Afaik (and I watch this fairly closely) there hasn't been a study. There are a lot of anecdotes, typically of the form "a person won a few million but spent like they had an income of a few million per year," sometimes of the form "a person won a huge amount of money but it turns out money doesn't solve all problems," and sometimes of the form "a person won a huge amount of money and invested it poorly." But most people who win a big lottery are still rich a decade or two later.
Even those who would be deemed "responsible" (already somewhat wealthy, otherwise stable) often end up far worse off.
It often ends in losing friendships, ties with family, death/kidnapping/blackmail threats both close and far away, endless frivolous lawsuits, financial ruin, etc.
The ratio of "happily ever after" stories to horror stories for winning the lottery seems a bit low for my tastes.
That’s just survivorship bias (or perhaps, the opposite).
You don’t hear the happily ever after stories because they don’t tend to reach out to the media after a few years and say “Hey! FYI I’m still rich and my life is perfect.”. They’re off enjoying their money somewhere. The scandals seem more common because those are the only situations that really get publicized.
