Military works to predict PTSD risk

TWENTYNINE PALMS, Calif. -- A military experiment is under way to try to predict who's most at risk for post-traumatic stress disorder.

Doctors say understanding underlying triggers might help reduce the burden of those who return from combat psychologically wounded, if they can get early help.

PTSD is a crippling condition that can emerge after a terrifying event -- car accident, sexual assault, terrorist attack or combat.

It's thought to affect as many as one in five veterans returning from Afghanistan and Iraq.

The mystery is why certain troops develop paralyzing stress symptoms while others shake it off.

There are no reliable predictors, but childhood abuse, history of mental illness and severity of trauma seem to raise a person's risk. Having a social net and a coping strategy appear to offer some protection.

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