If I don't smoke my mental health suffers greatly. In fact if I go too long without smoking I go from a successful and productive member of society to a bum who can't form a proper sentence. My mind races 24 hours a day. At any given sober time I am thinking about multiple unrelated random shit. It is very very hard to do even a simple task when you're thinking about a bunch of other shit that's unrelated. I was given adderall for it, which it did slow my mind down and allow me to focus, but my mind is the only thing it slowed down. Adderall made me tweak out and not sleep which is not good for someone with chronic insomnia like my self. Marijuana has the same effect of slowing my mind down allowing me to focus on one thought or task at a time without the nasty side effect of feeling like I just smoked a $50 rock. If I don't smoke my racing mind will keep me up for 5, 6, 7 days at a time. After several days of no sleep you start becoming detached from reality, and eventually you start becoming delusional. Also I used to get these killer migraines from the constant flow of dumb ass thoughts rushing in and out of my head. I have this prescription drug for my migraines, Relpax, and it works. But since I smoke every day I don't get migraines, and haven't taken my Relpax in ages. Granted I don't have schizophrenia, people with that mental illness should probably steer clear of reefer/