[ajarmst]

The brain is an absurdly complex, adaptive system that is the product of millions of years of evolution. We're not even really sure where personality and the "me" part of the self come from, other than that they seem to have a stronger genetic component than most people realize. We don't understand how it works remotely well enough to have a useful whole-brain model of its function (which means a lot of drug research is a primitive try-it-and-see-what-happens method, rather than the result of a detailed functional model of what SHOULD happen). We don't understand most of its more subtle pathologies (like depression) well enough to even properly evaluate treatments. Most treatments we do have for such things are of limited and short-term efficacy, and we don't even understand why they work. Maybe we're not nearly ready to start large-scale manipulation of its fundamental properties?