I knew a number of people who use the medicinal aspects successfully. Medicinal mj here in Colorado was never used in the old time ways, it was just a way to de-stigmatize recreational use. Shortly after recreational use was allowed, kids would show up at school fine, then after a recess would be experiencing symptoms of over dosing. As they investigated, it turned out the major source of their pot was what they stole from grandma, the parents weren't into it. Just look for the blasted old ladies in tie dye.