Can Marijuana Help—or Even Improve—the Brain of Older Adults?

Two years ago, Scientific American released a startling story that took social media by storm. The story was based on a research study done on aging mice which found that delta-9 tetrahydrocannabinol (THC for short), the active ingredient in marijuana that can cause psychoactive effects and cognitive impairment, can have a positive effect on the hippocampus part of the brain which controls memory and learning.

Researchers didn’t stop with testing aging mice; they also performed similar tests on young and mature (middle-aged) mice. In the young mice, those exposed to THC exhibited cognitive impairment. In other words, they acted stoned. Whereas the older mice actually exhibited some signs of benefiting from marijuana use, such as sprouting additional synaptic spines, thereby increasing communication between neurons—resulting in more efficiently working brain cells.

The study has fueled discussions about the possibility that cannabis may help the brains of older adults function better. While this may seem hard to believe, it appears that THC and other external “cannabinoids” found in cannabis plants have the capacity to act as anti-aging molecules, or at least, improve cognitive function.

It could be a matter of enhancing what we already have. For years, medical professionals have known that our human brains naturally contain lots of marijuana-like molecules, called endogenous cannabinoids which activate specific brain receptors. While we have plenty of these when we are young, they decrease as we age. Therefore, it makes sense the brains of older people, who have naturally lost their endogenous cannabinoids over time due to aging, may indeed benefit from the THC supplied by marijuana and resulting additional cannabinoids (keeping in mind that this study was done on mice and not humans, so this has yet to be fully proven). Research aside, there is a distinct trend of older adults embracing marijuana use (and not just for medicinal purposes) in the 11 states and the District of Columbia where it is now legal. In California, where possession and recreational use of cannabis became officially legal on January 1, 2018, older adults are turning to cannabis use in record numbers according to this story in AARP. According to a 2018 Gallup poll, 58 percent of Americans 55 and older now say smoking pot is morally acceptable. Perhaps these older adults have simply figured out something when it comes to cannabis use, whether it’s to relieve aches and pains, relax and have a good time, or possibly giving their brain a little boost now and then.

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Institute on Aging

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