how much confidence

Lower than it was when I posted it, but it seems plausible enough to be worth discussing.

I would now dispute the use of 'most'.

what evidence

observations of cultural memes, seeing how people talk about it with victims, seeing how role models talk about it, and observations of people dealing with similar but unrelated pressures.

All of this is very easily screened off by closer evidence, I would like to see some more solid studies or more stories at least.