Progressivism is linked to the ‘openness to experience’ personality trait which overlaps with neuroticism not to mention a greater tendency to experiment with substances. That would be my off-the-cuff theorising to explain this phenomenon. https://twitter.com/ZachG932/status/1248823584111439872

Zach findings are not the first time this link has been mentioned/queried. Remember that the SlateStarCodex guy (Scott Alexander) is a Psychiatrist. https://twitter.com/phl43/status/1227338353101672450?s=20

‘Openness to experience’ trait linked to how you voted on Brexit in my opinion. Its interesting to speculate anyway. https://twitter.com/post_liberal/status/1179483622925045760?s=20

‘Openness to experience‘ & ‘neuroticism’ overlapping sounds counter-intuitive but apparently it is the case. Pretty well established that progs, in general, are more ‘open to experience’ than cons, see Righteous Mind, Ed West’s new book, for more details.

https://www.closer.ac.uk/news-opinion/news/neurotics-thrillseekers-common/

If progressivism defined by greater ‘openness to experience’ & if this trait is linked to neuroticism, which is itself linked to a predisposition to develop symptoms of mental illness of all kinds, stands to reason that progressivism & mental illness would be linked in some way.

Add in a greater tendency to experiment with drugs to compound this bc, believe it it or not, substance misuse and mental illness follow each other as night follows day.

None of this should be controversial unless you are a blank slatist who thinks that a baby is a tabula rasa when born and if you are then you can safely be ignored bc you clearly don't know what what you are talking about.