The aging male: androgens, erectile dysfunction, and depression.

In contrast to women, men do not experience a sudden cessation of gonadal function comparable to menopause. However, there is a progressive reduction in hypothalamic-pituitary-gonadal (HPG) axis activity in aging men: testosterone levels decline and there is a loss of the circadian rhythm of testosterone secretion. Such progressive HPG-axis hypofunctioning is thought to be responsible for some signs and symptoms that are common in elderly men such as fatigue, reduced muscle and bone mass, sexual dysfunction, and depression. Yet, such presumed hypogonadal sequelae have not been correlated with testosterone levels. Unlike the profound effects of replacement therapy in young men with frank hypogonadism, testosterone replacement in men with age-related mild hypogonadism is not apparently effective in reversing these symptoms. This article reviews the relationship between androgens, sexual function, and depression in aging men.