DDIT4 and major depressive disorder: Many studies have found that miR-124 regulated some important genes for major depressive disorder (MDD) such as cyclic AMP-responsive element-binding protein 1 (CREB1) (Yang et al., 2020), specificity protein 1 (SP1), DNA damage-inducible transcript 4 (DDIT4) (Wang et al., 2018), AKT1 substrate 1 (AKT1S1), nuclear receptor subfamily 3 group C member 1 (NR3C1) (Roy et al., 2017), and mitogen-activated protein kinase 14 (MAPK14) (Liu et al., 2018).