Canadian researchers discovered that a cannabis-like chemical or cannabinoid found in marijuana stimulates brain cell growth and helps fight anxiety and depression, according to a study released online on October 13 in advance of print publication of the November issue of the Journal of Clinical Investigation.
The finding is in sharp contrast with the common belief that abuse or chronic use of additive drugs inhibits the growth of new brain cells, causes memory loss and impairs learning, among other problems. In this respect, marijuana may not be such an ordinary additive drug. Researchers cautioned that marijuana may be the only exception among the additive drugs.
In the study, Dr. Xia Zhang and colleagues at the University of Saskatchewan in Canada, injected a high dose of a cannabis-like in rats twice a day for ten days and found the marijuana chemical promoted the growth of new brain cells – a process known as neurogenesis in the hippocampus.
The hippocampus is the part of the brain that keeps generating new cells or neurons throughout one's lifetime. The hippocampus is associated with memory, depression and mood disorders. Previous studies found that depression is associated with the number of brain cells or neurons.
Dr. Zhang’s team researchers performed tests on rats and proved that the cannabis-like compound has anti-anxiety and anti-depressant effect. Rats treated with the marijuana compound twice a day for ten days had reduced anxiety and/or depression.
The researchers suggest that there is a positive correlation between increased generation of new brain cells and modified behavior following chronic cannabinoid treatment.
The study used a high dosage of a synthetic cannabinoid found in marijuana. It is unknown smoking marijuana may have the same effect.
Use of marijuana is common in many countries. "Cannabis (marijuana, hashish or cannabinoids) has been used for medical and recreational purpose for many centuries," researchers wrote in their article. "Cannabinoids appear to be able to modulate pain, nausea, vomiting, epilepsy, ischemic stroke, cerebral trauma, multiple sclerosis, tumors, and other disorders in humans and or animals."
Researchers suggest that the marijuana chemical may be used to fight anxiety and depression.