Meta-Analysis Finds Cannabis Users Have Twice the Risk of Ischemic Stroke | Research

The takeaway

A systematic review and meta-analysis of seven studies found cannabis use was associated with a two-fold increased risk of ischemic stroke (pooled OR 2.05), particularly among young adults.

Neurologists and stroke specialists; young adults using cannabis regularly.

Pooled OR = 2.05 for ischemic stroke risk among cannabis users

What the researchers found

Pooled analysis of seven studies revealed a statistically significant association between cannabis use and ischemic stroke risk (pooled OR = 2.05, 95% CI: 1.46-2.87, p < 0.001). Moderate heterogeneity was present (I-squared = 68.9%, p = .007).

Why it matters

Ischemic stroke among young adults is increasing globally, paralleling rising cannabis use. This meta-analysis provides the strongest pooled evidence to date that cannabis use approximately doubles stroke risk, a finding with particular relevance as legalization expands and cannabis is increasingly perceived as low-risk.

The numbers in context

821 initial records screened, 7 studies included (published 2007-2023). Pooled OR = 2.05 (95% CI: 1.46-2.87). Heterogeneity: I-squared = 68.9%. Studies included case-control, cohort, and cross-sectional designs.

How the study worked

Systematic review and meta-analysis following PRISMA guidelines. Searched PubMed, Web of Science, Scopus, Embase, and Google Scholar through March 2025. Seven studies (2007-2023) including case-control, cohort, and cross-sectional designs met inclusion criteria. Random-effects model used for pooling. Quality assessed with JBI checklist.

What this study cannot tell us

Only seven studies met inclusion criteria, reflecting the limited evidence base. Moderate heterogeneity suggests variability across studies. Most studies relied on self-reported cannabis use and could not control for dose, frequency, or method of consumption. Observational designs cannot prove causation.

How to read the evidence

Moderate: systematic review with meta-analysis and significant pooled results, but limited by small number of included studies, moderate heterogeneity, and observational designs.

When this study was published

2025 meta-analysis including studies from 2007-2023.

The bigger picture

Cannabis can trigger vasospasm, affect cerebral blood flow, and promote prothrombotic states through various mechanisms. The doubling of stroke risk is particularly concerning for young adults, who may not be screened for stroke risk factors and who disproportionately use cannabis.

Questions still open

Does stroke risk vary by cannabis consumption method (smoking vs edibles vs vaping)? Is the risk dose-dependent, with heavier users at greater risk? Do specific cannabinoid profiles affect stroke risk differently?

Common questions

How might cannabis cause strokes?

Several mechanisms have been proposed: cannabis can cause vasospasm (sudden narrowing of blood vessels), alter cerebral blood flow, promote blood clotting, and trigger cardiac arrhythmias. Smoking cannabis adds combustion-related vascular damage similar to tobacco.

Is this risk high compared to other stroke risk factors?

A two-fold increase is clinically significant and comparable to some established stroke risk factors. However, the absolute risk of stroke in young adults is low, so a doubling still represents a relatively small absolute risk increase for most individuals.

Read the original research

Cannabis use in different ethnicity/race populations and risk of ischemic stroke: A systematic review and meta-analysis.

Journal of ethnicity in substance abuse, 1-19

View on PubMed ↗Publisher’s paper ↗

Citation

Abdullah, Farah Thamer; Al-Dulaimi, Abdulla A; Vaghela, Krunal; H, Malathi; Prasad, K D V; Mohammed, Jaafaru Sani; Gupta, Harshit; Sahoo, Samir; Hulail, Hanen Mahmod; Kadhem, Mundhr. (2025). Cannabis use in different ethnicity/race populations and risk of ischemic stroke: A systematic review and meta-analysis.. Journal of ethnicity in substance abuse, 1-19. https://doi.org/10.1080/15332640.2025.2505059