After 40, moderate cannabis use boosts the brain

Research into the effects of cannabis on the brain has long focused on adolescents and young adults, often highlighting risks to memory or attention.

A new study has focused on a less-studied group: the middle-aged adults and seniors. Based on data from the UK Biobank, Researchers at the University of Colorado Anschutz report associations between cannabis use, greater brain volume and better cognitive performance in adults aged 40 to 77.

The results, published in early February 2026, add nuance to a debate often presented in overly simplistic terms. According to the authors, lifetime exposure to cannabis does not appear to have a uniformly detrimental effect on the aging brain and may, in certain contexts, be linked to the preservation of brain structure and function.

A large-scale study on aging, cognition and cannabis

The study analyzed data from 26,362 participants, with an average age of 55. The participants indicated the number of times they had used cannabis in their lifetime, which enabled the researchers to classify them into non-consumers, moderate consumers and frequent customers.

Using neuroimaging and cognitive assessments, the research team focused on brain regions with a high density of CB1 cannabinoid receptors, known to interact with compounds found in cannabis. These regions are involved in key cognitive domains such as’learning, memory, attention, processing speed and executive functions, who are generally vulnerable to age-related decline.

«Overall, the results showed that higher lifetime cannabis use in middle-aged and older adults... was generally associated with greater brain volume and better cognitive function,» said Anika Guha, PhD, clinical psychologist at CU Anschutz and lead author of the study.

Brain volume, aging and the meaning of «bigger».»

Rather than looking at overall brain size, the researchers adopted a region-by-region approach, which gave them a better understanding of how the cannabis use could be linked to specific neuronal structures. L’seahorse, a region essential to memory and strongly implicated in dementia, particularly caught their attention.

As Ms. Guha explains, «with age, we often observe a decrease in brain volume due to processes such as atrophy and neurodegeneration». In this context, a larger regional volume may reflect the maintaining brain integrity rather than abnormal growth.

The study revealed that most of the regions with greater volume in cannabis users were also associated with greater improved cognitive performance, This suggests a functional relevance to the structural differences observed.

Moderation, gender differences and a complex picture

One of the clearest patterns to emerge was the role of a moderate consumption. In many areas, participants in the moderate consumer category achieved the best results, both in terms of brain volume and cognitive tests. In a small number of cases, such as visual memory, the heavy-drinkers performed best, suggesting the need for a more sophisticated approach. dose-dependent effects.

The researchers also explored the gender differences, noting that men and women consume cannabis differently and may have distinct cannabis dynamics. endocannabinoid system. Although no simple pattern emerged, significant interactions between several brain regions suggest that gender is an important variable for future research.

It is important to note that the results were not uniformly positive. Higher cannabis consumption was associated with lower volume in the posterior cingulum, a region of the brain involved in memory and emotions. However, existing research offers conflicting interpretations of what a reduction in volume in this area might mean, amplifying the study's central conclusion: the effects of cannabis on the brain are not neither purely beneficial nor purely harmful.

Implications for public health and policy

Guha warns against over-interpreting the results. The study did not have detailed information on product types, potency, THC vs. CBD content or reasons for consumption, factors that are particularly relevant given the evolution of cannabis products over time.

«I think the main conclusion to draw is that the situation is nuanced. It's not a question of saying that cannabis is entirely good or entirely bad,» she said.

Cannabis being increasingly used by the elderly for problems such as sleep disorders and chronic pain, These results demonstrate the need for more targeted research. With an aging population and evolving cannabis markets, understanding the long-term effects on the brain is becoming a public health priority, one that will require in-depth, evidence-based discussion rather than simple headlines.