Men who are severely depressed have lower levels of the male hormone testosterone than men who are not depressed, German investigators report.
They also note that depressed men also have much higher levels of another hormone, cortisol, than healthy male subjects. The lower the testosterone levels, the higher the levels of cortisol, a hormone linked to stress.
Dr. Ulrich Schweiger and colleagues from the Max Planck Institute of Psychiatry in Munich, Germany, compared blood levels of testosterone and other hormones in 15 men hospitalized for severe depression with levels in 22 nondepressed male ''control'' subjects. Blood samples were taken every half-hour during the day, every 10 minutes from 6 p.m. to midnight, and every 30 minutes from midnight to 7:30 a.m.
After matching men for age, the researchers found that testosterone levels were lower in severely depressed subjects than in normal male controls during the day, at night, and across the 24-hour sampling interval. Cortisol levels were also 68% higher in depressed subjects compared with normal controls.
But the investigators note that it is still not known if low levels of testosterone contribute to either the symptoms or the development of depression.
On the other hand, low testosterone levels may help explain why sexual function is often impaired in depression.