Researchers can't seem to make up their minds about the long-term cognitive effects of marijuana. Some studies have shown that it reduces brain power and impairs working memory, while other studies are indicating that it can suppress brain inflammation and confer other neuroprotective properties. And now, perhaps quite surprisingly, a new study is suggesting that cannabinoids may prevent - or even reverse - the effects of brain aging, an important piece of insight that could lead to therapies for neurodegenerative diseases like Alzheimer's.
The study, which was conducted by Andras Biokei-Gorzo of the Institute of Molecular Psychiatry at the University of Bonn in Germany, suggests that marijuana use, or more accurately, the activation of the brain's cannabinoid system, may trigger the release of anti-oxidants, which act as a kind of cleansing mechanism. This process has been known to remove damaged cells and improve the efficiency of mitochondria.
Subsequently, it's the same process that's been known to slow down aging in the brain, and in some cases even reverse its effects.
Speaking to TIME, Biokei-Gorzo noted the implications: "[C]annabinoid system activity is neuroprotective [and increasing it] could be a promising strategy for slowing down the progression of brain aging and for alleviating the symptoms of neurodegenerative disorders."
But not everyone is thrilled about the idea. Some worry about potential negative psychoactive effects of marijuana on the elderly. Others are simply opposed to the use of cannabis on principle - because it's a controlled substance.
And as for the science itself, Biokei-Gorzo himself admits that his study has some gaps. Again, from TIME:
Moreover, some of the research covered in the review had conflicting results. Although three clinical trials studied cannabinoids for the treatment of Parkinson's Disease, these studies "did not provide a clear answer whether cannabinoids modify the progression or the outcome of the disease," wrote Bilkei-Gorzo. He found similar results for Huntington's Disease, which, like Parkinson's, is a progressive, degenerative brain disorder. And for the most common form of dementia, "Despite the promising preclinical results, the detailed clinical evaluation of cannabinoids in [Alzheimer's] patients is missing," he said in the paper.
Interestingly, Biokei-Gorzo and his colleagues say that the greatest hurdle for moving forward with their research are the social and political challenges. He says, "I've been trying to find a drug that will reduce brain inflammation and restore cognitive function in rats for over 25 years; cannabinoids are the first and only class of drugs that have ever been effective. I think that the perception about this drug is changing and in the future people will be less fearful."
You can read the entire study at Philosophical Transactions of the Royal Society B.