Cannabis and Dementia: Separating Headlines From Science

Does Cannabis Increase the Risk of Dementia? What the Science Actually Says

Recent headlines have raised concerns about whether cannabis use might contribute to dementia. These stories can be alarming for patients, caregivers, and families already navigating cognitive health issues. But when we look closely at the scientific evidence, a much clearer and far more reassuring picture emerges.

There is currently no credible evidence that cannabis use increases the risk of dementia.

Let’s break down where the concern came from, what stronger research actually shows, and what this means for people already living with dementia.

Where the Concern Came From

Much of the recent worry stems from a study published in JAMA Neurology. Media coverage suggested that individuals who visited the emergency room for cannabis-related reasons were more likely to receive a dementia diagnosis later in life. While the headline was eye-catching, the study itself has major limitations that make its conclusions easy to misinterpret:

1. It did not account for why individuals were in the emergency room. ER visits often reflect broader medical, psychiatric, or social challenges that independently increase dementia risk. 

2. It did not measure how much cannabis people used, how often, or if they used non-impairing cannabinoids such as CBD in addition to THC.

3. This study did not demonstrate causation. It is possible that these individuals were already experiencing early and subtle neuro-cognitive symptoms, such as poor sleep, moodiness, or anxiety, and were self-medicating with cannabis. 

In other words, the study cannot tell us whether cannabis contributed to dementia. It only shows an association between cannabis-related ER visits and later dementia diagnoses, likely reflecting poorer baseline health, which is already well known to increase dementia risk.

What Stronger Research Shows

When we turn to higher-quality research, especially long-term studies that follow people over many years, the findings are remarkably consistent and do not support the idea that cannabis increases dementia risk.

A study published in the American Journal of Epidemiology (1999) found "no significant differences in cognitive decline between heavy users, light users, and nonusers of cannabis. There were also no male-female differences in cognitive decline in relation to cannabis use. The authors conclude that over long time periods, in persons under age 65 years, cognitive decline occurs in all age groups. This decline is closely associated with aging and educational level but does not appear to be associated with cannabis use." 

Another study in the journal Drug and Alcohol Dependence (2016) examined the relationship between cannabis use and cognitive function in 1,897 mid-life adults by comparing individuals to themselves over time, looking at how their thinking changed during periods when they used cannabis versus when they didn’t. This method helps rule out many built-in differences between people, like genetics or personality, making the results more reliable. The researchers concluded that cannabis use was not associated with accelerated cognitive decline in mid-life.

In a recent study published in the Journal of Substance Abuse, over 4000 cannabis users were evaluated. Interestingly, baseline lifetime daily cannabis use was associated with improved verbal reasoning, but not with any significant changes in other cognitive tests. 

A 2024 study published in the journal Brain and Behavior found similar findings in 5,162 Danish men followed for over 44 years, reporting, "...we found no significant harmful effects of cannabis use on age-related cognitive decline."

Taken together, these studies strongly indicate that cannabis use does not increase dementia risk. Much of the public fear comes from misinterpreted findings or lower-quality observational data, not from the larger body of evidence.

What About Cannabis for People Already Living With Dementia?

Due to the Schedule I status of cannabis and the lack of research funding, we have been restricted from studying cannabinoids in almost all conditions. However, a growing body of clinical studies have looked at the use of cannabinoids to treat the symptoms of dementia. Across these studies, researchers have consistently reported improvements in symptoms that significantly affect quality of life for both those with dementia and their caregivers.  These studies report reductions in agitation, restlessness, aggression, resistance to care, “sundowning” behaviors, sleep disturbances and appetite. And as a bonus, every study that looked at caregiver burden found meaningful benefits.

The Bottom Line

• Cannabis use is not associated with an increased risk of dementia.

• Fear-based headlines are not supported by rigorous scientific evidence.

Medical Guidance Makes All the Difference

A wide range of cannabinoids are now available for medical use, including THC, CBD, CBG, CBDA, THCA, CBN, CBGA, CBN and CBDV. Determining the most appropriate cannabinoid profile, dose, and delivery method is especially importnat for older adults and individuals living with dementia. Medical guidance is essential to customize treatment to individual symptoms and sensitivities, minimize unwanted side effects and avoid potential drug interactions, particularly since many older adults take multiple medications. 

If you or a loved one is looking for symptom relief, GoldsteinWellness.com can help connect you with a licensed practitioner experienced with cannabinoid-based care.