https://jonathanhaidt.substack.com/p/international-mental-il...
Salient points:
In sum, all five Anglosphere countries [US, UK, CA, AUS, NZ] exhibit the same basic pattern:
A) A substantial increase in adolescent anxiety and depression rates begins in the early 2010s.
B) A substantial increase in adolescent self-harm rates or psychiatric hospitalizations begins in the early 2010s.
C) The increases are larger for girls than for boys (in absolute terms).
D) The increases are larger for Gen Z than for older generations (in absolute terms).
Why did this happen in the same way at the same time in five different countries? What could have affected girls around the English-speaking world so strongly and in such a synchronized way?
[...]
At this point, there is only one theory we know of that can explain why the same thing happened to girls in so many countries at the same time: the rapid global movement from flip phones (where you can’t do social media) to smartphones and the phone-based childhood. The first smartphone with a front-facing camera (the iPhone 4) came out in 2010, just as teens were trading in their flip phones for smartphones in large numbers. (Few teens owned an iPhone in its first few years). Facebook bought Instagram in 2012, which gave the platform a huge boost in publicity and users. So 2012 was the first year that very large numbers of girls in the developed world were spending hours each day posting photos of themselves and scrolling through hundreds of carefully edited photos of other girls.