Low Testosterone May Cause Depression
Clinical Depression Often Unrecognized in Older Men
Feb. 3, 2004 -- Low testosterone levels may cause clinical
depression in older men, a new study shows.
Age related decreases in the male sex hormone testosterone are
common in older men; some 30% of men over age 55 have it. Low levels of the
hormone can cause symptoms of fatigue, a decreased sex drive, and irritability.
However, because some symptoms of this disorder are similar to symptoms of
depression, the link between the two disorders has been unclear.
In this study, researchers analyzed medical records over a
two-year period for 278 men -- all age 45 and over -- who had no diagnosis of
depression before that time period. These were also men who had low or normal
levels of testosterone test results. Doctors often order these tests when there
are libido or other sexual function problems.
During the two-year period, the men with low testosterone were
four times more likely to be diagnosed with clinical depression, reports
researcher Molly M. Shores, MD, with the Veterans Affairs Puget Sound Health
Care System and the University of Washington in Seattle.
Her study appears in the Archives of General
Older Men at Risk
This might happen because low testosterone levels trigger
symptoms such as anorexia, fatigue, and decreased libido, which may have an
effect on mood.
Or, as one study of mice showed, low testosterone may directly
alter brain chemistry -- specifically serotonin levels. Studies of humans show
that serotonin levels are lower in older adults with clinical depression.
"Older men would be particularly vulnerable to these
effects, because serotonin receptors are already decreased from normal
aging," writes Shores.
Primary care doctors often don't recognize depression in these
patients. And testosterone levels are rarely checked when signs of clinical
depression are evident, she explains.
"Because depression is a major risk factor for suicide, and
older men have the highest suicide rate of any age group in the United States,
identifying conditions [such as low testosterone] that increase the risk of
depressive illness could be an important opportunity for early intervention and
treatment," she writes.
Treatment for both clinical depression and low testosterone
could improve quality of life for older men, she writes. However, questions
remain about the risks of prostate cancer related to testosterone replacement
therapy -- which future studies need to address, says Shores.