“The association between marijuana use and ischemic stroke (IS) risk remains controversial. The goal of this study was to determine the effect of marijuana use on the risk of young-onset IS among Caucasians and African-Americans.

Having a history of marijuana/hashish use was not associated with IS in the overall sample or any gender-/ethnic-specific subgroup. Our data does not demonstrate a risk of ischemic stroke as associated with marijuana use.”

http://n.neurology.org/content/82/10_Supplement/S55.003

“No Link Between Marijuana Use and Stroke Risk. There was no evidence that marijuana use was associated with an increased risk of ischemic stroke in adolescents and young adults.”  https://www.medpagetoday.com/meetingcoverage/aan/45577