Can Cannabis Help Protect Your Brain as You Age?

Hi, my name is Doctor Brooke Worcester, and I’m a physician researcher at Sidney Kimmel Comprehensive Cancer Center at Jefferson Health and the Chief Medical Advisor for Ethos Cannabis. Hi, I’m Emily Hagar, and I’m a clinical pharmacist. I work with older adults and in supportive oncology, and I’m also a professor in the College of Pharmacy. We are here and interested in talking about a new study that came out in early February 2026, and it looked at lifetime cannabis use, brain volumes, cognitive and memory function in older adults.

The data was collected prospectively a little bit ago from like 2006 to 2010. However, they had a really large sample size, and they interviewed people every four years or so and did MRI testing, cognitive testing, and collected a lot of variables that were banked over time. This study had over 25,000 older adults between the age of 47 and 70.

It looked at lifetime cannabis use and lumped people into groups: a never user, what they termed a moderate user — which was self-reported between 1 and 100 lifetime uses — and then frequent or regular heavy use, above 100 uses. They looked at MRIs from all of these people over time and very specifically used measurements to calculate the brain volume of specific brain areas associated with memory, cognitive functioning, executive processing, and different tasks cognitively that we do. They also looked at people’s performance on memory tests.

The takeaway was that moderate lifetime cannabis use was associated with higher brain volume and better performance on cognitive functioning and cognitive tasks — things like memory, executive functioning, processing, task completion. People in the moderate-use group did better than the group that reported no cannabis use.

What the authors question, and what I think is really interesting, is whether there is some neuroprotective or cognitive protective effect of moderate cannabis use over time in preventing some of the age-related decline we see in memory — and that decline is associated with brain volume.

They noticed that the areas that were really high in cannabis receptors, or CB1 receptors, were those that maintained volume over time. There is a bit of dispute in the literature about whether cannabis helps or hurts brain function. They even showed that people who had used cannabis in adolescence — which is typically considered the highest risk period because of neural development — still demonstrated protective effects into older adulthood.

This calls into question the long-held belief that cannabis has a negative effect on cognitive functioning or brain volume as it relates to memory and executive functioning. It’s not talking about brain development per se, but rather that stimulation of CB1 receptors over time may prevent the loss that occurs with aging compared to those who never stimulated those receptors.

Now, this is an association. We cannot say definitive causation. This was observed repeatedly in a large, well-controlled group of people, but we can’t say that if we give someone cannabis, we are guaranteed to see that outcome on an MRI scan. We can say there is a signal suggesting that cannabis may be protective against some of that loss as we age.

It’s also important to say that it doesn’t improve anything — but it might prevent loss of brain volume. Brain volume loss over time can be associated with cognitive impairment. The fact that brain volume remained stable and cognitive testing results were also stable goes hand in hand. They conducted multiple cognitive tests, not just one, and these were done serially over time, which strengthens the findings.

Another interesting nuance was differences between sex — comparing men and women. At baseline, men tend to be heavier cannabis users and use more frequently than women. Women are increasingly using cannabis for medically oriented purposes. The study suggests that one size does not fit all. There were differences seen in the brains of men and women, both in protection of volume loss and improvements in memory and cognitive function in moderate users versus non-users, but the effects were not identical.

They found that the protective effect appeared stronger in men. Females tend to be more sensitive at lower doses and showed slightly less protection with heavier use. So there are biological differences that likely matter.

One of the key limitations is that the study lacked specificity in cannabis consumption. They relied on self-reported lifetime use but didn’t capture form, dose, potency, or composition. Asking someone to quantify lifetime use over decades introduces recall limitations. They grouped people into broader categories, but the difference between 50 and 100 uses over a lifetime could matter.

As with many things, moderation appears key. The study did not suggest that more use leads to greater benefit. It suggested that moderate use may be associated with protection, but heavy use did not show incremental benefit. No specific form of cannabis was shown to be superior.

Overall, it was a well-done study that gives directionality and stimulates further questions, which is always helpful in research. It may also reduce some fear around long-term cognitive harm. Many people worry about long-term effects, and this study may alleviate some of that concern. For patients considering cannabis for medical purposes — such as pain — this information could reduce some of the barriers to use.