[Drug abuse and stroke].
ABSTRACT Today, drug abuse pervade all over the world. Drug abusers are increasing year after year also in recent Japan especially among young people. Ischemic and hemorrhagic stroke frequently occur after use of illegal drugs. We reported two cases of young stroke associated with drug misuse. Case 1 used amphetamine, cocaine, marijuana and LSD for few yaers, and developed occlusion of a middle cerebral artery. Case 2 presented aphasia shortly after marijuana smoking. His protein S activity was low. He did not have other risk factor of cerebrovascular disease. Marijuana may have accelerated stroke onset, but essential cause of stroke in this case must be protein S mutation. Medical examination for young stroke should include screening of drug abuse and searching for coagulation disorder.