In the final installment of three-part essay for Slate, Marie Myung Ok-Lee reflects on the challenges she has faced after deciding to treat her 9-year-old autistic son with medical marijuana. She reports that pot has helped his condition greatly. But the therapy exists in a legal gray zone, and even finding a consistent supply of the most effective strain — a custom-bred hybrid called "White Russian" — has been an ordeal:

"Last summer, we reached the six-month mark in our cannabis experiment. We'd been using medical marijuana to help quell our autistic son's gut pain and anxiety, and we were seeing some huge changes in his behavior and, presumably, his happiness. J was smiling, interacting (one of home-based therapists said she'd never encountered such an affectionate autistic child), even putting his dirty dishes in the dishwasher....

"The more I'd been reading, along with J's doctor, about the effects of cannabis—analgesic, anti-anxiety, safe—the more it seemed a logical choice. I've also heard from other parents who've decided to try cannabis for their children. [One] is an autistic child who'd refused to eat and was near death. Post-marijuana, he is thriving."

Read the whole essay at Slate.