Key findings.
Depression seems to start increasing around 2011 for leftist girls, and then with some delay, other groups follow. Smartphones? Social media? Foundation of great awokening?
It has gotten somewhat extreme. A majority (!) of young leftist women now say a healthcare provider told them they have a mental health condition. That's insane!
But the link between political leftism and mental health goes deep, and long back. And, no, it's not just religiousness.
It does seem to be a particularly European (White) thing, as there's a bigger relationship in this group (in USA).
Leftism as reversed cognitive behavioral therapy. Very apt description!
"The well-being gap between liberals and conservatives is one of the most robust patterns in social science research."
I wouldn't go that far because it is culturally dependent, but yes, insofar as social science goes, this relationship is well established in Western countries.