Hi Lisa,   Marijuana use, over prolonged time, particularly heavy use of marijuana, can actually cause SZ symptoms.  What your son is doing is "self-medicating," and that is never a good idea for someone with SZ.  I hope he is taking his antipsychotic to get relief from the voices and hallucinations.  Smoking pot is never a good idea to control SZ symptoms.   Everyone I know who smoked pot, regardless of whether or not they had SZ, could barely function in society.  The fact that your son gets As in school I would be leery of attributing to the pot smoking.  The longer he is in recovery, the better his chances will be, especially if he got early treatment for his symptoms.   No expert I know, no one I know who is diagnosed with SZ, would ever make the case for continued marijuana use by someone with SZ.   Regards, Christina