(adsbygoogle = window.adsbygoogle || []).push({}); Roughly 20% of the developed world population suffers from a mental disorder of some sort. If the human brain has been evolving for the last ~200,000 years, wouldn't you expect the number to be a lot lower? The prevalence of mental disorders could be due to many things, but it seems as if that they aren't disappearing with evolutional advancements. Could they provide an aid to the individual that is not completely obvious? Could this benefit be translated into one that is beneficial to society?

For example something as crippling as depression and neuroticism can allow the individual to become more self-aware, allowing them to improve on themselves.

Schizophrenia: higher resistance to shock, increased resistance to physiological substances, and probably many other benefits.

Still not sold?
Psychopathy: psychopaths are assertive, psychopaths don’t procrastinate, psychopaths tend to focus on the positive, psychopaths don’t take matters personally, psychopaths don't get upset if things go wrong, psychopaths work well under stress.

All of these can be seen as evolutionary benefits, but could these benefits translate into societal benefits? For example psychopaths are often in executive positions, which they preform well in because of their ability to make decisions without second-guessing themselves or worrying about the outreaching effect it might have on other people.