Researchers at Ohio State University say that they have found evidence suggesting that compounds found in the recreational drug marijuana may benefit the aging brain by reducing inflammation and possibly stimulating the growth of new brain cells.

Professor Gary Wenk and colleagues have already proven that a drug containing synthetic tetrahydrocannabinol (THC), the main psychoactive substance in marijuana, is able to improve memory in animals.  They are now working to uncover the mechanism behind THC's apparent memory boosting properties.

Their latest findings suggest that at least three receptors in the brain are activated by the THC-like drug. All three receptors are part of the endocannabinoid system, which plays a role in a variety of physiological processes including memory, appetite, mood, and pain response. Research suggests that when the THC-like drug binds to these receptors it helps the brain to curb inflammation whilst also stimulating the production of new brain cells, or neurons.

However, tests have also shown that the drug is not effective once memory impairment is already evident, thus meaning that the drug can only be used to guard against future memory impairment.

“Could people smoke marijuana to prevent Alzheimer's disease if the disease is in their family? We're not saying that, but it might actually work. What we are saying is it appears that a safe, legal substance that mimics those important properties of marijuana can work on receptors in the brain to prevent memory impairments in aging. So that's really hopeful,” Professor Wenk said in a news release.

News release: Scientists are high on idea that marijuana reduces memory impairment. Ohio State University. November 14th 2008.