The more society becomes increasingly oriented around thought-work the more these problems will manifest. Humans evolved to cooperate, but we didn't evolve to spend all day thinking about long-term work-related stressors that are only indirectly related to our own well-being. Once it became trivially easy to obtain food, water, and shelter, a good portion of our biological imperative was left without anything to be concerned with.

For an interesting tangentially-related thought, try asking people what the definition of "healthy" is for a human. Mental health is the hardest part to define out of all health.