptoms

The main treatments for PTSD are talk therapy, medicines, or both. PTSD affects people differently, so a treatment that works for one person may not work for another. If you have PTSD, you need to work with a mental health professional to find the best treatment for your symptoms.:

• Talk therapy, or psychotherapy, can teach you about your symptoms. You will learn how to identify what triggers them and how to manage them. There are different types of talk therapy for PTSD.
• Medicines can help with the symptoms of PTSD. Antidepressants may help control symptoms such as sadness, worry, anger, and feeling numb inside. Other medicines can help with sleep problems and nightmares.

There are certain factors that can help reduce the risk of developing PTSD. These are known as resilience factors, and they include:

• Seeking out support from other people, such as friends, family, or a support group
• Learning to feel good about your actions in the face of danger
• Having a coping strategy or a way of getting through the bad event and learning from it
• Being able to act and respond effectively despite feeling fear

NIH: National Institute of Mental Health