Researchers study differences in ischemic stroke in marijuana users

Stroke in marijuana users more often caused by narrowing of arteries in skull

Contact: Beth Casteel,, 202-375-6275

WASHINGTON (Oct 26, 2015) -

A new study found strokes in young adults who use marijuana are more likely to be caused by stenosis, narrowing of the arteries, in the skull than strokes in non-users.

Previous studies have found an association between marijuana use and stroke, but the new study published today as a research letter in the Nov. 3 issue of the Journal of the American College of Cardiology is the first to explore differences in stroke in marijuana users and non-users, an approach that can help researchers begin to identify possible mechanisms for stroke in users.

The researchers from The University Hospital of Strasbourg in Strasbourg, France, looked at all patients under age 45 admitted with ischemic stroke from 2005 to 2014, creating a study cohort of 334 patients, including 58 who were marijuana users. Ischemic stroke is caused by a blockage that interrupts or reduces blood flow to the brain as opposed to hemorrhagic stroke, which occurs when a blood vessel in the brain leaks or ruptures.

In marijuana users in the study, ischemic stroke was more likely to be caused by intracranial arterial stenosis, a condition where there is narrowing the arteries inside the skull caused by a buildup of plaque.  Intracranial arterial stenosis was found in 45 percent of the marijuana users in the study compared to 14 percent of the non-users.

Marijuana users in the study were younger, more likely to be male, more likely to smoke tobacco, and more likely to have other lifestyle risk factors than non-users in the study.

Cardio embolism, a blood clot formed elsewhere in the body that moves to the brain, was most common cause of ischemic stroke in non-marijuana users in the study. Investigators found 29 percent of strokes in non-users were caused by cardio embolism compared to only 14 percent in the marijuana users.

“Fighting stroke must remain a priority, including in young adults,” said the authors, led by Valerie Wolff, M.D., PhD. “The first step may be to inform the public regarding the potential occurrence of stroke associated with cannabis and other lifestyle risk factors.”

JACC Editor in Chief Valentin Fuster, M.D., PhD., said “The effects of cannabis have been considered benign for a long time; however, evidence continues to build about the relationship of its use with stroke.”

The American College of Cardiology is a 49,000-member medical society that is the professional home for the entire cardiovascular care team. The mission of the College is to transform cardiovascular care and to improve heart health. The ACC leads in the formation of health policy, standards and guidelines. The College operates national registries to measure and improve care, provides professional medical education, disseminates cardiovascular research and bestows credentials upon cardiovascular specialists who meet stringent qualifications. For more information, visit

The Journal of the American College of Cardiology, which publishes peer-reviewed research on all aspects of cardiovascular disease, is the most widely read cardiovascular journal worldwide. JACC is ranked No. 1 among cardiovascular journals worldwide for its scientific impact. The latest research and clinical practice updates in cardiology are at your fingertips with the JACC Journals app for iPhone/iPad and Android.


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