Marijuana cannot be used during the round regardless whether a person has a permit to legally use it in the state. It's the same with alcohol which cannot be consumed by players during the round even if they are old enough and the park allows it. These items can be consumed before, between or after rounds if they can legally do so based on age, license and/or permission granted by the venue. If a player is so disabled that they cannot do without medical marijuana for the length of a round, they are simply too disabled to play. Contact Gentry if you wish to discuss your specific situation:
dgentry@pdga.com