Cannabis-Related ED Visits May Raise Dementia Risk: Daily Dose

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Patient Care brings primary care clinicians a lot of medical news every day—it’s easy to miss an important study. The Daily Dose provides a concise summary of one of the website's leading stories you may not have seen.

On April 16, 2025, we reported on a study published in JAMA Neurology that was designed to investigate the association between emergency department (ED) visits or hospitalizations due to cannabis and future dementia diagnosis.

The study

The retrospective population-based study matched 15 120 adults aged 45 to 105 years living in Ontario with cannabis-related acute care with 125 704 with all-cause acute care. The primary outcome, a diagnosis of dementia, including Alzheimer disease, was identified using validated assessment tools and ICD-10 coding.

Researchers used cause-specific adjusted hazard models to compare new diagnoses of dementia between participants with acute care due to cannabis use with:

• Individuals with all-cause acute care (excluding cannabis),

• the general population, and

• individuals with acute care due to alcohol use.

The findings

After multivariable adjustment for sociodemographic factors and chronic health conditions, researchers found that individuals who had an ED visit or hospitalization due to cannabis use remained at a 23% (adjusted HR, 1.23, 95% CI, 1.09-1.39) greater risk of a new dementia diagnosis compared to those with acute care for any other cause, and at 72% (aHR 1.72, 95% CI 1.38-2.15) greater risk compared to the general population.

Among individuals aged 45 to 64, the annual rate of such visits increased more than 5-fold over the study period, from 6.9 per 100 000 individuals in 2008 to 37.6 per 100 000 in 2021. Among individuals aged 65 and older, the increase was even more striking—rising 26.7-fold (from 0.65 to 16.99 per 100 000).

Authors' comments

"Our results should not be interpreted as showing that cannabis use in patterns sufficient to result in an ED visit or hospitalization due to cannabis cause dementia. However, regardless of causality, our findings have clinical implications highlighting a group at high risk of developing dementia who may benefit from close follow-up and intervention or preventive efforts."

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