Wisconsin allows people to use CBD, a non-psychoactive ingredient of marijuana, if they have a doctor’s note — a requirement Evers wants to eliminate. CBD can be obtained from hemp produced through programs authorized by the state, said Mike Queensland, an attorney with the Wisconsin Legislative Council.

Research shows cannabis can ease pain, nausea and muscle spasms, but evidence for other therapeutic benefits is scant, said Dr. Robert Wallace, a University of Iowa epidemiologist who helped write a 2017 national report that summarizes marijuana’s health effects.

The federal government considers marijuana a Schedule 1 drug — the most restrictive of federal drug categories — and that makes it difficult to study, Wallace said. In studies involving “street” cannabis, it’s hard to know what kind of pot people are using and rule out other drug use, he said.

Traffic fatalities increased in Colorado and Washington after those states legalized recreational marijuana, Wallace said. Cannabis use doesn’t increase cancer risk, as tobacco smoking does, but it can make psychosis worse, he said.