TNF and major depressive disorder: ROC analysis showed that serum TNF-α levels display good discriminatory value in differentiating MDD patients from HCs, evidenced by significantly higher AUC values (0.812) with 80.77% sensitivity and 73.58% specificity at a cut-off value of 31.78 pg/ml along with a diagnostic odd ratio of 11.71 and Youden’s index of 0.543.