J Korean Soc Biol Ther Psychiatry.  2020 Feb;26(1):5-13.

Depression and Anxiety Disorder in Perspective of Neurogenesis and Pattern Separation

• Lee H
• Kim YT

Abstract

Major depressive disorder (MDD) and anxiety disorder (AD) are mental disorders with a high social burden. Since the discovery of neurogenesis, one effect of anti-depressant was revealed as increasing the neurogenesis of the dentate gyrus (DG). Thus, many researchers have speculated that neurogenesis may correlate with the pathogenesis of depression and anxiety disorders. It was reasonable to hypothesize that neurogenesis would be essential for the therapeutic mechanism. We call this new hypothesis the neurogenic theory. In this review, we investigated the validity and evidence of neurogenic theory through post-mortem studies and animal models. As a result, it seems to be a lack of strong evidence to claim that the defect of neurogenesis itself causes MDD and AD. However, neurogenesis seems to be essential, at least for improving depressive or anxiety behaviors. From the algorithmic perspective, we also discussed the pattern separation, suggested function of neurogenesis of the DG, in the relationship with the symptoms of mental disorder. We tried to show that it is appropriate to interpret the relationship between neurogenesis and mental disorder using the term “overgeneralization” rather than the theoretical term “pattern separation”. Overgeneralization was especially beneficial for interpreting the relationship between the defect of neurogenesis and post-traumatic stress syndrome (PTSD) among AD. It is necessary to further investigate the effect of neurogenesis in the treatment of mental illnesses such as MDD and AD including PTSD, and in the prognosis of patients.

Keyword

Depression; Anxiety disorder; Neurogenesis; Pattern separation; Overgeneralization