Mr. Reid said he began changing his mind about medical marijuana laws after witnessing the health struggles of people who would have been helped by the drug. One of those cases, he said, involved the son of an unnamed Las Vegas official.

“He was so skinny and doing so poorly, and someone told him and his mom, you know, you should smoke some marijuana,” he told The Sun in an interview published on its website on Thursday afternoon. “You get the munchies, you get extremely hungry.”

After the son gained weight, Mr. Reid said, “I thought, you know there might be some medical reasons to taking another look at this.”