“Advocates for medical marijuana can take heart over the findings of two Canadian research teams.

A synthetic cannabinoid — similar to the compounds found in marijuana, but substantially stronger — causes the growth of new neurons and reduces anxiety and depression, investigators at the University of Saskatchewan here reported.

And researchers at the University of Calgary said they’ve found evidence that the brain contains so-called CB2 cannabinoid receptors, previously seen in immune tissue but thought not to exist in brain tissue. The discovery, they added, could lead to new drugs to treat nausea associated with cancer or AIDS.

Most so-called drugs of abuse — such as alcohol or cocaine — inhibit the growth of new neurons, according to Xia Zhang, M.D., Ph.D., of the University of Saskatchewan.

“Only marijuana promotes neurogenesis,” Dr. Zhang said.”

http://www.medpagetoday.com/Psychiatry/AnxietyStress/1934

“Cannabinoids promote embryonic and adult hippocampus neurogenesis and produce anxiolytic- and antidepressant-like effects… In summary, since adult hippocampal neurogenesis is suppressed following chronic administration of opiates, alcohol, nicotine, and cocaine, the present study suggests that cannabinoids are the only illicit drug that can promote adult hippocampal neurogenesis following chronic administration.”  http://www.jci.org/articles/view/25509