Venlafaxine inhibits the upregulation of plasma tumor necrosis factor-alpha (TNF-α) in the Chinese patients with major depressive disorder: A prospective longitudinal study

Although tumor necrosis factor-alpha (TNF-α) has been recognized to be involved in the pathogenesis of major depressive disorder (MDD) for a long time, only few studies so far investigated the effects of antidepressant, venlafaxine on TNF-α and the results are inconsistent. Moreover, the association between plasma TNF-α levels and suicide accompanied with MDD is entirely unknown. To elucidate these relationships, in the present study, 64 first-episode drug-naïve MDD patients and 64 matched healthy controls were recruited. Total 61 MDD patients received 8-week venlafaxine treatment and they were divided into responders and non-responders according to the reduction rate of HRSD-17. Prior to venlafaxine treatment, both responders and non-responders shared a similar plasma TNF-α (p = 0.33), which was significantly decreased following venlafaxine treatment (p < 0.001, p = 0.03, respectively). Compared to non-responders, the responder group had a greater reduction in TNF-α (p = 0.01), which was associated with the greater reduction rate of HRSD-17 (B = 1.02, p = 0.01). In addition, the plasma TNF-α levels were equally higher in both suicidal and non-suicidal MDD patients (p = 0.84) compared to the healthy controls on admission (p = 0.001, p = 0.03, respectively). Together, our data suggest that MDD per se rather than suicide is associated with the elevated plasma TNF-α, which can be inhibited with venlfaxine monotherapy. The extent of TNF-α reduction may be associated with the efficiency of venlafaxine.