NTRK2 and major depressive disorder: We focussed on genes that have been shown to be important in cognitive processes and are associated with stress and MDD, such as Bdnf and its receptor TrkB, D1-like receptors (Drd1 and Drd5) and Fmr1. In addition, we also included Fkbp5, which regulates GR sensitivity to GC, and overexpression of Fkbp5 has been associated with increased risk of anxiety and MDD in patients [111].