Scholars Zhang et al. found that patients with higher levels of tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) are prone to depression and that TNF-α and IL-6 show a positive association with the occurrence of depression [9]; i.e., the lower the level of inflammatory factors, the less likely the patient has concurrent depression. The gene discussed is TNF; the disease is major depressive disorder.