drug induced psychosis through marijuana is an incredible rarity. i'm relatively certain that it's possible to reach a state of psychosis through consuming enough thc (bceause I glanced at the DSM-IV once), but the limit is beyond what you'd get if you were smoking/vaporizing the drug. You'd actually have to eat a shitload of concentrated thc, so much that you couldn't really do it by accident unless you were some special kind of stupid. So what's your point again?