In conclusion, the present study reveals that overweight patients with MDD showed higher levels of IL-1α, IL-1RA, IL-3, CXCL10, TNF-α, and ICAM-1 compared to normal-weight patients with MDD, and BMI was positively correlated to the serum levels of IL-1α, IL-3, IL-6, IL-10, IL-12, IL-15, CXCL10, TNF-α, and ICAM-1 in MDD patients. Here, IL15 is linked to major depressive disorder.