Novel insights into depression and antidepressants: a synergy between synaptogenesis and neurogenesis?

Major depressive disorder has been associated with manifold pathophysiological changes. These include metabolic abnormalities in discreet brain areas; modifications in the level of stress hormones, neurotransmitters, and neurotrophic factors; impaired spinogenesis and synaptogenesis in crucial brain areas, such as the prefrontal cortex and the hippocampus; and impaired neurogenesis in the hippocampus. Antidepressant therapy facilitates remission by reversing most of these disturbances, indicating that these dysfunctions may participate causally in depressive symptomatology. However, few attempts have been made to integrate these different pathophysiologies into one model. The present chapter endeavors (1) to review the extant literature in the field, with particular focus on the role of neurogenesis and synaptogenesis in depression; (2) and to suggest a possible interplay between these two processes, as well as, describe the ways by which improving both neurogenesis and synaptogenesis may enable effective recovery by acting on a larger neuronal network.