Women are more likely than men to have depression -- that is, until age 65, when the numbers become almost equal. Why? It may have to do with the drop in testosterone levels in older men, according to recent research reported in Archives of General Psychiatry (Volume 65, page 283).
The incidence of depression is higher in older adults. The National Institute of Mental Health's Epidemiologic Catchment Area Study, which focuses on several major geographical areas, estimated that at least one million of the nation's 31 million people age 65 and older suffer from major depression, and an additional five million have depressive symptoms that are severe enough to require treatment. Now a study in the Archives of General Psychiatry sheds light on a possible cause for the increase in depression in older men.
The study included nearly 4,000 men ages 71 to 89 who were given questionnaires about their health, underwent evaluation for depression and cognitive problems, and gave blood samples to determine their testosterone levels.
Five percent of participants had depression at the start of the study. The men were then grouped into five categories based on testosterone levels; researchers found that those in the lowest quintile were significantly more likely to be depressed than those in the highest quintile -- even after adjusting for other depression risk factors such as education level, body mass index, other physical illnesses, and cognitive function.
Testosterone binds to many receptors in the body, including those in the central nervous system, which may explain this potential link between the hormone and depression. However, clinical trials are needed to determine whether testosterone supplementation may be helpful for older men with depression.
