Men with low testosterone levels are more likely to develop depression, according to an article in the February issue of The Archives of General Psychiatry.

Testosterone levels generally peak in early adulthood, decreasing by approximately 1 percent per year after age 40 years. Testosterone deficiency (hypogonadism) is common in older men, with a prevalence of 30 percent among men older than 55 years. Symptoms of hypogonadism include decreased muscle mass and strength, decreased bone mineral density, diminished appetite, decreased libido, fatigue and irritability. Some symptoms overlap with those of depression, but the association between hypogonadism and depression is unclear.

Molly M. Shores, MD, and her American colleagues examined the clinical records of 278 men age 45 years or older without depression to examine the relationship between testosterone level and the incidence of diagnosed depression over a 2-year period.

Over the study period, 21.7 percent of the hypogonadal men were diagnosed with depression compared with 7.1 percent of men with normal testosterone levels. When the researchers adjusted for age, alcohol use disorders, prostate cancer, and other medical conditions, they found that men with hypogonadism were 4.2 times more likely to be diagnosed with depression.

"Hypogonadal men showed an increased incidence of depressive illness and a shorter time to diagnosis of depression," the authors wrote. "Further prospective studies are needed to confirm these preliminary findings and to clarify the role of testosterone in the treatment of depressive illness in older men."