Emerging evidence indicates that proinflammatory cytokines, including interleukin (IL)-1, IL-6, and tumor necrosis factor-alpha (TNF-α), contribute to the pathophysiology of depression (Szkaradkiewicz et al. 2009; Grivennikov and Karin 2011; Felger and Lotrich 2013). This evidence concerns the gene IL6 and major depressive disorder.