“Long-Run Effects of Lottery Wealth on Psychological Well-Being”, Erik Lindqvist, Robert Östling, David Cesarini2020-02-12 (; backlinks; similar)⁠:

We surveyed a large sample of Swedish lottery players about their psychological well-being 5–22 years after a major lottery event and analyzed the data following pre-registered procedures.

Relative to matched controls, large-prize winners experience sustained increases in overall life satisfaction that persist for over a decade and show no evidence of dissipating over time.

The estimated treatment effects on happiness and mental health are statistically-significantly smaller.

Follow-up analyses of domain-specific aspects of life satisfaction implicate financial life satisfaction as an important mediator for the long-run increase in overall life satisfaction.