Depression in Women has Possible Biological Explanation

Certain stress hormones appear to have a stronger effect on women than men, so that the same low levels of stress are more likely to induce depression in women than in men. This finding represents the first evidence that there may be a biological basis for the higher rates at which women are diagnosed with depression. Women are more than twice as likely as men to be diagnosed with depression and other stress-related disorders.

A new study conducted by neuroscientists at the Children’s Hospital of Philadelphia, which appeared earlier this week in the journal Molecular Psychiatry, found both that low levels of one stress hormone have more effect on females and that females are less able to become accustomed to high levels of the hormone than males.

The research is still at a preliminary level.  The current study, led by Rita Valentino and Debra Bangasser, examined the brains of female and male rats and focused on a hormone called corticotropin-releasing factor or CRF, which regulates the response to stress in mammals.

After exposing the rats to a swimming stress test, the researchers found that the female rats’ brains were more response to CRF than the male rats’ brains. After extended exposure, the male rats actually became less responsive to CRF, but this same adaptation did not occur in the female rats’ brains.

Although the research will need to move on to the study of humans, according to Dr. Valentino, researchers already know that the function of CRF is an important factor in various stress-related psychiatric disorders, so the finding may well point to important differences that need to be taken into account in understanding stress disorders for women and in developing antidepressant medications.

Surprisingly, even in rodent studies, researchers have tended to use only male rodents, which could explain why the important difference between the sexes in terms of handling stress hormones would have been missed previously.

The study was funded by the National Institutes of Health and co-authors included researchers at the Children’s Hospital of Philadelphia and the Farber Institute for Neurosciences of Thomas Jefferson University.