Claire Caulfield/KJZZ

Medical marijuana buds in glass jars at a dispensary in Scottsdale.

Arizona lawmakers voted to require warning labels on medical marijuana on Tuesday. The measure would also use proceeds from a new tax to study any link between the drug and schizophrenia or violent behavior. 

Democratic Rep. Pamela Powers-Hannley says the measure does not require those state-funded studies to be done in a scientific way.

"There's a lot to research. But the violent behavior thing really surprises me because, again, people have high THC are usually falling asleep in front of the TV set," Powers-Hannley said. 

Republican House Speaker Rusty Bowers is behind the proposal. Bowers is citing research from a book called, “Tell Your Children,” which has been criticized by some scholars and clinicians for its flawed methodology and cherry-picked data.

The bill would still have to go on the ballot in November since lawmakers cannot make changes to voter-approved measures.