A large, landmark study tracked more than 6 million people age 45 and up. Most recently, it uncovered shocking connections between chronic cannabis consumption and dementia. A new study done in Canada and published in JAMA Neurology paints a terrifying picture. Those who required acute care due to cannabis use were much more likely to develop dementia within five to ten years post-hospitalization.
This study illustrates a very alarming pattern. People who used emergency medical services for cannabis-related conditions were almost four times more likely to have a diagnosis of dementia within five years compared to the general population. Five years later, 5% of these patients had received a diagnosis of dementia. By comparison, only 3.6% of those with all-cause acute care and only 1.3% of the general population had such diagnoses during that same time period. By the ten-year follow-up, the rate among those with severe cannabis use had increased to 18.6%.
Rebecca Edelmayer, vice president of scientific engagement at the Alzheimer’s Association, stressed that it isn’t so simple when it comes to dementia risk.
“Alzheimer’s disease and other dementias are very complex and have many risk factors. We need to look at dementia risk from all angles to truly understand it.” – Rebecca Edelmayer, PhD
Since that time that the use of medicinal cannabis was liberalised in 2014, the number of acute care cases has risen dramatically. This trend increased sharply after the legalization of nonmedical cannabis use in 2018. Hospitalizations for cannabis-related complications exploded from roughly seven to 38 per 100,000 persons from 2008 to 2021. The increase was even more stark among older adults, with a five times increase in those 45-64 and an incredible 26.7 times increase in those 65 and up.
Steve Allder, a consultant neurologist at Re:Cognition Health, described the study as groundbreaking due to its large sample size and longitudinal design.
“This is a landmark study due to its large sample size (over 6 million people) and longitudinal design. By examining dementia outcomes over this period, the researchers were able to provide insights into the long-term cognitive risks of cannabis use serious enough to result in emergency or hospital care.” – Steve Allder, MD
This suggests that cannabis is not a direct cause of dementia. It kind of makes sense, but it’s just really adding to this complicated risk web that includes vascular, psychological, and neurological factors. These interconnected risks, Allder noted, all increase a person’s risk of developing dementia.
“Importantly, the study suggests that severe cannabis use, rather than casual or moderate use, is linked to increased dementia risk. This reinforces concerns about rising cannabis use among older adults, especially as it’s increasingly used for both medical and recreational purposes.” – Steve Allder, MD
Specifically, long-term exposure to tetrahydrocannabinol (THC), the psychoactive component of cannabis, has been linked to numerous cognitive and learning deficits. THC affects the hippocampus—a brain area crucial for memory formation—and has been linked to reduced hippocampal volume, a hallmark of Alzheimer’s disease.
Chronic cannabis users typically demonstrate lower grey matter density in several significant brain regions. These areas are responsible for executive function, emotional control, and memory. Allder was interested in cannabis use’s potential to negatively affect neuroplasticity. It does so by reducing the circulation of brain derived neurotrophic factor (BDNF), which is known to damage white matter integrity and inhibit intra- and inter-network connectivity within the brain.
“Collectively, these structural and functional changes can undermine cognitive reserve and potentially accelerate age-related neurodegeneration.” – Steve Allder, MD
Implications from the study point to troubling issues around the growing popularity and usage of cannabis among older adults. This concern is increasingly timely as more and more states are loosening regulations on cannabis for medical and recreational use. In summary, the above evidence points to the urgent need of a larger understanding of risks associated with heavy cannabis use. It further underscores the long-term impact on cognitive health.
Leave a Reply