Honestly, this question pisses me off so much I can't even tell you. Do you know what causes psychosis? Paxil, Prozac, Wellbutrin, lithium, etc....and it causes much more too. My mother in law and ex best friend are enormously obese and that is not good for the body or mind...they have lots of health problems, undeniably caused from the weight. How would overweight people feel if I constantly tried to tell them what they already know ....food is killing you!!! Obviously it's worth it to them, just like psych meds which can and do shorten lifespan and lead to suicide. It's up to the person what they choose to put in their mouths. If that food provides them short term comfort at a long term price, it's up to them to make that decision. Unless of course the person is developmentally delayed and incapable of making a decision for themselves, I highly doubt anything you have to say regarding pot and the "what if's" of it are going to matter. They'd have to be pretty darn stupid if they didn't know the cost/benefit analysis for themselves. I have never had psychosis as a direct result of pot but have from psych meds. Should I not take psych meds? I realize my anger is misdirected and I imagine you just want to help your friend. Your judgement will not help your friend.