Ken Mackey

As a Schedule III drug, marijuana would still be a controlled substance, but with recognized medical use.

Attorneys General of Nebraska, Indiana, Iowa, Idaho, Kansas, Louisiana, Oklahoma, and Wyoming wrote in a statement that the science surrounding marijuana shows it cannot be used safely.

Ken Mackey is a professor of neuroscience at Indiana University.

He says marijuana is an effective treatment for chronic pain,

and its potential for abuse is lower than other drugs, such as tobacco.

Trump's order does not immediately reschedule marijuana, but directs the U.S.

Attorney General to expedite that process.

For NPR News, I'm Ethan Sandweiss.