Recreational Cannabis Legalization Linked to Faster Rise in Heart Attack and Arrhythmia Admissions

The data behind this study come from hospital discharge records: 50,042,564 of them, covering the years 2012 through 2018, drawn from the National Inpatient Sample. The states that take part in that sample account for roughly 97% of the US population. A team of researchers used the records to ask whether the legalization of recreational cannabis shows up in the number of people admitted to hospital with heart problems. Their findings were published in the open access journal BMJ Open.

They concentrated on the Western region of the country: Alaska, Arizona, California, Colorado, Hawaii, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington and Wyoming. The region began legalizing recreational cannabis in January 2014, nearly five years before other regions did. By 2018, more than 98% of people in the West lived in a state with legal cannabis sales or next to one. As of June 2025, the researchers note, medicinal cannabis was legal in 41 US states and recreational use in 24.

The team tracked admissions for six conditions: acute heart failure, heart attack, atrial fibrillation or flutter, ischaemic stroke, venous thromboembolism (deep vein blood clots), and ventricular tachycardia. For each, they set a baseline using admission rates per 100,000 people in the two years before the first legal recreational sale. They then compared how rates moved before and after legalization in the West against regions that had not enacted such laws.

Before legalization, in 2012 and 2013, the Western region had lower discharge rates for these diagnoses than regions without the policy. After legalization, its rates climbed faster. After adjusting for factors that could influence the result, the estimated change for each year of legal sales was statistically significant for three conditions: atrial fibrillation, just over 2% higher; heart attack, just over 3% higher; and heart failure, nearly 4% higher. Rates for the other conditions were also higher but did not reach statistical significance.

The patients differed between regions too. Over the study period, those admitted in the West were younger on average (51 against 55), more often lived in higher-income ZIP codes (26% against 19%), and less often identified as White.

The researchers explain that cannabis use can affect cardiovascular health through several physiological mechanisms. They add that legalization has been linked to wider use of cannabis products, particularly among older people, who already face a higher risk of cardiovascular problems.

The study is observational, so it cannot establish cause and effect, and the authors list its limits. They could not separate individual states, could not look at how cannabis was consumed (smoked or not), and could not account for trends in illegal use. They also say it is the first study to examine legalization's association with cardiovascular hospitalizations; earlier work looked at psychiatric conditions, substance use, emergency visits and traffic accidents.

The authors write that while an observational study cannot prove causality, their findings point to potential adverse effects of recreational legalization on population health. They say the results support a cautious approach to legalization laws worldwide, accompanied by data collection on cardiovascular outcomes. That call for routine tracking is what to watch next.