The impairments in glucocorticoid receptor (GR) negative feedback and the increased expression of retinoic acid receptor alpha (RAR-α) in the hypothalamus are central mechanisms involved in the dysregulation of the hypothalamus-pituitary–adrenal (HPA) axis and the resulting stress and depression-like behaviors (Hu et al., 2013). This evidence concerns the gene NR3C1 and major depressive disorder.