Interesting report on the relationship between inequality and mental illness in the Guardian:
The basic story in this research (by Lynne Friedli for the World Health Organization) seems to be that even in rich societies mental health problems result from inequality - because of stress caused by income insecurity and status problems, which will be higher in more unequal societies.
This is intuitively almost obvious: a poor American in some neglected urban ghetto still usually will have a high income by world standards, yet it would seem ridiculous to argue that someone at the bottom of the social heap in the US will be happier than someone with average income in a poorer society (and nearly all societies are considerably poorer than the United States).
The implications of these findings are important. Even if we accept that there is a trade-off between economic performance and equality - which I don't - the fact that inequality may make people ill even when they're rich suggests that we should do without extra economic growth that is likely to be achieved at the expense of fairness and equity.
Of course, the high inequalities of the era of financial deregulation don't seem for the moment to have worked out so well in economic terms either. But the WHO research shows that even while that model seemed to be working, it was probably not working for most people and was positively noxious for quite a few.