Doesn't the research on happiness say that by and large you can't change happiness? That thing about people who've won the lottery or gotten seriously ill?
Money can improve happiness, but there are diminishing returns to money. Winning the lottery is really one of the worst possible ways to improve one's happiness. For example:
1) Wanting to be ultra-wealthy is arguably a vice rather than a virtue. A form of gluttony. It doesn't make you a better person.
2) Hardly anyone is prepared for the massive, sudden change in lifestyle brought by winning the lottery. Not to mention that everyone you ever knew, and also people you never knew, suddenly want a piece of you and your newfound money.
We talk a lot about big lottery winners, because it's fun to imagine, but it would honestly be better for most people to win $10K or $100K rather than winning $10M or $100M. You can improve their lives without radically changing their lives, which can be a curse rather than a blessing.
Unless you already have a very specific idea of what you would do with lottery winnings, e.g., start a business or foundation that required $X million in capital, a newfound giant pile of unanticipated money doesn't necessarily do you good. Money needs a purpose.
I'm not familiar with the research, but from experience, you can change it without a doubt. Happiness is an outcome, if you change things that prevent it then you'll have better chances of achieving it.
Tons of money alone is not a guarantee of happiness, there's a cutoff of income beyond which happiness maxes out. Getting seriously ill can of course induce depressive traits, however I've just seen a documentary about using psychedelics for cancer patients and it did improve their lives significantly, although not curing cancer itself.
I'm not familiar with the research you mention (it would be great if you could cite it), but from reading and thinking about this, I'd say that happiness is intrinsic, and that external factors can't change it.
If you were miserable before winning the lottery, the money probably won't change that. If you have a bright outcome on life before getting cancer, you're more likely to cope and stay happy.
