Posttraumatic Stress Disorder (PTSD) is an anxiety disorder that can occur after you have been through a traumatic event. Strong emotions caused by the event create changes in the brain that may result in PTSD.

When we're in danger, it’s natural to feel afraid. This fear triggers many split-second changes in the body to prepare to defend against the danger or to avoid it.

This “fight-or-flight” response is a healthy reaction meant to protect a person from harm. But in PTSD, this reaction is changed or damaged. People who have PTSD may feel stressed or frightened even when they’re no longer in danger.

People who have gone through a life-threatening event can develop PTSD. These events can include:

• Combat or military exposure
• Child sexual or physical abuse
• Terrorist attacks
• Sexual or physical assault
• Serious accidents, such as a car wreck.
• Natural disasters, such as a fire, tornado, hurricane, flood, or earthquake.

After the event, you may feel scared, confused, or angry. If these feelings don't go away or they get worse, you may have PTSD. These symptoms may disrupt your life, making it hard to continue with your daily activities.

Most people who go through a traumatic event have some symptoms at the beginning. Yet only some will develop PTSD. It isn't clear why some people develop PTSD and others don't. How likely you are to get PTSD depends on many things. These include:

• How intense the trauma was or how long it lasted
• If you lost someone you were close to or were hurt
• How close you were to the event
• How strong your reaction was
• How much you felt in control of events
• How much help and support you got after the event

Many people who develop PTSD get better at some time. But about 33% of people with PTSD may continue to have some symptoms. Even if symptoms continue, treatment can help. The symptoms don't have to interfere with everyday activities, work, and relationships.

What are the symptoms of PTSD?

Symptoms of posttraumatic stress disorder (PTSD) can be terrifying. They may disrupt life and make it hard to continue with daily activities. It may be hard just to get through the day.

PTSD symptoms usually start soon after the traumatic event, but they may not happen 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 may have PTSD.

There are four types of PTSD symptoms: reliving the event, avoidance, numbing, and hyperarousal.

1. Reliving the event (also called re-experiencing symptoms): Bad memories of the traumatic event can come back at any time. You may feel the same fear and horror you did when the event took place. You may have nightmares. You even may feel like you're going through the event again. This is called a flashback. Sometimes there is a trigger: a sound or sight that causes you to relive the event. Triggers might include:
   • Hearing a car backfire, which can bring back memories of gunfire and war for a combat veteran (flashback).
   • Seeing a car accident, which can remind a crash survivor of his or her own accident.
   • Seeing a news report of a sexual assault, which may bring back memories of assault for a woman who was raped.
2. Avoidance of situations that remind people of the event: They may try to avoid situations or people that trigger memories of the traumatic event. They may even avoid talking or thinking about the event. Examples:
   • A person who was in an earthquake may avoid watching television shows or movies in which there are earthquakes.
   • A person who was robbed at gunpoint while ordering at a hamburger drive-in may avoid fast-food restaurants.
   • Some people may keep very busy or avoid seeking help. This keeps them from having to think or talk about the event.
3. Numbing: People with PTSD may find it hard to express their feelings. This is another way to avoid memories...
   • They may not have positive or loving feelings toward other people and may stay away from relationships.
   • They may not be interested in activities you used to enjoy.
   • They may forget about parts of the traumatic event or not be able to talk about them.
4. Hyperarousal (feeling keyed up): Those with PTSD may be jittery, or always alert and on the lookout for danger. Hyperarousal symptoms are usually constant, instead of being triggered by things that remind one of the traumatic event. They can make the person feel stressed and angry. Hyperarousal can cause people to:
   • Suddenly become angry or irritable.
   • Have a hard time sleeping.
   • Have trouble concentrating.
   • Fear for their safety and always feel on guard.
   • Be very startled when someone surprises them.

People with PTSD may also have other issues including: