Sept. 6 (HealthDay News) -- Adults whose mother or father suffered from post-traumatic stress disorder (PTSD) often experience the biological signs of PTSD themselves, such as below-average levels of the stress hormone cortisol, researchers report.

The research involved the adult offspring of Holocaust survivors with PTSD.

A team of researchers from the Mount Sinai School of Medicine and the James J. Peters Veterans Affairs Medical Center, New York City, studied 33 people whose parents had survived the Holocaust.

The study participants were subdivided into groups based on whether at least one parent met the criteria for PTSD. Twenty-three of the participants had at least one parent with PTSD, and 10 had parents without PTSD.

The researchers measured blood cortisol levels every 30 minutes for a 24-hour period and then compared those levels with those of people whose parents were not Holocaust survivors. None of the participants had PTSD at the time of the study.

People who had at least one parent with PTSD had lower than average levels of cortisol over the test period compared to those whose parents did not have PTSD or had not been in the Holocaust. According to the researchers, the effect was strongest among people whose mother had PTSD.

Writing in the September issue of the Archives of General Psychiatry, the authors said the research might lead to better prevention and treatment of PTSD, including addressing PTSD and stressful events experienced by parents during pregnancy and childhood.

SOURCE: JAMA/Archives journals, news release, Sept. 3, 2007