Non-Medical Cannabis Use Linked To Dramatically Lower Cognitive Decline Risk In Adults Over 45

SYRACUSE, N.Y. — In a surprising new study, researchers have found that non-medical cannabis use is associated with a significantly lower risk of subjective cognitive decline (SCD) in adults 45 and older. SCD refers to an individual’s self-reported experience of worsening or more frequent confusion or memory loss. It’s often an early warning sign of impending cognitive impairment and dementia.

The study, conducted by researchers at SUNY Upstate Medical University, is published in Current Alzheimer Research. Zhi Chen, an assistant professor in the school’s Department of Public Health & Preventive Medicine, and Professor Roger Wong utilized data from the 2021 Behavioral Risk Factor Surveillance System, a national U.S. health survey. They examined the relationship between various aspects of cannabis use – including reasons for use, frequency, and methods of consumption – and the prevalence of subjective cognitive decline in over 4,700 middle-aged and older adults.

Interestingly, they found that compared to non-users, those who consumed marijuana for non-medical reasons had a whopping 96 percent lower odds of reporting SCD, even after adjusting for numerous demographic, health, and lifestyle factors. In other words, recreational cannabis users were much less likely to notice declines in their memory and thinking compared to their counterparts who abstained.

While medical marijuana use and using cannabis for both medical and non-medical reasons were also associated with reduced SCD risk, these relationships weren’t statistically significant. Additionally, how often someone used cannabis and the method of consumption (such as smoking, eating, or vaping) didn’t appear to impact subjective cognitive decline odds.

So, what might explain this novel and unexpected finding? The researchers propose a few potential mechanisms. Tetrahydrocannabinol (THC), the main psychoactive compound in marijuana that produces the “high,” could play a role. Some animal studies have hinted that very low doses of THC might improve cognitive function in older mice, though whether this translates to humans requires further study.

Another factor to consider is that many people turn to cannabis, particularly the non-psychoactive compound cannabidiol (CBD), to help manage sleep disturbances and stress – both of which are risk factors for cognitive impairment in later life. If non-medical cannabis use helped improve sleep and lower stress, this could potentially contribute to better cognitive outcomes over time.

However, the researchers caution that these results are still preliminary, and more work is needed to tease apart the complex relationship between cannabis and cognition as we age. They note a few limitations of their study, including its reliance on self-reported data and the fact that it only looked at adults 45+, so the findings may not apply to younger folks.

“The main takeaway is that cannabis might be protective for our cognition, but it is really crucial to have longitudinal studies because this is just a snapshot of 2021,” says Wong in a university release. “We do not know if non-medical cannabis leads to better cognition or the other way around if those with better cognition are more likely to use non-medical cannabis. We need longitudinal studies to see long term if non-medical cannabis use is protecting our cognition over time. That’s something we don’t know yet, but that research is hindered since cannabis remains illegal federally.”

The study also found that higher education, better physical and mental health, and lack of heart disease history were linked to lower SCD risk – findings that align with prior research. This underscores the importance of overall healthy aging in protecting brain health over the lifespan.

Still, this study adds an intriguing new dimension to the conversation around cannabis and cognition in older adults. While “reefer madness” propaganda of the past portrayed cannabis as unequivocally detrimental to memory and thinking, the reality may be more nuanced.

Of course, this doesn’t mean that older adults should start sparking up joints in hopes of staving off dementia. Marijuana use can come with risks and side-effects, especially in high doses or among those with certain medical conditions. Due to federal prohibitions, cannabis products aren’t regulated for quality and may contain contaminants or inaccurate labeling.

However, as more states move to legalize and destigmatize cannabis, and a growing proportion of adults use it medically and recreationally, it’s crucial that scientists continue to investigate its potential benefits and harms for the aging brain. With Alzheimer’s disease and related dementias on the rise as our population grays, any clues to preventing or delaying cognitive decline are valuable indeed.

In the meantime, experts recommend focusing on the many evidence-based pillars of brain-healthy living as we age: staying physically active, eating a nutritious diet, getting enough sleep, managing stress, staying socially connected, and engaging in mentally stimulating activities. While the jury is still out on cannabis’ cognitive effects, these tried-and-true habits are a solid foundation for a lifetime of healthy aging – both in body and mind.