TNF and major depressive disorder: Numerous studies have shown that depression is accompanied by the activation of the inflammatory response system, with changes in pro-inflammatory cytokine levels in the brains of depressed patients, such as increased secretion of interleukins (IL) and tumor necrosis factor (TNF), particularly elevated levels of IL-1β, IL-6, and TNF-α (Jung et al., 2023; Li et al., 2024).