MMmm, I am out numbered here.
There are simple chemical reasons for things like schizophrenia which involves excessive activity of the dopamine-receptor system in the brain. That's what they keep telling me.
But considering we only use a small percentage of our brain....... what are the other bits for? Surely evolution would have reduced the brain to it's useful parts and anything which is not used would be phased out over generations.
I think there's sssooo much out there we do not know about.