Recreational marijuana legalization in the United States has been linked to a faster rise in hospitalizations for certain cardiovascular conditions, according to a recent study analyzing more than 50 million hospital discharge records. The research, published on October 22 in BMJ Open, focused on trends in the Western United States, finding that admissions for atrial fibrillation, heart failure, and heart attacks increased more rapidly following the legalization of recreational cannabis sales compared to areas without such laws.
The study examined hospital records from 2012 through 2018 across 13 Western states: Alaska, Arizona, California, Colorado, Hawaii, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming. Researchers compared hospitalization trends before and after the introduction of recreational cannabis sales with trends in regions where the substance remained illegal for recreational use.
After adjusting for other variables, the analysis showed that hospitalization rates rose approximately 2% faster annually for atrial fibrillation, nearly 4% faster for heart failure, and just over 3% faster for heart attacks in states that implemented recreational marijuana legalization. While other cardiovascular conditions such as ischemic stroke, venous thromboembolism (blood clots), and ventricular tachycardia (rapid heartbeat) exhibited upward trends, these increases were not statistically significant.
The data was drawn from the National Inpatient Sample, a comprehensive database covering about 97% of the U.S. population. Notably, before legalization, the study found that hospitalization rates for these conditions were lower in the 13 Western states than in regions without recreational marijuana laws.
Researchers suggest several physiological mechanisms through which cannabis might impact cardiovascular health, including alterations in heart rate, blood pressure, and blood clotting functions. They also noted that legalization has coincided with increased cannabis use, including among older adults who are inherently at greater risk for cardiovascular issues.
Despite these associations, the authors emphasized that the study does not establish a direct causal link between recreational marijuana legalization and increased cardiovascular hospitalizations. Limitations include the inability to confirm whether hospitalized individuals used cannabis prior to their cardiac events, lack of information on consumption methods, and the potential influence of illegal cannabis use.
“While an observational study cannot prove causality, our findings point to potential adverse effects of recreation legalization on population health,” the researchers wrote. They called for ongoing research and surveillance of cardiovascular outcomes as recreational cannabis laws continue to expand across the United States.
As of June 2025, recreational cannabis was legal in 24 states, with medical cannabis permitted in 41 states, underscoring the importance of further studies to understand the public health implications of expanding cannabis access.