The most comprehensive analysis yet on recreational drug use and stroke risk has identified three substances of concern – one of which may nearly triple the risk of a blood vessel bursting in the brain. Researchers at the University of Cambridge in the UK found that participants in a series of studies who recreationally used amphetamines, cocaine, or cannabis were more likely to suffer a stroke than non-users. Those who used amphetamines faced the greatest risks, but cocaine wasn't far behind.