by: SC Labs
Summary: A study spanning 44 years and involving over 5,000 men challenges long-held beliefs about cannabis and cognition. Researchers found that cannabis users experienced slightly less cognitive decline from early adulthood to late midlife compared to nonusers.
Neither the age of cannabis initiation nor the frequency of use showed a significant impact on cognitive decline. These findings suggest that long-term cannabis use might not impair—and could even modestly benefit—cognitive aging, although further research is needed to confirm the results.
Key Facts:
- Cognitive Decline: Cannabis users experienced 1.3 IQ points less decline over 44 years compared to nonusers.
- Initiation Age: Starting cannabis before age 18 had no significant effect on long-term cognitive decline.
- Frequency of Use: Regular cannabis use (≥2 times per week) was not associated with greater cognitive decline.
Cannabis, often maligned for its short-term cognitive effects, may not have the long-term impact on mental sharpness once thought.
A groundbreaking Danish study tracking over 5,000 men for 44 years found that cannabis users experienced slightly less cognitive decline from early adulthood to late midlife compared to nonusers.
Despite cannabis being a Schedule I drug with a reputation for harm, this research suggests its effects on aging brains might be more nuanced.
The study examined cognitive changes using intelligence test scores taken in early adulthood and again decades later.
Cannabis users showed a modest advantage in maintaining IQ levels over time, even when controlling for lifestyle factors such as education and substance use.
Moreover, neither the age at which cannabis use began nor frequent use significantly accelerated cognitive decline.
These findings challenge previous assumptions that cannabis usage contributes to steeper cognitive decline.
Instead, they hint at a complex relationship where factors like baseline IQ, education, and lifestyle may play a larger role.
While the observed differences were minor and might lack clinical significance, the research opens the door for further exploration of cannabis’ long-term effects on cognition.
Funding: This work was supported by a number of grants. The DanACo cohort was established by pooling the two follow-up studies, the LiKO-15 and DiaKO-19 studies.
The establishment of the LiKO-15 study was part of the Phenotypes in Alcohol Use Disorders project, which was supported by Innovation Fund Denmark, Health and Clinical Research (Grant Number 603-00520B) and was further supported by the Center for Healthy Aging, University of Copenhagen, and a PhD scholarship grant to MG from the Faculty of Health and Medical Sciences, University of Copenhagen.
The establishment of the DiaKO-19 cohort was supported by grants from Independent Research Fund Denmark (Grant Number: 8020-00094B), Svend Andersen foundation, and Doctor Sofus Carl Emil Friis and wife Olga Doris Friis’s foundation.
Further support for ongoing research using the LiKO-15 and DiaKO-19 cohorts has been granted by the Lundbeck foundation (Grant Number: R380-2021-1433), Helsefonden (Grant Number: 22-B-0196), and by the internal research funds of Bispebjerg and Frederiksberg hospitals.
The funding bodies had no role in the design of the studies, nor in the collection, analysis, and interpretation of data and writing of the manuscript.
Source by: SC Labs
