TNF and depressive disorder: In clinical patients, the release of pro-inflammatory cytokines, especially interleukin-1 cytokines (IL-1) and tumor necrosis factor (TNF-), is higher in depressed patients compared with normal patients, indicating that inflammation plays an vital role in the pathophysiology of depression (Al-Hakeim et al. 2015; Eyre et al. 2016; Hannestad et al. 2011).