(5) In OA participants, the composite indicator of BDNF, VEGF, and S100B differentiated MDD patients from controls with the area under the curve (AUC) value of 0.806, and the combined indicator of baseline BDNF and S100B distinguished trans-MDD participants from non-MDD ones with an AUC value of 0.806. Here, VEGFA is linked to major depressive disorder.