Using genetic variants as IVs, seven metabolites associated with depression risk were observed, including acetoacetate (P = 0.000853), isoleucine (P = 0.015693), glutamine (P = 0.018849), glucose (P = 0.033466), apolipoprotein A-I (P = 0.035992), glycoproteins (P = 0.037874), and urea (P = 0.043872). The gene discussed is APOA1; the disease is major depressive disorder.