Angeliki Kastanis

Associated Press

In this April 26, 2019, photo, medical marijuana cardholder Scott Donnelly, assisted by his wife and licensed caregiver, Vicki Poppen, leaves Western Oregon Dispensary in Sherwood, Ore., after buying medical marijuana to treat muscle spasms caused by his multiple sclerosis. Donnelly visits the medical-only dispensary once a week and relies on it for the cannabis that eases his tremors long enough that he can fall asleep. The dispensary is one of two medical-only shops left in Oregon.

Legal Pot Ups Cost of Medical Weed

States see a "massive exodus" of medical patients when they legalize marijuana for all adults — and then, in many cases, the remaining ones struggle.