“Hippocampal neurogenesis is suppressed following chronic administration of the major drugs of abuse (including opiates, alcohol, nicotine, and cocaine). However, CB1-knockout mice display significantly decreased hippocampal neurogenesis, suggesting that CB1 receptors activated by endogenous, plant-derived, or synthetic cannabinoids may promote hippocampal neurogenesis. Cannabinoids can regulate the proliferation of hippocampal NS/PCs by acting on CB1 receptors. They found that both the synthetic cannabinoid HU210 and the endocannabinoid anandamide profoundly promote embryonic hippocampal NS/PC proliferation. Chronic, but not acute, HU210 significantly increases the number of newborn hippocampal neurons in adult rats by promoting NS/PC proliferation. A significant increase was observed in the hipoppocampal newborn neurons of mice following twice-daily HU210 injection for 10 days. This suggests that cannabinoids are the only illicit drug that can promote adult hippocampal neurogenesis following chronic  administration.” “Cannabinoids promote embryonic and adult hippocampus neurogenesis and produce anxiolytic- and antidepressant-like effects.” https://www.jci.org/articles/view/25509 http://www.science20.com/science_why_not/blog/chronic_high_doses_cannabinoids_promote_hippocampal_neurogenesis]]>