| Title: | Lifetime Cannabis Use Is Associated with Brain Volume and Cognitive Function in Middle-Aged and Older Adults |
| Authors: | Anika Guha , PhD1, Zening Fu , PhD, Vince Calhoun , PhD, and Kent E. Hutchison , PhD |
| Year: | 2026 |
| Journal: | Journal of Studies on Alcohol and Drugs |
A newly published cross-sectional study examining associations between lifetime cannabis use, brain volume, and cognitive function in middle-aged and older adults reported unexpected results.
The cross-sectional analysis included 25,809 participants with MRI data and 16,728 with cognitive assessments (ages 40–70). Cannabis exposure was based on self-reported lifetime use and categorized as none, moderate (1–100 lifetime uses), or high (>100 uses). Researchers focused on brain regions rich in CB1 receptors, including the hippocampus, amygdala, caudate, and putamen, and evaluated performance across multiple cognitive domains.
Greater lifetime cannabis use was associated with larger regional brain volumes in several CB1-dense areas, as well as better performance on tasks assessing learning, processing speed, short-term memory, and task switching. Individuals reporting moderate use consistently showed more favorable outcomes compared with non-users. Interestingly, participants whose cannabis exposure was limited to adolescence also demonstrated larger brain volumes and better cognitive performance later in life. Sex-specific effects were observed, suggesting differential neurobiological responses to cannabis between men and women.
Importantly, this was an observational, cross-sectional study relying on self-reported cannabis history, with no information on THC or CBD content, route of administration, or timing of use. As such, causality cannot be inferred. Nevertheless, these findings add to growing evidence that cannabinoids may have different effects on the brain later in life than they do during earlier developmental periods, potentially through endocannabinoid-mediated effects on inflammation, immune function, and neurodegeneration.
Overall, these results contrast with the adverse neurocognitive effects often reported in younger populations and raise important questions about age-dependent cannabis effects and brain health. Longitudinal studies with detailed exposure measures are needed to corroborate the findings, as well as clarify mechanisms and clinical relevance.
Read the full publication here:
Citation: Guha A, Fu Z, Calhoun V, Hutchison KE. Lifetime Cannabis Use Is Associated with Brain Volume and Cognitive Function in Middle-Aged and Older Adults. J Stud Alcohol Drugs. Accepted manuscript posted online December 11, 2025. doi:10.15288/jsad.25-00346.