The issue focused on the study of the effects of high-potency marijuana in high-risk groups, like those with medical problems, that have not been tested in previous research.

"The study is not about whether people who use marijuana are more likely to have some serious medical problem, it's about what the research says about the effects of high-potency marijuana in this group of people," said study author Dr. Paul Armentano, deputy director of the National Organization for the Reform of Marijuana Laws