BDNF and major depressive disorder: Several other miRNAs have been associated with MDD through the dysregulation of inflammatory genes (miR-155), glucocorticoid receptor (GR) activity decrease (miRNA-155), and reduction of the brain-derived neurotrophic factor (BDNF) by overexpression of miR-30-5p, miR-124a, miR-16, and miR-182 [5].