Why women are more vulnerable to psychiatric stress

Reported June 21, 2010

It’s well known that women are more susceptible to some kinds of psychiatric disorders than men. For instance, studies have found that depression and post-traumatic stress disorder are twice as common among women as among men. But why?

Rodent One theory involves a brain hormone called corticotrophin-releasing factor, or CRF. It is responsible for kicking off the stress response, and it is regulated by the female sex hormone estrogen. So perhaps estrogen causes female and male brains to respond differently to CRF.

To test this, scientists at Children’s Hospital of Philadelphia and the nearby Thomas Jefferson University subjected male and female rats to a swim stress test. Then they studied their brains in minute detail.

It turned out that the female rats were more responsive to CRF – it registered more strongly in their brains than it did in the male rats. What’s more, the female rats weren’t able to tone down the hormone after their stressful swims. But the male rats were – their brain cells changed in a way that prevented some of the CRF from doing its usual job.

“The findings identify molecular and cellular mechanisms that could result in enhanced sensitivity of female rats to CRF and a decreased ability to adapt to excessive CRF,” the researchers wrote. But they cautioned that further research is needed to see if the same gender differences are at play in human brains.