Recreational drug use — including cannabis — significantly increases the risk of stroke, according to the largest-ever meta-analysis on the topic, which pooled data from more than 100 million people across 32 studies.
Researchers at the University of Cambridge found that cocaine was associated with a 96% increase in stroke risk, amphetamines with a 122% increase, and cannabis with a 37% increase. The results, published in the International Journal of Stroke, held even after the team used Mendelian randomization — a technique that leverages genetic variants to test for causal relationships — to rule out confounding lifestyle factors.
The risk was especially stark for younger users. Among people under 55, amphetamine use was associated with a 174% increase in stroke risk — nearly triple — while cocaine doubled it at 97%. Cannabis showed a smaller but still notable 14% increase in this age group.
"This is the most comprehensive analysis ever conducted on recreational drug use and stroke risk and provides compelling evidence that drugs like cocaine, amphetamines, and cannabis are causal risk factors for stroke," said Dr. Megan Ritson of the Cambridge Stroke Research Group.
The biological mechanisms likely involve sudden spikes in blood pressure, blood vessel spasms and narrowing, abnormal heart rhythms, increased blood clotting (particularly with cannabis), and inflammation or vasculitis (particularly with amphetamines). All of these are established contributors to both ischemic and hemorrhagic stroke.
Problematic alcohol use was also linked to increased risk of cardioembolic stroke and large artery stroke, while alcohol addiction in general was associated with a higher overall stroke risk. Opioid use, by contrast, showed no statistically significant association with stroke.
Stroke remains the third leading cause of death and disability worldwide. The findings reinforce the importance of public health measures to reduce substance abuse as a means of also reducing stroke burden, particularly among younger populations where recreational drug use is most prevalent.
