What they said on "If Books Could Kill" is an extremely thorough trouncing of Haidt's narrative and the methodologies of the researches he utilized in that book.
The summary is this:
The uptick is adequately explained by changes to mandatory reporting requirements for screening questions of mental health for teenagers from Obamacare and increased access to healthcare for those teenagers.
So mental illness rose steeply in girls and not so much in boys since 2012, and more in liberals than conservatives, since 2012 and this is adequately explained by increased reporting requirements?