Unadjusted analyses demonstrated a positive association between ALT/AST ratio and depression when categorized by quartiles (Q4 vs. Q1: OR = 1.96, 95% CI: 1.49–2.59, P < 0.001), persisting after adjustment (adjusted OR = 2, 95% CI: 1.4–2.86, P < 0.001). Here, GPT is linked to major depressive disorder.