Recreational marijuana legalization in the United States has been linked to faster increases in hospitalizations for three cardiovascular conditions, according to a new study examining more than 50 million hospital discharge records.
The study, published Oct. 22 in the journal BMJ Open, found that hospital admission rates for atrial fibrillation, heart failure and heart attacks rose faster in the Western United States after recreational cannabis sales became legal than in regions without similar laws.
Researchers analyzed hospital records from 2012 through 2018 in 13 Western states: Alaska, Arizona, California, Colorado, Hawaii, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington and Wyoming. They compared hospitalization trends before and after recreational marijuana sales became legal in the region with trends in areas without similar laws.
The findings suggest a possible association between recreational cannabis legalization and cardiovascular health, but researchers cautioned that the study cannot establish that legalization caused the increases.
Which Heart Conditions Were Potentially Linked to Legalization?
Researchers examined hospital admissions for six cardiovascular conditions: atrial fibrillation or flutter, acute heart failure, heart attacks, ischemic stroke, venous thromboembolism (blood clots) and ventricular tachycardia (rapid heartbeat).
After accounting for other factors that could affect the results, researchers found that hospital admissions increased more quickly each year in the 13 states after recreational marijuana sales became legal. Compared with regions without similar laws, hospitalization rates rose just over 2% faster for atrial fibrillation, nearly 4% faster for heart failure and just over 3% faster for heart attacks.
Hospitalization rates for stroke, blood clots and ventricular tachycardia also trended higher, but the differences were not statistically significant.
The analysis included over 50 million hospital discharge records from the National Inpatient Sample, a database covering participating states that represent approximately 97% of the U.S. population.
Before recreational marijuana sales became legal, hospitalization rates for the conditions studied were lower in the 13 Western states than in regions without similar laws.
How Could Cannabis Affect Heart Health?
Cannabis may affect cardiovascular health through several physiological mechanisms, the researchers said. These include changes in heart rate and blood pressure, as well as potential effects on blood clotting.
Legalization has also been associated with more widespread cannabis use, including among older adults, who already face increased cardiovascular risks, according to the study.
As of June 2025, recreational cannabis was legal in 24 states, while medical cannabis was legal in 41 states, the researchers noted.
Study Has Limitations
The study cannot prove that recreational marijuana legalization caused hospitalizations to increase. Researchers could not determine whether individual patients used cannabis before developing heart problems, distinguish between methods of cannabis consumption or account for changes in illegal cannabis use.
“While an observational study cannot prove causality, our findings point to potential adverse effects of recreation legalisation on population health,” the researchers wrote.
They said further research and continued monitoring of cardiovascular health are needed as more places legalize recreational cannabis.
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