I think it's absolutely universally accepted that stress is a major factor in autoimmune and inflammatory disease. Reducing stress by working on mental health definitely has the potential to reduce inflammation levels in some people to the point where you need no medication.
But like everything it's not a silver bullet.
Another weird/fascinating factor for me at least is that less convenient access to a toilet seems to correlate with less symptoms. When I'm hiking in the mountains I never seem to have a high frequency of needing to take a dump. I've often wondered if there is something of an explanation there for the rise in rate of Crohn's diagnosis in countries as they develop.