May 2 (HealthDay News) -- Social workers run the risk of suffering severe psychological stress from hearing too many stories of trauma, according to a new study that looked at people who counseled others impacted by the Sept. 11 terror attacks in New York City.

A positive work environment, the study also found, can help reduce secondary trauma and prevent job burnout from this secondary, or vicarious, trauma.

"Listening to a person's traumatic experiences can be a difficult experience for a clinician," senior investigator Joseph Boscarino, of Geisinger Health System, said in a prepared statement. "Sometimes caregivers need emotional support of their own, and if they don't get it, they can become emotionally ill."

His team's findings, expected to be published in the May issue of Research on Social Work Practice, are based on a study of the lives of 236 New York City social workers following the Sept. 11, 2001, terror attacks.

The symptoms of secondary trauma are similar to those of post-traumatic stress disorder. They include nightmares or flashbacks, being easily startled, and avoiding situations similar to the original trauma.

The study found that involvement in the World Trade Center recovery effort was the primary reason why social workers experienced secondary trauma.

SOURCE: Geisinger Health System, news release, April 21, 2008