Some people are at greater risk for PTSD than others. People most at risk have experienced the most intense exposure to the event.

In the case of a terror attack, a military threat or a frightening storm, those who are closest to the event, are threatened with severe injury or become injured, or who have a close relationship with someone who was killed or injured are more likely than others to be diagnosed with PTSD. Some people who watched extensive media coverage on September 11, 2001 may develop anxiety symptoms similar to PTSD, but unless they were personally threatened, people in that situation probably have a different kind of anxiety disorder.

The risk of psychological distress after a traumatic event increases with the following characteristics:

• female gender
• age 40 to 60 years
• little previous experience or training relevant to coping with disaster
• low socioeconomic status
• children present in the home
• being a married woman, especially if your husband is significantly distressed
• a past history of psychiatric distress
• close exposure to the disaster (injury, threat to life, loss of home)
• living in a highly disrupted or traumatized community.

Violence that is man-made, whether by an individual or group, has a greater psychologically harmful effect than does an accident or natural disaster. After living through a natural disaster, about 1 in 20 people will develop PTSD, while as many as 7 in 20 will develop PTSD if they are victims of man-made violence. Still—no matter what the cause—exposure to death, mortal danger or mass destruction, or the loss of a loved one or a home are key risk factors for this illness.

Although many reactions to a stressful event are disturbing, they are considered normal expressions of emotion in the aftermath. In fact, it would be unusual to have no reaction at all.

In some instance, these experiences contribute to our coping, for example, by mobilizing family and friends to provide support. Other normal reactions include fatigue, insomnia, confusion, difficulty feeling happy, irritability, emotional numbness, and feelings of vulnerability, self-blame, alienation, and distrust.

Symptoms may appear immediately, but they must last for at least one month to be considered symptoms of PTSD. Health professionals use several criteria to diagnose PTSD. An individual must have been exposed to a horrifying traumatic event that involved actual or threatened death or serious injury. (For the purpose of making this diagnosis, stressful life events such as bankruptcy or divorce are not considered traumatic, because they do not threaten a person's physical integrity.) He or she must have felt intense fear or helplessness during the experience.

The symptoms are many and varied. A person with PTSD re-experiences the trauma through recollections, dreams, or responses to cues or reminders of the event. He or she tends to avoid thoughts, feelings, places or people that are associated with the trauma. He or she may withdraw from activities, feel detached or numb, or feel that the future has been curtailed. A PTSD sufferer also is more "aroused," for example, having trouble sleeping, being more irritable, having trouble concentrating, being hypervigilant or easily startled.

There are good ways to cope without contacting a professional. You can decrease your risk of serious long-term effects by learning about PTSD. That will help you understand how trauma affects people and how common the symptoms are. You can talk with friends or family about your experiences when you are ready to do so. One popular belief is that people should be pushed to talk, but that's not true. Some people never choose to talk about the experience, and that is sometimes best.

Talking to other trauma survivors can help, but in some cases it can amplify anxiety rather than calm it. An important aim of talking, in addition to validating your reactions, is to get help with day-to-day functioning and moving on with life.

It helps some people to practice methods of relaxation, including yoga, deep breathing, meditation, stretching, prayer, swimming, long walks, or any form of exercise that calms you. Distractions also help: Examples are creative hobbies like arts, crafts or playing an instrument, or becoming active in a volunteer activity, especially one that brings you in contact with other people in your community.

Although you can do plenty of things for yourself, it's a good idea to talk to a counselor or other health professional if you are having trouble functioning or are feeling distress that you can't manage on your own.

Research—including research on the effects of the Oklahoma City bombing—has shown that many people closest to a traumatic event do not seek help, even though they have considerable emotional distress. People may feel that because they survived the event, they "shouldn't" feel so upset. Others may feel that seeking help from a mental-health professional is a sign of weakness.

It is not a sign of weakness to ask for help. It may actually be a sign of strength to do so! Even people who can talk to family and friends about their experiences may also need to talk to a professional therapist or counselor. Medication is often very helpful too.

It's a fairly common problem that a person wants to talk to a mental health professional, but is reluctant to reach out. There should be no shame in talking, and it can be a relief to find out that stress reactions are very human. Contact a counselor or mental health professional if your distress is hard to manage.

Communication with your children can help them put the event in perspective and reassure them.

It is important, however, for adults to get a handle on their own anxiety before talking to children, because children have very good antennae for other people's feelings. If the adult is calm, that can have a very calming effect on the child. This also makes it easier for the child to ask questions and discuss the events.

Follow the child's lead and provide information that is accurate but also age-appropriate. A small child has a very limited concept of the world at large, of health and illness or of life and death. Ask them how they feel. Provide realistic reassurance about how people are being helped and what is being done to prevent future violence.