In view of these results, we measured the levels within the HPC of different factors known to regulate adult HPC neurogenesis and to have an important function in the pathophysiology of depression, namely brain derived neurotrophic factor (BDNF), transcription factor cAMP response element-binding protein (CREB) and Forkhead Box O transcription factor (FOXO). This evidence concerns the gene CREB1 and depressive disorder.