Smoking Cannabis Linked To Larger Brain Volume And Better Cognitive Function Later In Life

 Smoking Cannabis Linked To Larger Brain Volume And Better Cognitive Function Later In Life

Benjamin Taub

IFL Science

Tuesday 10 Feb 2026

Moderate use appears to protect the hippocampus from shrinking.



People who have used cannabis at any stage during their lives display larger volumes in brain regions linked to memory, learning, and executive function by the time they reach middle age, new research shows. As with all studies linking pot use with cognitive outcomes, however, these findings come with several caveats, as there are numerous variables that complicate the long-term health effects of cannabis use.

Nonetheless, the results of this latest study are noteworthy, particularly given the strength of the positive signal detected by the researchers. Using data from over 25,000 people between the ages of 40 and 77, they found that moderate lifetime cannabis use correlates with size increases in the hippocampus, amygdala, caudate, and putamen.

Given that these brain regions are linked to key attributes like emotion, motor control, and memory, the researchers decided to investigate how cannabis use impacts cognition from mid-life onwards. Examining data from 16,728 individuals, they found that, once again, moderate use was linked to better performance in tasks that engage learning, processing speed, and short-term memory.

“I was a little surprised that every cognitive measure that demonstrated a significant effect showed better performance among cannabis users,” said study author Anika Guha in a statement. “It goes against your default assumptions, because I think a lot of research out there has shown cannabis is associated with worse cognitive function, at least acutely.”

The researchers therefore suggest that while using pot may pose risks to adolescents, these harms do not appear to persist later in life. Instead, cannabis may actually protect the brain against age-related atrophy and neurodegeneration, both of which are strongly linked to cognitive decline and dementia.

At this stage, it’s unclear how the drug exerts these positive effects, although it’s noteworthy that all of the brain regions examined in this study contain high concentrations of CB1 receptors, which represent the primary binding site for cannabinoids like tetrahydrocannabinol (THC). The authors therefore speculate that the activation of this receptor may somehow fend off brain shrinkage by modulating inflammation, immune function, or neurodegeneration.

Moreover, many of these regions are particularly prone to atrophy later in life, with loss of volume in the hippocampus thought to play a major role in dementia. As such, the researchers tentatively suggest that cannabis might help to prevent certain types of cognitive decline.

Overall, the correlation between cannabis use and both enhanced brain volume and improved cognition was strongest in people who had consumed the drug moderately during their lives. Amazingly, positive effects were even seen in those who hadn’t used pot for several decades prior to assessment.

Despite these findings, the study authors point out that there are still a lot of unknowns. For instance, cannabinoid use appears to affect male and female brains differently, and the reasons for this are not entirely clear.

Additionally, the data fails to capture details of the type or strength of cannabis that people used. The researchers are therefore unable to provide any insight into how different cannabinoids – such as THC, cannabidiol (CBD), or cannabigerol (CBG) – might be involved in mediating the harms and benefits of using pot.

Overall, then, the picture is far from straightforward, and the study authors conclude that “cannabis may influence brain health differently across the lifespan, potentially offering protective effects in older age while posing risks earlier in development.”

The study is published in the Journal of Studies on Alcohol and Drugs.

https://www.iflscience.com/smoking-cannabis-linked-to-larger-brain-volume-and-better-cognitive-function-later-in-life-82516