Background: Two published case studies have reported SRI/SNRI-associated low testosterone levels. Apathy and low testosterone, observed during venlafaxine treatment in one report, both resolved upon venlafaxine discontinuation. No studies have investigated the effect of chronic SRI treatment on human testosterone levels. As decreased testosterone has several negative health effects, we conducted a pilot study investigating the effect of fluoxetine treatment on testosterone levels.
Methods: Fourteen depressive disorder patients in good health (BDI = 15) were studied. In addition, 4 non-depressed patients were studied. Testosterone levels were drawn, and an apathy questionnaire (under development, not yet validated) was administered at intake. Fluoxetine was provided (10 mg/day for 7 days then 20 mg/day). To measure outcome, a follow-up testosterone level was drawn after 1 month's treatment.
Results: Eleven depressed, and 3 non-depressed, patients completed the study. While there were large differences-both increases and decreases-in some individuals' testosterone levels after fluoxetine treatment, for the study population as a whole, there was no relationship (depressed patients, p = 0.4; non-depressed patients, p 0.3) between fluoxetine treatment and testosterone levels.In patients with BDI = 20, testosterone levels at intake were highly associated with intake apathy levels (p = 0.0033).
Conclusions: Further, larger, studies correlating changes in testosterone levels during SRI treatment with treatment response, apathy levels and possibly sexual dysfunction seem indicated.