Calculated bioavailable testosterone levels and depression in middle-aged men

BACKGROUND: The association between circulating total testosterone (TT) levels and depressive symptoms remains unclear. We sought to determine the relationship between physiologically active bioavailable testosterone (BT) and depressive symptoms in middle-aged men with and without major depressive disorder (MDD). METHODS: We assessed and compared calculated BT levels in two groups of middle-aged men (40-65 years): untreated subjects meeting DSM-IV-TR-defined criteria for a major depressive episode as part of major depressive disorder (N=44) and a matched non-depressed control group (N=50). RESULTS: Depressed men had lower mean BT levels (3.51+/-1.69 vs. 4.69+/-2.04 nmol/L; p=0.008) and TT levels (11.94+/-4.63 vs. 17.64+/-1.02 nmol/L; p<0.001) when compared to the control group. Biochemical hypogonadism (i.e., BT level< or =2.4 nmol/L or TT level< or =12.14 nmol/L) was also more prevalent in depressed men vs. non-depressed controls (34% vs. 6%, p<0.001; 61% vs. 14%, p<0.001, respectively). CONCLUSIONS: Changes in physiologically active BT concentration may be a vulnerability factor for depressive symptoms in middle-aged depressed men.