If you think of the thousands of people who witnessed the terrors and catastrophes at the World Trade Center that morning of Sept. 11, you have to marvel that now, just a few years later, only about one in 10 still struggles with severe anxiety over that event.

And that's true for tsunami survivors - and survivors of most disasters. About 10 percent will develop post-traumatic stress disorder.

So why some people and not others?

There's so much we don't know, but we do know this: Children and young adults are generally more vulnerable than older adults. And people who have had previous traumas or mental illness are more likely to develop PTSD.

Severe physical injury also raises the risk for PTSD, as does having nobody to talk to about the traumatic event.

So far there's no good biological test for PTSD. But the best predictor of whether a disaster survivor will develop PTSD comes from close observation of how he or she reacts during the first month after the trauma.

If the key signs of PTSD develop and persist in the first month - flashbacks, nightmares, startle responses and blanking out memories - the chances are high that PTSD could become a chronic problem.

The good news is that recent studies have shown that early treatment of these symptoms with cognitive therapy reduces the risk of later PTSD by half. Early treatment with medications may also help but has not been studied as well.

Source: Enquirer