Post-traumatic stress disorder (PTSD) is estimated to affect almost eight million adults in the United States, and rates are twice as high in women as men.1 Experts point to a variety of factors that may explain this difference.
“Multiple factors including cognitive, behavioral, and physiological factors have been suggested to contribute to sex differences in the risk of developing PTSD following trauma exposure,” Ihori Kobayashi, PhD, a post-doctoral fellow at Howard University College of Medicine in Washington, D.C., and co-author of a review of research that explored the sex differences in sleep and PTSD, told Psychiatry Advisor.2 Until recently, however, scientific investigation of these variables has been inadequate.
“Traditionally, studies on PTSD have looked primarily at men or didn’t compare men versus women,” Sabra S. Inslicht, PhD, a professor at University of California at San Francisco and a psychologist at the San Francisco Veterans Affairs Medical Center, said. Newer research is beginning to close the gaps, including a 2014 study co-authored by Inslicht that was published in the journal Psychopharmacology.3 “Our research aims to enhance our basic understanding of sex differences in the biology of PTSD,” she added.
To explore potential differences in stress hormone responses, Inslicht and colleagues gave men and women with and without PTSD a drug called metyrapone to test the responses of their hypothalamic-pituitary-adrenal (HPA) axis and reproductive hormone systems. They measured levels of adrenocorticotropic hormone (ACTH), a “stress hormone that is part of the HPA axis and is released from the pituitary gland during stress, resulting in the release of cortisol,” said Inslicht.
The researchers found that there was a greater ACTH response in participants with PTSD, and the response was greater among women than men. They also found that the responses of the reproductive hormone progesterone and its metabolite allopegnanolone partially mediated the relationship between PTSD and ACTH responses in men and women.