Adults over 40 who use cannabis regularly tend to score better on cognitive tests than those who’ve never touched it. They also tend to have physically larger brains. Those two facts, drawn from a single large 2026 dataset, sound like an obvious green light for using cannabis as you age, but the reality is considerably more specific than that.
The study in question comes from the University of Colorado Anschutz Medical Campus, led by clinical psychologist Anika Guha. Using brain scans and cognitive tests from the long-running UK Biobank project – a population health database drawing on health information from over 500,000 adults across the UK – researchers grouped 26,362 adults between 40 and 77 years old into no-use, moderate-use, and high-use categories based on lifetime cannabis exposure. Individuals with a history of cannabis use showed larger gray matter volumes and faster processing speeds compared to non-users in the same age group. Gray matter is the brain tissue most directly tied to thinking, memory, and decision-making – and it typically shrinks as we age.
On average, people in the moderate-use group showed larger volumes in several brain regions rich in cannabinoid receptors, including areas involved in movement, emotion, and memory. On the cognitive side, cannabis users usually performed better than people who had never used the drug on tests covering learning, short-term memory, processing speed, attention, and executive function. The study was observational and used existing population data, meaning the findings show correlation rather than proof that cannabis directly improves brain health – a point Guha herself emphasized in comments about the research.
What the Cannabis Aging Brain Research Actually Shows
The findings carry weight partly because of scale. Guha and her colleagues at the University of Colorado Anschutz Medical Campus leveraged large-scale data from the UK Biobank to examine the relationships between cannabis use, normative aging, and cognitive function among over 26,000 participants, making this study one of the most extensive investigations of the cannabis aging brain question published to date in the Journal of Studies on Alcohol and Drugs.
The findings reveal that cannabis use and healthy aging are associated with overlapping brain network configurations, particularly within the functional network connectivity between subcortical and sensorimotor regions. Cannabis users exhibited superior performance across multiple cognitive domains. One important detail embedded in the data: while alcohol is consistently linked to brain atrophy (shrinkage) in older adults, the UK Biobank data showed that cannabis users in the same age group did not display these shrinkage patterns – and many users showed larger volumes in regions associated with memory and motor function compared to non-users.
The biological reason this might happen at all, in older brains specifically, has to do with the endocannabinoid system – a network of receptors throughout the brain and body that regulates things like mood, appetite, and memory. Pre-clinical models suggest that cannabinoids affect the brain and cognition in an age-dependent fashion, having generally beneficial effects on older animals and deleterious effects on younger ones. Laboratory research adds another layer: while the harmful effects of cannabis on the developing adolescent brain are well acknowledged, long-term implications of cannabis use on brains of older adults remain less understood – which is precisely why this wave of research matters.
There’s also a neuroprotective angle being explored. A 2022 paper in Frontiers in Pharmacology found that cannabidiol (CBD, one of the main active compounds in cannabis) “has anti-inflammatory properties that may shield neurons from long-term damage caused by chronic inflammation.” Chronic neuroinflammation is a key driver of age-related cognitive decline and conditions like Alzheimer’s disease. Researchers at the University of Colorado Anschutz see this as a plausible mechanism worth pursuing, though most of the evidence remains at the laboratory stage and has not yet been confirmed in large human trials.
Older Adults Are Already Voting With Their Feet
Whatever scientists are still working out, older Americans aren’t waiting for a final verdict. Cannabis use has increased among older adults, yet the neurocognitive effects in this demographic remain unclear, and the numbers keep rising. According to Harvard Health, 7% of adults 65 and older used cannabis in the past month in 2023, up from 4.8% in 2021 – a jump of nearly 46%. Among those in the 50-80 age bracket, the shift is even more striking: one in five people in that range used cannabis at least once in the past year, up from one in eight just four years prior.
Part of what’s driving this is a generational shift. Adults who came of age in the 1960s and 70s aren’t strangers to cannabis – they’re returning to it, often with specific health goals. Pain management, sleep, and anxiety relief are the most commonly cited reasons.
Despite rising use, the communication gap with healthcare providers remains wide. Just 56% of older Americans using marijuana have discussed their usage with a healthcare provider – meaning nearly half are navigating potential drug interactions and dosing questions without medical guidance. That’s a problem, because cannabis interacts with anticoagulants (blood thinners), sedatives, and several common heart medications in ways that aren’t trivial.
The Working Memory Problem and Heavy Use
The Colorado study’s findings were not uniformly positive. Cognitive benefits appeared most clearly in moderate lifetime users, not in heavy users. Separate research from the University of Colorado Anschutz, described as the largest study ever done on cannabis and brain function, found that 63% of heavy lifetime cannabis users exhibited reduced brain activity during a working memory task. Working memory is the cognitive system that holds and manipulates information in real time – it’s what you use to follow a conversation, do mental arithmetic, or remember why you walked into a room.
The research also found, importantly, that cognitive impairments from cannabis use typically diminish after a period of abstinence – suggesting that at least some of the functional effects are reversible rather than permanent. That’s relevant for anyone reassessing their use pattern. The practical implication: heavy, chronic use appears to undermine the cognitive advantages observed in moderate users.
