Cannabis use is linked to a lower likelihood of experiencing subjective cognitive decline

In a new study published in Current Alzheimer Research, scientists have found that non-medical cannabis use is linked to a lower likelihood of experiencing subjective cognitive decline, a condition characterized by self-reported memory loss or confusion. This intriguing discovery sheds light on the complex relationship between cannabis use and cognitive health, particularly among middle-aged and older adults in the United States.

With the aging population and the rising prevalence of cognitive impairments, understanding the factors that can influence cognitive health is more crucial than ever. Subjective cognitive decline has been recognized as a potential early warning sign for more severe cognitive disorders, including dementia. At the same time, cannabis use is becoming more common, especially among older adults, prompting scientists to explore its potential impacts on cognitive function.

“There has been increasing attention about cannabis because more states continue to expand legalization, and subsequently more adults also have begun experimenting with the substance,” said study author Roger Wong, an assistant professor in the Norton College of Medicine at SUNY Upstate Medical University.

“I had noticed that most research on cannabis was only focusing on how frequency of cannabis use is associated with cognition. Thus, I expanded on prior research by examining how cognitive decline may result from different facets of cannabis use, such as reason (medical or non-medical), frequency (0-30 days/month), and method (smoke, vape, eat, etc.).”

For their study, the researchers analyzed data from the 2021 Behavioral Risk Factor Surveillance System (BRFSS), focusing on U.S. adults aged 45 and older. The BRFSS is a cross-sectional survey designed to collect information on health-related risk behaviors, chronic health conditions, and use of preventive services among American adults.

Specifically, this study zeroed in on respondents from Washington D.C. and 14 states that included the BRFSS cognitive decline module in their survey, resulting in an unweighted sample of 4,744 participants with valid responses on subjective cognitive decline.

Subjective cognitive decline, the study’s dependent variable, was assessed using a specific question from the BRFSS cognitive decline module: “During the past 12 months, have you experienced confusion or memory loss that is happening more often or is getting worse?”

Individuals who used cannabis for non-medical reasons reported significantly reduced odds of experiencing subjective cognitive decline compared to those who did not use cannabis. This suggests that non-medical cannabis use, as opposed to medical or mixed-use, might have a protective association against the self-perception of cognitive decline.

Interestingly, when examining the frequency of cannabis use and the methods of consumption (smoking, eating, drinking, vaporizing, or dabbing), the study found no significant association with subjective cognitive decline after adjusting for a comprehensive set of covariates. This finding indicates that the reason behind cannabis use (medical vs. non-medical) may be more pivotal in its relationship with subjective cognitive health than the quantity of use or the specific method of consumption.

Further analysis through multiple logistic regression models highlighted that, after controlling for various demographic, health, and substance use factors, non-medical cannabis use was associated with a 96% decrease in the odds of reporting subjective cognitive decline. This relationship remained consistent across different models, even after adjusting for a wide range of potential confounders.

“Non-medical cannabis use, such as for recreational purposes, may decrease cognitive decline, which is often a precursor to future diagnosis of dementia, which currently has no definitive prevention approach, no cure, and very limited treatment options,” Wong told PsyPost.

But the study has some limitations to consider. It didn’t account for potential geographical variations in cannabis legislation and use within the United States. The reliance on self-reported data, especially concerning cannabis use and cognitive decline, may introduce bias. Furthermore, the study’s focus on adults 45 years and older leaves unanswered questions regarding the impact of cannabis on younger populations.

Looking ahead, the researchers emphasize the need for further studies to explore the mechanisms underlying the observed association between non-medical cannabis use and reduced odds of subjective cognitive decline.

“We analyzed the U.S. CDC BRFSS (Behavioral Risk Factor Surveillance System) data, which has been collected annually since 1984,” Wong explained. “We specifically only analyzed the 2021 data since it contained the three cannabis measures. Thus, although our findings may suggest cannabis may be beneficial for cognition, it is imperative for future research to examine the relationship between long-term cannabis use and cognition. This is not feasible right now because cannabis remains illegal federally.

“Non-medical cannabis typically contains higher concentrations of a compound called THC, whereas medical cannabis typically contains higher concentrations of a compound called CBD,” the researcher added. “It is theorized that non-medical cannabis is being used for stress relief and improve sleep, which my prior research has found sleep disturbances to be a major risk factor for dementia.”

The study, “Association Between Cannabis Use and Subjective Cognitive Decline: Findings from the Behavioral Risk Factor Surveillance System (BRFSS),” was authored by Zhi Chen and Roger Wong.