People in richer nations report to be happier and a higher life satisfaction than people from poorer nations. Most countries now have higher self reported life satisfaction and happiness than in the past.

Rates of mental health disorders haven't changed much during the last 30 years.

https://ourworldindata.org/grapher/gdp-vs-happiness

https://ourworldindata.org/happiness-and-life-satisfaction

https://ourworldindata.org/global-mental-health