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Updated: Sep 16, 2025
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Brain Morphology of Cannabis Users With or Without Psychosis: A Pilot MRI Study
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Cannabis and Cognitive Function in Multiple Sclerosis: Findings From a Large Consecutive Clinical Sample.
Anne Kever1,2, Cecilia Meza1,3, Anthony Feinstein1,3
1Division of Neurology, Department of Medicine, Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.
European Journal of Neurology
|July 5, 2025
Summary
Recreational cannabis use in persons with MS (pwMS) is linked to poorer cognitive function, specifically in processing speed and working memory. This highlights a potential risk factor for cognitive decline in MS patients.
Area of Science:
- Neurology
- Neuroscience
- Pharmacology
Background:
- Cannabis is frequently used by persons with MS (pwMS) for symptom management.
- Prior research on cannabis's impact on cognitive function in MS has produced inconsistent findings.
Purpose of the Study:
- To investigate the association between recreational cannabis use and objective cognitive performance in a large clinical cohort of pwMS.
Main Methods:
- A cross-sectional study involving 847 pwMS who reported cannabis consumption.
- Cognitive function was assessed using the Minimal Assessment of Cognitive Function in MS (MACFIMS) battery.
- MANOVA and multiple linear regressions were employed to compare cognitive performance between users and nonusers and to identify independent predictors.
Main Results:
- Cannabis use significantly impacted cognitive performance (p=0.030), with users showing poorer performance on the SDMT (p=0.014).
- Regression analyses, controlling for covariates, indicated that cannabis use independently predicted poorer performance on the SDMT, PASAT-3, and PASAT-2 (all p<0.001).
Conclusions:
- Cannabis use is associated with diminished processing speed and working memory in pwMS, suggesting it as a potential risk factor for cognitive impairment.
- This association is concerning given the increasing legalization and potency of cannabis worldwide.
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