Dr. Michael Irwig, an associate professor of medicine at George Washington University in Washington, D.C., reported at a meeting of The Endocrine Society that men who are referred to an endocrinologist with low blood testosterone levels often show signs of depression.

In an investigation of 200 men with low testosterone, more than half were diagnosed with depression. Other factors that could have contributed to mood symptoms were lack of exercise and excess body weight.

Fifty-one percent of the men in the study engaged in no exercise aside from walking, while 39 percent were overweight, and 43 percent obese.

The subjects also had high rates of erectile dysfunction (89 percent) and low sex drive (69 percent).