UK Biobank Study Finds Past Cannabis Use Linked to Better Cognitive Performance in Older Adults | Research

The takeaway

Among 67,713 dementia-free adults aged 60+, lifetime cannabis users performed better across all five cognitive domains tested, though longer duration of use was associated with faster decline in processing speed.

gerontologists, neuropsychologists, older cannabis users, aging researchers

What the researchers found

Cross-sectionally, lifetime cannabis users (17% of sample) performed better in attention (B=0.071), executive function (B=0.047), processing speed (B=0.363), visual memory (B=0.062), and working memory (B=0.181). Current use associated with better working memory (B=0.169). Longitudinally, past use linked to less decline in executive function, but longer duration predicted steeper processing speed decline.

Why it matters

This is one of the largest studies examining cannabis and cognition in older adults. The finding that past use is associated with better cognitive performance challenges assumptions about long-term cognitive harm, though the relationship is complex.

The numbers in context

67,713 cross-sectional; 52,002 longitudinal. Mean age 67.2 years. 46.1% male. 17% lifetime cannabis users. Better performance across all 5 cognitive domains. Longitudinal: less executive function decline with past use; more processing speed decline with longer duration.

How the study worked

Cross-sectional (n=67,713) and longitudinal (n=52,002) analyses of UK Biobank participants aged 60+. Self-reported cannabis use patterns. Computerized cognitive tests for attention, executive function, processing speed, visual and working memory. Multivariable linear regression adjusted for demographics, health, and lifestyle.

What this study cannot tell us

Self-reported cannabis use subject to recall bias. UK Biobank participants are healthier and more educated than the general population (healthy volunteer bias). Cross-sectional associations cannot determine causation. Confounders like personality traits may drive both cannabis use and cognitive performance.

How to read the evidence

Very large UK Biobank sample with longitudinal data and adjusted analyses, but self-reported exposure and healthy volunteer bias limit interpretation.

When this study was published

2025 publication.

The bigger picture

The complex pattern — better cross-sectional performance but domain-specific longitudinal decline with heavy use — suggests cannabis effects on cognition are nuanced. Survivor bias and confounding (e.g., education, personality traits correlating with both cannabis use and cognitive performance) may explain some findings.

Questions still open

Are the positive cognitive associations driven by confounders rather than cannabis itself?
Does the neuroprotective potential of cannabinoids play a role in aging?

Common questions

Does cannabis use affect memory in older adults?

This UK Biobank study of 67,713 adults over 60 found lifetime cannabis users actually performed better on memory and other cognitive tests. However, longer duration of use was linked to faster decline in processing speed, suggesting a complex relationship.

Is past cannabis use harmful to the aging brain?

This large study found past cannabis use was not uniformly harmful — users performed better on cognitive tests and showed less decline in executive function over time. However, the authors caution that confounders like education and personality traits may explain the positive associations.

Read the original research

History of cannabis use and cognitive function in older adults: findings from the UK biobank.

Age and ageing, 54(11)

View on PubMed ↗Publisher’s paper ↗

Citation

Sznitman, Sharon R; Vered, Shiraz; Weinstein, Galit. (2025). History of cannabis use and cognitive function in older adults: findings from the UK biobank.. Age and ageing, 54(11). https://doi.org/10.1093/ageing/afaf319