He attributes the cause to Iphones and Facebook, but cannot prove it.
He says at 26:40 that now 54% of young liberal White women now answer Yes to the question: Has a doctor or mental health professional ever told you that you have a mental health problem?
This is stunning. If you told me that some group has X% admitting to a diagnosed mental health problem, then I would assume that the true mental illness incidence is more like 2X% or 3X%. But that would make them all mentally ill!
Haidt says these trends are happening all over the Anglosphere and in many other countries, but not everywhere.
He says the trend pre-dated the Donald Trump campaign, and helped make his election possible.
I am not convinced that this can be blamed on Iphones and Facebook. Maybe there was some infectious agent or alien brainwashing. Maybe it is the culmination of several decades of feminism.
This is another reason to rethink democracy. I do not see how it can work, if half the population is mentally ill. Haidt gives examples of crazy things that are commonly told to women, and which women believe.