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]. Here, TNF is linked to depressive symptom measurement.