Six DRGs (FOSL1, SRF, JUN, TFAP4, SOX9, and HLF) and 16 TF2target DCLs appear to be the key differential factors in MDD; in contrast, one DRG (PATZ1) and eight TF2target DCLs appear to be the key differential factors in SSD. This evidence concerns the gene TFAP4 and major depressive disorder.