Compared with non-depressed individuals, patients with depression show elevated levels of proinflammatory cytokines, including interleukin-1(IL1), interleukin-6(IL6), and tumor necrosis factor-alpha(TNF-α) (6, 7), as well as the systemic inflammation biomarker C-reactive protein(CRP) (8). Here, CRP is linked to major depressive disorder.