Second, there might be a potential effect of medication on the plasma α-Klotho levels in MDD patients in this study since we do not have a full treatment record for these patients from the biobank of Anding hospital and could not provide direct analysis of medication/treatment effect on plasma α-Klotho levels in MDD patients in this study, except having some discussion on potential medication involvement. The gene discussed is KL; the disease is major depressive disorder.