Low Cortisol Levels May Predict PTSD Risk
Cathleen Henning Fenton

Researchers at the Veterans Affairs Medical Center (VAMC) in Bronx, NY, have been studying post-traumatic stress disorder (PTSD) in children of Holocaust survivors. A major conclusion of these studies is that these children have a higher risk of developing PTSD than other people. In a study presented in the August 2000 The American Journal of Psychiatry, the research group discovered that adult children with at least one parent who is a Holocaust survivor have low cortisol levels. The discovery could mean that low cortisol levels may be predictive of the development of PTSD.

Cortisol is a hormone that scientists associate with stress as well as chronic mood disorders. During times of stress, cortisol levels rise and then subside as the stress subsides. If stress is chronic or if a chronic mood disorder (anxiety, depression) is present, increased cortisol levels may indicate that the brain has become resistant to cortisol's effects, scientists believe.

One may wonder why, then, people with PTSD or the risk of developing PTSD would have lower cortisol levels. The VAMC research group theorizes that with PTSD, the brain may become hypersensitive to the effects of cortisol. The same area of the brain which may resist cortisol in people with chronic mood disorders, the hypothalamic-pituitary-adrenal (HPA) axis, appears to work differently in people with PTSD or the risk of having PTSD.

The study performed by the researchers at the VAMC involved 35 adult children of Holocaust survivors and 15 comparison subjects. All subjects were evaluated using various standard questionnaires. To determine whether the subjects' parents had PTSD, parents were interviewed directly (in 11 cases) or subjects completed a questionnaire created by the researchers. To test cortisol levels, urine samples were collected during 24-hour periods during times when subjects did not expect to be under stress.

Using the results of the questionnaire, researchers divided the subjects into three categories:

  • subjects without lifetime PTSD, whose parents did not have PTSD
  • subjects without lifetime PTSD, whose parents did have PTSD
  • subjects with lifetime PTSD, whose parents did have PTSD

Researchers made the following conclusions based on the questionnaires and tests:

  • Adult children of Holocaust survivors were more at risk of developing PTSD than the comparison subjects, even though lifetime traumatic experiences did not differ between these two groups.
  • 13 of the 35 offspring of Holocaust survivors had lifetime or current PTSD.
  • 25 offspring of Holocaust survivors had at least one parent with PTSD.
  • Cortisol levels were low in subjects with PTSD and who had a parent with PTSD, but where higher in subjects who had neither.

Ultimately, the researchers were able to determine that the low cortisol levels were associated with parental PTSD rather than the parent's exposure to trauma during the Holocaust. Additionally, the low cortisol levels could be associated with a risk of developing PTSD. Subjects exposed to trauma without developing PTSD did not necessarily have low cortisol levels, so exposure to trauma alone cannot be associated with lower cortisol levels.

The conclusions of the VAMC study will help scientists further understand PTSD and lead to newer treatments. By determining physiological differences in people who develop PTSD, researchers can understand why some people develop the disorder after traumatic experiences but others do not.

Reference: Yehuda R, Bierer LM, Schmeidler J, Aferiat DH, Breslau I, Dolan S (2000). Low cortisol and risk for PTSD in adult offspring of Holocaust survivors. Am J Psychiatry 157: 1252-59.