Rachel Yehuda of the Mount Sinai School of Medicine and colleagues studied 33 individuals whose parents had survived the Holocaust.

These study participants were further divided into groups based on whether at least one parent met criteria for PTSD according to a questionnaire completed by the offspring, Yehuda said.

Twenty-three of the children had parents with PTSD and 10 had parents without PTSD. The researchers measured the participants’ blood cortisol levels every 30 minutes for a 24-hour period, then compared them with the levels of 16 individuals whose parents were not Holocaust survivors. None of the participants had PTSD at the time of the study.

Children whose parents had PTSD displayed lower average cortisol levels over the 24-hour period than did those whose parents did not have PTSD or were not exposed to traumatic events, the study published Archives of General Psychiatry found.