It has long been known(1940's)that first use of cannabis will (rarely) lead to an imediate profound psychotic break, sometimes permanent.
And amongst the rastas I have heard it said that it is "not for stupid people", along with other things :)
A friend and roomate of mine had his first break after a night like this.
He overindulged on his first use, slept it off, and woke up a paranoid schizophrenic. Paced around the house talking to himself and accusing me of things.
Perhaps unrelated but I find it hard to believe. His parents came and were very mad at me, took him away and I never spoke to him again. His father suffered from it as well I later found out.
