Decreased levels of BDNF have been detected post mortem in the cortex, hippocampus and nucleus basalis of Meynert in patients suffering from Alzheimer’s disease (Holsinger et al. 2000; Tapia-Arancibia et al. 2008), while region-specific down but also upregulation of BDNF has been shown in major depressive disorder patients (Krishnan et al. 2007; Pandey et al. 2008). This evidence concerns the gene BDNF and major depressive disorder.