Subjects with unipolar depression have a significant and positive relationship of CRP serum levels with the “concentration difficulties” item (Rho = 0.262), and IL-6 also with the items “concentration difficulties” (Rho = 0.278) and “lassitude” (Rho = 0.345) on the MADRS Depression Rating Scale (Table 8). Here, IL6 is linked to major depressive disorder.