The most interesting thing about the Smartphone Theory of Everything is that it's really a Smartphone Theory of Everything in America and the English-Speaking World.

While phones are everywhere, the problems that they cause are often rising fastest and first in the richest countries, especially in the U.S.

• Youth sadness? Surging in the Anglosphere, but almost nowhere else.

• Attention disorders? Skyrocketing in the U.S., but not Europe.

• Populism, distrust, polarization? Much larger effects in the U.S. than other countries.

The version of the SToE that is most defensible given the best data we have is something like this:

Compulsive phone use along with under-regulated social media produce widespread youth anxiety, attention issues, polarization, populism, and institutional distrust in:

1. highly individualistic societies, with

2. a culture of diagnostic inflation [i.e., expanded diagnostic guidelines for anxiety and ADHD], plus

3. negative-affect prevalence [i.e., people online constantly talking about their anxiety and ADHD], and finally

4. high levels of negativity in their news ecosystem ...

and post-2010 America was simply the first and most dramatic example of all these ingredients coming together.