(HealthDay News) — Cannabis seems to be linked to cerebrovascular events, according to research published online Feb. 19 in Stroke.

Daniel G. Hackam, M.D., Ph.D., from Western University in London, Canada, reviewed case reports on cannabis and cerebrovascular events. Four criteria for causality were addressed: temporality, stroke work-up adequacy, the impact of rechallenge, and concomitant risk factors for cerebrovascular events.

Hackam identified 34 case reports on 64 patients. A temporal relationship between cannabis exposure and the index event was exhibited in 81 percent of cases. The evaluation was sufficiently comprehensive to exclude other sources for stroke in 70 percent of cases. Twenty-two percent of patients had another stroke after subsequent cannabis re-exposure. Concomitant risk factors were identified in 50 percent of patients, most commonly tobacco and alcohol consumption (34 and 11 percent, respectively).

“Overall, however, it seems clear that physiological, clinical, and epidemiological data converge on an increased stroke risk from cannabis exposure,” Hackam writes. “Heightened clinician awareness of this association, particularly in the treatment of young adults, is necessary for preventing recurrent events from future re-exposure to cannabis.”

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