I apologise Loosehead, I only scanned the thread.
I still think it's about quantity and predisposal to medical conditions. My aunt has a range of mental disorders, psychosis and pathalogical lying which fall under some sort of identity disorder and cant remember what it is, might be histironic identity disorder. She probably did smoke a few joints in her teens, but I did too, and I reckon way more than she did, so why did I end up the way I did and she did the way she has?
Heroin has a similar bad press on these things but many psychiatrists believe that drug abuse and the onset of mental illness are hard to distinguish and some users use to surpress the feelings they have in an illness. Please don't think I think heroin is a good thing, have never taken it and never ever would and I would chop off my arm before I ever took it.