The popular illegal drug, marijuana, may double the risk of stroke among young adults, according to findings revealed at The American Stroke Association’s International Stroke Conference 2013.
The study, carried out in New Zealand, identified that marijuana smokers were more than twice as likely than healthy adults to have suffered an ischemic stroke and transient ischemic attack. Lead investigator of the study, Alan Barber, said "This is the first case-controlled study to show a possible link to the increased risk of stroke from cannabis. Cannabis has been thought by the public to be a relatively safe, although illegal substance. This study shows this might not be the case, it may lead to stroke."
The researchers assessed urine samples of a total of 150 ischemic stroke and 10 transient ischemic attack patients, aged between 18 and 55. From the study, close to 16 per cent of the participants in the study had positive drug screens, most of whom also smoked cigarettes. The study revealed that 8.1 per cent of those who came up positive in the urine samples smoked cannabis, as there was no difference in age or stroke mechanism between those who smoked marijuana and those who did not. Previous studies identified that ischemic stroke and transient ischemic attack could develop within hours of smoking marijuana.
Barber added, "These patients usually had no other vascular risk factors apart from tobacco, alcohol and other drug usage. Questioning stroke and control patients about cannabis use is likely to obtain unreliable responses."
Although the study is the strongest piece of evidence that associates cannabis with stroke, it should be noted that the conclusions of the study is yet to be published in a peer-reviewed journal. In addition, the connection between cannabis and stroke may be confounded, because all but one of the stroke patients who were marijuana smokers also engaged in tobacco use. However, Barber believed that it was cannabis and not the tobacco that was causing the increased risk of stroke.