GSTM1 and major depressive disorder: Interestingly, the mtDNAcn of the BD group was significantly positively correlated with mean VFT-related oxy-Hb changes in ch38 (rho = 0.660, Bonferroni-corrected P < 0.00096), while that of the MDD group was significantly negatively correlated (rho = −0.541, Bonferroni-corrected P < 0.00096; Figure 5).