These inflammatory mediators and downstream signaling pathways can trigger depression by affecting monoamine neurotransmitters, glutamic acid (Glu), the hypothalamus pituitary adrenal (HPA) axis, and neurotrophic factors (NTF) in the body (Fig. 1) [12, 15, 34, 37, 38, 82–87]. This evidence concerns the gene TNF and depressive disorder.