What the Research Says About Young Brains – and Why It Matters
The age-dependence of cannabis effects cuts sharply in the opposite direction for younger users. Pre-clinical models suggest cannabinoids have generally deleterious effects on younger brains, and the human data support this. A 2026 study published in the journal Neuropsychopharmacology found that adolescent cannabis use was associated with a significantly increased risk of incident psychotic and bipolar disorders, with the risk roughly doubling compared to non-users. According to data from the DEA’s Get Smart About Drugs program, teens who use cannabis are also more likely to develop depression and anxiety disorders.
Adolescent cognitive development takes a hit, too. Researchers at the UC San Diego School of Medicine, analyzing data from more than 11,000 participants in the ABCD (Adolescent Brain Cognitive Development) Study – the largest long-term study of brain development in U.S. youth – found that teens who begin using cannabis show slower improvements in memory, attention, and processing speed compared to non-using peers. These aren’t transient effects: the ABCD Study tracks children from early adolescence into adulthood, and the divergence in cognitive trajectories is measurable over time.
The same Guha-led 2026 research that found cognitive advantages in older users stated explicitly in the Journal of Studies on Alcohol and Drugs that cannabis may influence brain health differently across the lifespan, potentially offering protective effects in older age while posing real risks during development. That’s not a contradiction – it reflects how profoundly the brain changes between age 15 and age 55, and how differently the endocannabinoid system functions at each stage.
The Heart Risk Is Real, Especially Before 55
The brain findings don’t eliminate the cardiovascular equation. A 2024 analysis of over 434,000 U.S. adults, published directly in the Journal of the American Heart Association, found that any cannabis use was independently associated with higher rates of heart attack and stroke, with risks rising the more frequently it was used. Younger adults – defined as men under 55 and women under 65 – who used marijuana had a 36% higher risk of coronary heart disease, heart attack, and stroke, regardless of whether they also used traditional tobacco products.
Any marijuana use was linked to a higher risk for heart attacks and strokes, but people who used it most frequently had the highest odds. Adults who used marijuana daily had 25% higher odds of having a heart attack and 42% higher odds of stroke than people who didn’t use it at all.
There is some nuance, however, once established heart disease is already present. A 2025 study reported by Medical Xpress found that smoking or consuming cannabis does not appear to raise the risk of heart attacks or strokes among older veterans who already have coronary artery disease. That doesn’t give cannabis a clean bill of cardiovascular health – it suggests the risk profile may differ between people developing heart disease and those who already have it. Either way, anyone with a cardiac history should have a direct conversation with their doctor before using cannabis regularly.
Physical Risks That Get Less Attention
Two physical risks associated with older cannabis users rarely make headlines but deserve mention. A 2022 study in the journal Drug and Alcohol Dependence found that older chronic cannabis users have a higher fall risk and walking impairments compared to non-users – a finding that matters considerably when falls are already the leading cause of injury-related death in adults over 65 in the U.S. And a 2019 study published in Drugs and Aging found that among older adults using cannabis, 33.6% reported adverse events, with dizziness and fatigue being the most common complaints – both of which compound fall risk directly.
One concern that the data consistently fails to support is the “amotivational syndrome” idea – the cultural stereotype that regular cannabis use kills drive and ambition. A 2025 study in Social Psychological and Personality Science found that “chronic users are more motivated when motivation is assessed via objective behavioral tasks” – and showed no evidence linking cannabis use to a loss of goal-directed behavior.
Read More: Psychiatrist Weighs In: Alcohol vs. Cannabis Risks After New Side Effect Emerges
What to Do With This Information
The 2026 University of Colorado study, published in the Journal of Studies on Alcohol and Drugs, doesn’t recommend cannabis for brain health, and neither does any major health body. What it does suggest is that the blanket narrative that cannabis harms the aging brain is an oversimplification – and that for adults past middle age, the picture is meaningfully different from what research in younger populations has historically shown.
If you’re over 40 and considering cannabis, moderate and infrequent use appears to sit in a very different risk category than heavy, daily use. The cognitive downsides found in heavy users – particularly the working memory reduction – point toward a dose-response relationship where more is not better. Smoking remains the highest-risk delivery method for cardiovascular health; edibles and vaporizers carry different (though not absent) risk profiles. If you’re under 55 with no existing heart disease, the cardiovascular data warrants real caution. And regardless of age, the 44% of older cannabis users who haven’t yet spoken to their doctor about it should put that conversation on the agenda – not because cannabis is uniquely dangerous, but because drug interactions and dosing in older adults are genuinely complex, and flying blind on that is unnecessary.
Disclaimer: This information is not intended to be a substitute for professional medical advice, diagnosis, or treatment and is for information only. Always seek the advice of your physician or another qualified health provider with any questions about your medical condition and/or current medication. Do not disregard professional medical advice or delay seeking advice or treatment because of something you have read here.
AI Disclaimer: This article was created with the assistance of AI tools and reviewed by a human editor.