TNF and major depressive disorder: Several potential pathways such as endothelial function disturbance, inflammation with pro-inflammatory cytokines (IL1β, IL2, IL6), tumor necrosis factor-α (TNF-α), and C-reactive protein (CRP) increase, but also decline in the autonomic nervous system, and platelet abnormalities are involved as pathophysiological mechanisms connecting depression and cardiovascular diseases (CVDs).