CXCL8 and major depressive disorder: Since several effective antidepressants such as amitriptyline and mirtazapine have been shown to increase cytokine production (Lichtblau et al., 2013), while treatment with duloxetine reduced serum concentration of the proinflammatory cytokines IL-8, IL-12, and interferon gamma, but not of TNF-alpha or IL-1 beta (Gao et al., 2024), this might have affected the relationship between cytokine levels and severity of MDD as assessed via the BDI in our study.