Narrator: This is Science Today. The adrenal glands produce about one hundred different steroid hormones, including one called cortisol. This stress-resisting hormone raises blood sugar, resists shock and fights infection. Dr. Owen Wolkowitz, a professor of psychiatry at the University of California, San Francisco, says it's also by far the most common type of steroid hormone given medicinally.

Wolkowitz: That's because cortisol turned out to have very good anti-inflammatory effects back in the late 1940s, early 1950s and that led to the development of prednisone and drugs like that.

Narrator: High levels of cortisol are also associated with major depression, but it's probably not the only steroid hormone related to depression. Wolkowitz is also looking into DHEA for some therapeutic benefit.

Wolkowitz: Part of the reasoning there is that DHEA actually has some anti-cortisol effects of it's own. So it may well be it's not only high cortisol or low DHEA, but it might be the ratio between them that might be important and that's not even considering the other 98 or so other steroids that we have yet to investigate.

Narrator: For Science Today, I'm Larissa Branin.