A recent Canadian study has raised an important red flag about the potential link between cannabis use and dementia, especially in adults over 45 who need emergency or hospital care tied to cannabis. The research revealed that among middle-aged and older adults, those seeking medical help for cannabis-related reasons were nearly twice as likely to develop dementia within five years compared to others in the general population. But while the findings are significant, they stopped short of directly proving that cannabis causes dementia.

With cannabis use becoming more common among older adults, this emerging evidence highlights the need for deeper investigation into its long-term effects on cognition, especially as public perceptions lean towards thinking of cannabis as harmless or even beneficial.

Cannabis Use and Dementia Risk

The study, published in JAMA Neurology, analysed the medical records of six million individuals aged 45 and over from Ontario, Canada, spanning from 2008 to 2021. A critical strength of this research was its size and ability to track patients over time. Importantly, all participants were dementia-free at the time the study began, giving researchers better insight into the timeline of cannabis use versus dementia diagnoses.

The shocking findings? Among individuals who required medical attention for cannabis use, 5% developed dementia within five years, compared to just 1.3% in the general population. Even compared with those who sought care for other conditions, cannabis users still had a 23% higher likelihood of developing dementia.

“This study adds an essential piece to the puzzle of cannabis and dementia,” said Dr Daniel T. Myran, lead author of the study and assistant professor of family medicine at the University of Ottawa. “But it’s only a signal—not definitive proof—that cannabis could be playing a role in cognitive decline.”

Dr Myran’s view was echoed by psychological expert Dr Madeline Meier of Arizona State University, who noted that the connection between cannabis and cognition is increasingly supported by research. “This study reinforces that cannabis isn’t always harmless,” Meier said, pointing to previous findings of memory, attention, and verbal learning impairments tied to high cannabis use.

Growing Cannabis Use Among Seniors

The study uncovered an eye-opening trend: cannabis-related medical visits among adults aged 45 and over increased fivefold between 2008 and 2021. Among adults over 65, the spike was even more striking, as visits rose 27-fold.

This rapid rise raises numerous questions, particularly around why older adults are turning to cannabis in such numbers. Experts increasingly suggest that people use cannabis to self-medicate for chronic pain, anxiety, or sleep disorders.. Yet, as Dr Myran warns, this dynamic could muddy the waters when trying to untangle whether cannabis use is contributing to dementia or whether early signs of dementia may be driving individuals to use cannabis.

The Link Between Cannabis and Cognitive Health

Does cannabis directly cause dementia? The answer, for now, is complicated. Despite this study’s findings, experts agree the picture isn’t straightforward. Researchers would need to study chronic cannabis users over longer periods and in greater detail to establish a causal relationship.

However, evidence does suggest that heavy, long-term cannabis use can have neurological implications. Brain imaging studies have identified structural changes in the brains of regular cannabis users—including regions tied to memory and attention. “Even without definitive proof, studies like this highlight potential risks that no one should ignore,” said Dr Meier.

Notably, alcohol misuse was associated with even higher dementia risk than cannabis in this study. This raises questions about substance abuse more generally and its impacts on brain health in ageing populations.

Why Is Dementia Risk Higher for Cannabis Users?

There are several possible explanations for the link between cannabis use and dementia diagnoses. Heavy cannabis users often have other risk factors for cognitive decline, such as smoking, poor cardiovascular health, or mental health disorders, which can compound their overall risk.

This is another reminder that the broader lifestyle and health profile of cannabis users likely plays a role in these findings. For example, lower socio-economic status or limited access to healthcare could contribute to differences in health outcomes.

Taking Cannabis Use Seriously

While the findings don’t establish cannabis as a direct cause of dementia, they certainly challenge the assumption that cannabis use is risk-free, particularly among older adults. This is especially important as many regions continue to normalize and legalize cannabis use.

For those in their 40s, 50s, and beyond, it’s worth thinking carefully about the long-term health implications of cannabis use, especially if there are underlying health conditions or a family history of dementia.

Source: NY TImes