As shown in Figure 3, CAT levels were positively associated with HAMD-17 scores in patients with trBD depression (adjusted r = 0.83, P = .005), while SOD, GSH-Px, and MDA levels were not associated with HAMD-17 scores in patients with trBD depression (SOD, adjusted r = 0.46, P = .22; GSH-Px, adjusted r = 0.44, P = .23; MDA, adjusted r = 0.16, P = .69). Here, SOD1 is linked to major depressive disorder.