Hello,
I am a director for a youth prevention program as well as a youth pastor, and I frequently do research on this subject. As a result, I stumbled across this post. Today I was reading a drug info pamphlet and some of the side effects of drugs. I decided to google and see what other people were experiencing.
One thing I know from research and experience within my own family, substance abuse can trigger mental illness and psychotic episodes. It happened to my brother who is now schizophrenic. Whether he was predisposed to begin with, we will never know; but he will never, ever be the same. Be careful! Drugs artificially produce dopamine in the brain. In healthy brains, dopamine will decrease as to not cause an overload, resulting in psychosis. Dopamine is a feel good hormone. Abuse of drugs causes the brain to no longer produce dopamine naturally, therefore becoming dependent on the substance. Also, with some people, I believe (as in my brother), their brain may not decrease dopamine when the drug is consumed, again, resulting in psychosis. Make sense? I hope you know my intentions are good here

Best wishes to you!