I don't think markets and mental health are quite as intimately related. I think it's more to do with living in an individualistic society where we have less of a social net to fall back on. And I mean 'social' as in a close-knit community, nothing political.
I think there is a missing institution that should exist to protect people from market effects.
The raw edge of the market is driving a wedge into people's lives. People need to be protected but they're just a few decisions away from loss.
Society doesn't do enough for the losers of the world, it's a winner take all system.