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Chronic marijuana use linked to recurrent stroke



Hypothesis-generating research

The study did not investigate the possible mechanisms by which marijuana use might increase stroke risk, but Dr. Jain speculated that these could include factors such as impaired blood vessel function, changes in blood supply, an increased tendency of blood clotting, impaired energy production in brain cells, and an imbalance between molecules that harm healthy tissue and the antioxidant defenses that neutralize them.

As cannabis use may pose a different risk for a new stroke, as opposed a previous stroke, Dr. Jain said it would be interesting to study the amount of “residual function deficit” experienced with the first stroke.

The new study represents “foundational research” upon which other research teams can build, said Dr. Jain. “Our study is hypothesis-generating research for a future prospective randomized controlled trial.”

A limitation of the study is that it did not consider the effect of various doses, duration, and forms of cannabis abuse, or use of medicinal cannabis or other drugs.

Robert L. Page II, PharmD, professor, departments of clinical pharmacy and physical medicine/rehabilitation, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, provided a comment on this new research.

A cannabis use disorder diagnosis provides “specific criteria” with regard to chronicity of use and reflects “more of a physical and psychological dependence upon cannabis,” said Dr. Page, who chaired the writing group for the AHA 2020 cannabis and cardiovascular disease scientific statement.

He explained what sets people with cannabis use disorder apart from “run-of-the-mill” recreational cannabis users is that “these are individuals who use a cannabis product, whether it’s smoking it, vaping it, or consuming it via an edible, and are using it on a regular basis, in a chronic fashion.”

The study received no outside funding. The authors report no relevant disclosures.

A version of this article first appeared on


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