While many of the conversations surrounding marijuana revolve around younger generations and their patterns of use, a growing body of research is starting to include older adults in the conversation. Two recent studies show an increase in the use of marijuana among older adults and a link to various health conditions.

The first study, out of the University of California, included data from 15,689 adults 65 and older. This study found a sharp increase in the prevalence of marijuana use over the past-month among this population- rising from 4.8% to 7.0%. This study identified a link between this rise and various factors, including residing in a state with legal medical marijuana, being a woman, and several health issues such as heart conditions, diabetes, hypertension, in addition to other sociodemographic and clinical outcomes.

The second study out of Ontario, Canada, where marijuana has been legal for recreational use since 2018, used health data from over 6 million individuals and focused on adults aged 45 and older over a 14-year period to assess whether marijuana use that led to an emergency department (ED) visit or hospitalization could be associated with future dementia diagnoses.

The study showed that between the years of 2008 to 2021, marijuana-related emergency care increased dramatically in adults aged 65 and older, with a 26.7-fold increase. Even among adults aged 45 to 64, the rate increased fivefold. This surge reflects both the growing normalization of marijuana and the growing number of older adults experimenting with or becoming dependent on its use. But as use has increased, so too has concern about its potential consequences for brain health. The study found that those who required emergency care for marijuana-related reasons were significantly more likely to develop dementia. Within 5 years,  5% of marijuana-related acute care patients were diagnosed with dementia- compared to 3.6% among individuals with other types of hospital visits, and just 1.3% in the general population.

Even after adjusting for factors like age, gender, chronic health conditions and mental health history, the elevated risk remained: Compared to peers hospitalized for any reason, marijuana users had a 23% higher risk of dementia. Compared to the general population, their risk was 72% higher. By 10 years, nearly one in five (18.6%) of those with marijuana-related hospital visits had developed dementia.

Although the specific biological mechanisms are still unknown, many studies have shown an association between heavy marijuana use and memory and cognitive decline, and this study adds to the concern that long-term use, heavy use or cannabis use disorder (CUD) may also accelerate long-term neurodegeneration. With chronic marijuana exposure possibly altering the brain structure, reducing cognitive reserve and interfering with key processes involved in memory and learning, this growing use is leaving older adults more vulnerable due to age-related changes in the brain and the possibility of unknown interactions with other health conditions or medications. As marijuana use grows in this age group, targeted prevention and education strategies are urgently needed.

References:

Myran DT, Pugliese M, Harrison LD, Stall NM, Webber C. (2025). Risk of Dementia in Individuals With Emergency Department Visits or Hospitalizations Due to Cannabis. JAMA Neurology, 82(6):570–579. doi:10.1001/jamaneurol.2025.0530

Rao, M. (2025). Cannabis-related ED visits, hospitalizations tied to higher dementia risk. Neurology Advisor. https://www.neurologyadvisor.com/news/cannabis-related-ed-visits-hospitalizations-higher-dementia-risk/

2021 to 2023 saw rise in cannabis use by older adults. (2025). Clinical Advisor. https://www.clinicaladvisor.com/news/2021-to-2023-rise-in-cannabis-use-older-adults