Washington, Sept. 4 : People whose parents are Holocaust survivors with post-traumatic stress disorder (PTSD) have on average lower levels of the stress hormone cortisol than the adult offspring of parents without PTSD, according a small study.

Biological differences seen in individuals with PTSD, including low cortisol levels, could either result from exposure to a traumatic event or they could be present before such an event, and predispose patients to the condition, according to background in formation in an article published in the Archive of General Psychiatry, one of the JAMA/Archives journals.

"Once identified, such risk factors may prove to be useful as predictors of who will develop PTSD after exposure to trauma, or they may even identify potential new targets for prophylaxis [preventive therapy] and treatment," the authors write.

Led by Dr. Rachel Yehuda of the Mount Sinai School of Medicine and James J. Peters Veterans Affairs Medical Center in New York, a team of researchers studied 33 individuals whose parents had survived the Holocaust.

Based on the data gathered through a questionnaire completed by the offspring, the researchers further divided participants into groups based on whether at least one parent met criteria for PTSD. While 23 of the offspring had parents with PTSD, and 10 had parents without PTSD.

The participants' blood cortisol levels were measured every 30 minutes for a 24-hour period, and then were compared with the levels of 16 individuals whose parents were not Holocaust survivors. None of the participants had PTSD at the time of the study.

It was observed that people whose parents had PTSD displayed lower average cortisol levels over the 24-hour period than did individuals whose parents did not have PTSD or were not exposed to traumatic events. The researchers say that the decrease seemed specifically related to having a mother with PTSD.

"Offspring with parental PTSD also demonstrated changes in some chronobiological parameters previously identified as altered in trauma survivors with PTSD despite that no subject had PTSD at assessment," the authors write.

"However, the overall pattern of alterations observed in the offspring with parental PTSD did not follow that reported for PTSD, allowing differentiation between parameters associated with risk vs. those associated with PTSD pathogenesis (development)," they add.

The authors of the study say that their findings have clear clinical applications.

"Although the implications for PTSD prophylaxis cannot be specified from these results, they have clear clinical applications, including assessment of parental PTSD in patients with PTSD and evaluation of stressful events during pregnancy and early childhood," they say.

"Indeed, the data suggest that examination of epigenetic [environmental or other effect that does not change DNA] or in utero phenomena should be added to the search for genetic polymorphisms that may underlie individual differences that increase vulnerability to this disorder," they write. (With Inputs from ANI)