Cannabis, Cocaine, and Amphetamines All Linked to Higher Stroke Risk in Major Analysis

Meta-analysis of 32 studies (>100 million participants) found cannabis associated with 37% higher stroke risk (OR 1.37), cocaine with 96% higher risk (OR 1.96), and amphetamines with 122% higher risk (OR 2.22). Mendelian randomization confirmed cannabis use disorder was causally associated with any stroke (OR 1.11) and large artery stroke (OR 1.35).

Systematic review and meta-analysis of 32 observational studies, plus two-sample Mendelian randomization using genome-wide association data to test causal relationships between drug exposures and stroke subtypes.

The Mendelian randomization component is crucial because it uses genetic variation to approximate a natural experiment, providing stronger evidence for causation than observational studies alone. Finding that cannabis use disorder is genetically linked to large artery stroke is a significant public health signal.

As cannabis use increases globally, understanding its cardiovascular risks becomes more pressing. This study provides the strongest evidence to date that cannabis use disorder is causally linked to stroke, particularly large artery stroke, which is among the most disabling subtypes.

Observational meta-analysis showed heterogeneity and small-study effects for cannabis. Mendelian randomization assumes certain conditions (no pleiotropy, relevant instruments) that may not be perfectly met. Cannabis use disorder genes may also influence other behaviors.