Sexual function in men with epilepsy: how important is testosterone?

OBJECTIVE: To ascertain the effects on sexual function of men with epilepsy (MWE) of testosterone levels and indices of anxiety and depression.

METHODS: Sixty MWE taking one antiepileptic drug only (AED), with no comedication, were compared with 60 control men. Total testosterone (TT), free testosterone (FT), bioactive testosterone (BAT), dehydroepiandrosterone sulfate (DHEAS), androstenedione, and sex hormone-binding globulin (SHBG) were measured. Each man also completed validated questionnaires exploring sexual desire (Sexual Desire Inventory [SDI]), sexual response (Sexual Response Inventory [SRI]), erectile function (Sexual Self-Efficacy Scale [SSES]), and anxiety and depression (Hospital Anxiety and Depression Scale).

RESULTS: MWE reported lower levels of sexual desire and lower erectile function compared with controls. They had significantly higher levels of anxiety, depression, and psychological distress. MWE had significantly higher SHBG levels and significantly lower DHEAS. There were no significant differences between the groups' TT, FT, or BAT levels. BAT levels were significantly lower in men taking enzyme-inducing AEDs than in those taking non-enzyme-inducing AEDs. Visual inspection of TT and BAT levels showed that the majority of MWE and controls had TT and BAT levels above the "androgen threshold" levels of 12 nmol/L TT or 3.8 nmol/L BAT considered necessary for normal sexual function. There was a significant correlation (Spearman rank and simple linear regression) between sexual function and indices of anxiety and depression. There was no significant relationship between SDI and SSES and TT, FT, or BAT (Spearman rank correlation).

CONCLUSIONS: Concentrating on hormone levels alone as an explanation of sexual dysfunction in epilepsy represents an overly simplistic approach to the problem. Future studies should include measures of quality of life, anxiety, and depression.