At the end of the day, we really don't know that much about how the brain and mind actually work. The deep, dark secrets of the neuron have been eluding mankind for decades, if not longer.

I think too many "disorders" these days stem from the fact that we're actually clueless about how our brains function. As always in human history...that which we don't understand tends to be thrown to the idea of superstition, witchcraft, religion, etc.