Questionable New Zealand study shows marijuana could double the risk for a stroke


Last week, scientists in New Zealand announced the findings of a “study” they did on the correlation between cannabis use and certain types of strokes. Despite the shaky science, the finding has been moved around the world by now on dozens of media outlets — most of which aren’t questioning what’s behind it.

And first reported by, Dr. Alan Barber, with the University of Auckland conducted the experiment, which is based on data collected from hospital visits alone and with no other information except what type of stroke the person had and their testing for cannabis.

American Heart Association.
Dr. Alan Barber

Out of 160 stroke patients, about 16 percent had marijuana in their system. The doctors then compared that to 160 control-group patients of roughly the same age, gender and ethnicity admitted to the same hospital. That group had about 8 percent testing positive for cannabis.
Despite other studies showing that cannabis can help the brain protect itself from strokes, these Kiwi scientists insist that ganja is the culprit here and that this study shows you’re twice as likely to have a stroke if you smoke marijuana than if you don’t.
“The study doesn’t prove that smoking pot will cause a stroke. But it provides the strongest evidence to date that a lifestyle that includes cannabis use is closely associated with a doubling of stroke risk,” Barber told “For starters, this is a young age group to be having strokes, and many didn’t have any of the traditional risk factors,” he said – completely avoiding the fact that all but one of the cannabis-using stroke victims was also a cigarette smoker.
It’s not like cigarette smoking nearly doubles your risk of having a stroke or anything like that. Oh wait. It does. The rate of an ischemic stroke in smokers is almost twice as high someone who isn’t a smoker. And yet this doctor doesn’t consider that a “traditional risk factor.” Really.
Finally, it should be pointed out that the study hasn’t even been through the peer-review process – an essential part of the process for an academic or scientific study to really have any merit. So basically, right now we’ve got one man and his study that hasn’t really even undergone any scrutiny from other scientists and academics. Barber says he’s likely going to revamp his study to account for tobacco and other factors. We say he should have done that the first damn time.
While the study doesn’t deserve the merit it’s been getting, the increase of strokes among people under 55 is actually increasing. Scientists attribute much of that to genetic factors like high cholesterol and hypertension, but also point out that our generation seems to battle things like obesity, lack of exercise, excessive alcohol consumption and tobacco that can be avoided.
New Zealand is often said to be in the top three English-speaking countries for cannabis consumption in the world behind the United States and Canada. According to the United Nations, about 14 percent of their population of 4.4 million people having used it at one time. Kiwis between the ages of 15 and 45 have the highest usage rates, with about 17 percent admitting to puffing.