CREB1 and major depressive disorder: Also, antidepressants could elevate the levels of various growth factors within the hippocampus, potentially through the modulation of cyclic adenosine monophosphate (CREB) or other transcription regulators, which exerts a significant influence on the process of neurogenesis (Krishnan and Nestler, 2008), further indicating the importance of neurogenesis in combating depression.