Narrator: This is Science Today. In the months following last year's terrorist attacks, there's been much discussion about post-traumatic stress disorder, or PTSD, and what to do about it. Dr. Frank Schoenfeld, director of the University of California, San Francisco's Post Traumatic Stress Disorder Center, describes symptom clusters of PTSD.
Schoenfeld: The first and most characteristic for PTSD is re-experiencing - people will have nightmares about the traumatic experience, but during the daytime, they may also have vivid, intrusive memories that are unwanted and they can't get out of their minds. Also, there's avoidance and numbing.
Narrator: Schoenfeld says identifying people at risk early on becomes critical.
Schoenfeld: People who are less socially advantaged are at risk. There's often less social support and less structures to mobilize to help once they get into difficulties. In a time relationship, if somebody's been under stress in the year prior to a traumatic event, that puts them at higher risk.
Narrator: For Science Today, I'm Larissa Branin.