Testosterone levels low in depressed middle-aged men

21 November 2006

Middle-aged men with depression have lower levels of bioavailable testosterone and circulating total testosterone compared with other men, study findings show.

Thus, "changes in physiologically active bioavailable testosterone concentration may be a vulnerability factor for depressive symptoms in middle-aged depressed men," say Sidney Kennedy and colleagues from the University of Toronto in Ontario, Canada.

Noting that age-related decline in total testosterone concentration is associated with a symptom complex similar to that of a major depressive episode, including fatigue, irritability, dysphoria, and loss of libido, the researchers investigated the relationship between testosterone and depression in 94 men aged between 40 and 65 years.

Among the participants, 44 had major depressive disorder, while the remaining 50 did not.

Men with depression had lower bioavailable testosterone levels than controls, at 3.51 nmol/l versus 4.69 nmol/l, respectively. Similarly, total testosterone levels were lower in these men than in their non-depressed peers, at 11.94 nmol/l and 17.64 nmol/l, respectively.

Based on threshold levels of 2.4 nmol/l and below for bioavailable testosterone, 34% of men with depression were considered to have biochemical hypogonadism compared with 6% of non-depressed men.

The corresponding percentages based on a total testosterone threshold level of 12.14 nmol/l and below were 61% and 14%.

The investigators stress that the average androgen levels in the men with depression were in the low-normal range and not below normal.

"The results herein indicate that untreated depressed middle-aged men may exhibit hypothalamic-pituitary-gonadal axis hypofunctioning as evinced by lower bioavailable testosterone levels," say Kennedy et al in the journal Psychoneuroendocrinology.

They note, however, that the alternative hypothesis proposing that blunted androgen levels are a consequence of depression cannot be ruled out.

"Low testosterone is associated with depression, even when you control for the effects of age," said Kennedy.

"It supports a trend that was generally uninformed by research, that there may be some merit in adding a testosterone supplement in the treatment of depression, particularly if men report low libido."



Source: Psychoneuroendocrinology 2006; 31: 1029–1035