Incidence of strokes has increased these last 20 years in young population. This rise could be linked to alcohol, tobacco or drug use like cannabis. Cannabis has previously been descripted as a potential factor of reversible vasoconstriction. The main objective is to show that an exhaustive assessment of a stroke facing a young person frequently lead to a diagnostic of reversible vasoconstriction due to cannabis use. Evaluation will focus on prevalence of strokes secondary to a reversible vasoconstriction attributable to cannabis in young subjects.

There's a real public healthcare interest in terms of primary and secondary prevention to evaluate the role of cannabis as a risk factor of stroke in young population.

Inclusion Criteria:

• Subject between 18 and 45 years old
• Stroke confirmed by medical imaging
• Written informed consent (subject, nearby or emergency procedure)
• Subject affiliate to a local healthcare insurance office
• For female of childbearing potential, an adequate contraceptive measur

Exclusion Criteria:

• Subject with psychiatric disorder, unable to understand the study or cooperate
• Subject under guardianship or forfeiture of liberty
• Pregnant or breastfeeding woman
• Subject in period of exclusion due to another study or still in follow-up of an interventional study