Autism

Also just the culture of lying which can grow or shink in any society, if it grows, will lead to everyone having more anxiety as a result of not being able to trust the information they're getting. People being unreliable, breaking promises, it can all feed on itself. Other's mental illness makes them less predictable, less conducive to support and healthy interaction. So it can spread. There can be epidemics of mental illness too.

Any kind of stress increase can degrade and eventually break a person's mental health. Complexity is a source of stress, and as our own mental health breaks down, and our own ability to be there for others consistently breaks down, we add complexity to their lives.

When others can trust us, we save them mental energy. They can make one plan instead of having to make two -- one for if we fulfill our promises and one for if we don't. And when we can trust others, they save us mental energy in the same way.

So culture and even overall levels of mental illness themselves are inputs into the question "how stressful is it to live in X society?"

I think the inequality feeds into this with a lack of respect. When you have to big groups of people who aren't mixed socially, ie distinct social classes, it can lead to contempt and distrust. That contempt and distrust means we're all surrounded daily by people we can't count on. Situations we can't count on. Jobs that we don't know will be there next month, because what if they break their promise not to lay people off, or they break their promise that "These are your duties: X, Y, Z" and try to add "A, B, and C" to our duties.

Poverty itself is bearable, if the systems one is interacting with are reliable enough that one can know exactly what the relationship between effort and output is going to be. But when those systems change all the time, and the same paycheck could require more and more work to the point we can't keep up, or whole divisions are being shut down or bought out or whatever, or the value of the dollar keeps dropping so the same grocery budget suddenly isn't enough, or the electricity goes off and you can't get your work done, or they suddenly don't have hours for you, those kinds of things are the real source of stress in poverty.

The level of disrespect, manifested in a constantly-changing environment one has to adapt to when poor, in order to keep from getting drastically more poor, the constant changing of thee rules, these are poison for people living on little.