Intracranial arterial stenosis was found to be the main etiology of stroke in cannabis users, occurring in 45% of these patients compared to just 14.5% of noncannabis users. Among non-users cardioembolism was the most frequent cause of stroke, occurring in 29.3% of patients compared to 14% of cannabis users.

Source: Vessel Blockage Common in Young Stroke Patients Who Smoke Pot | Medpage Today

YIKES.