WIKIMEDIA, HUPU2Researchers have been studying the effects of smoking marijuana, either for recreation or as a therapy, for decades. But even as use of the drug becomes ever more popular—and ever more legal—science still has a relatively poor grasp on the health benefits or drawbacks associated with smoking weed.

This is one of the main take home messages from a National Academies of Science, Engineering, and Medicine report released today (January 12) that collates recent research findings on the health effects of cannabis and cannabinoids. The report was compiled by a committee of researchers and public health officials, who combed through more than 10,000 abstracts published since 1999.

“For years the landscape of marijuana use has been rapidly shifting as more and more states are legalizing cannabis for the treatment of medical conditions and recreational use,” Harvard University public health researcher Marie McCormick, chair of the committee, said in...