I think this is a much more complex matter than just blaming it on smart phones and social media.
Young Adulthood Is No Longer One of Life’s Happiest Times
The U-shaped curve that pegged youth and old age as the happiest times of life has changed
https://www.scientificamerican.com/article/young-adulthood-is-no-longer-one-of-lifes-happiest-times/
I think this is a much more complex matter than just blaming it on smart phones and social media.