HYPOTHESIS: Johnathan Haidt thinks the teen mental illness epidemic began around 2012 because he published The Righteous Mind in 2012 and got a fuckton more traffic to his survey site, yourmorals.org.

He's hardly the first person to notice the problem. Sherry Turkle started in on it in '81 and has done five or six books since. danah boyd made a big splash in 2014 saying pretty much the same shit as Sherry Turkle in general or the three or four Frontline episodes on the same subject since 2006. Haidt's working with Jean Twenge, whose book is shit and has nothing to add to danah boyd's or Sherry Turkle's since 2017. Here's an RSA on the rise of ADHD and depression as related to the rise of screens from 2010:

Instagram launched in 2010 and was bought by Facebook in 2012. We saw their internal polling what, last year?

So any mental health professional you care to consult will go "yeah, online stuff ain't healthy for kids." The problem here is that Johnathan Haidt mostly seems to use his blog and substack to pick fight with Twitter critics so it's not like any of this will be particularly edifying. Did it begin in 2012? Does it matter? The important thing is it's yet another attractive nuisance that people aren't insisting isn't a problem and will continue to do so until it's obviously a problem. Remember - Dr. Spock said you should let kids watch as much TV as they want until the 1973 edition.