Alcohol,testosterone and suicide

To the Editor

Multiple lines of evidence suggest that heavy alcohol use is associated with suicide attempts and completed suicides. It has been proposed that suicidal behavior in individuals with alcoholism is related to certain neurobiological mechanisms, including serotonergic abnormalities (Gorwood, 2001). However, the pathophysiology of suicidal behavior in alcohol use disorders remains unclear.

There is evidence that low testosterone levels in older men may contribute to the psychobiology of suicidal behavior (Sher, 2013). Studies show that in older men, decreased testosterone levels are associated with depression and diminished cognitive abilities, whereas higher blood levels of testosterone are associated with enhanced mood and better cognitive functioning. Depressive symptoms and decreased cognition are associated with suicidal behavior and may mediate the effect of decreased testosterone levels on suicidality. It is also possible that, in older men, low testosterone levels are directly linked to suicidal behavior via some brain mechanisms.

Alcohol has been shown to decrease testosterone release from Leydig cells (Herman et al., 2006). The mechanisms responsible for this phenomenon probably include decreased activity of the luteinizing hormone-releasing hormone (LHRH)–LH axis, as well as a direct influence of alcohol on the testes. Studies have shown that the inhibitory influence of alcohol on the hypothalamic-pituitary-gonadal axis of laboratory rodents, primates, and humans can include decreased LHRH synthesis because alcohol easily crosses the blood–brain barrier, and/or the inhibition of testicular proteins essential for sex steroid synthesis because alcohol readily penetrates the testicles. There is also evidence that alcohol might stimulate a pituitary-independent, neural pathway between the hypothalamus and the testes, whose activation diminishes testosterone secretion. Alcohol-induced suppression of testosterone release from Leydig cells leads to a reduction in blood testosterone levels.

Therefore, it is reasonable to hypothesize that an alcohol-induced decrease in testosterone levels may contribute to suicidal behavior in older men using/abusing alcohol. If this hypothesis is correct, testosterone supplementation may reduce suicidality in older men with alcohol use disorder. Clearly, it is critical to treat and to prevent alcohol misuse in older men.