Gallup's global survey of positive and negative emotions sheds some interesting light on the proposition that smartphones are harming young people. Here are positive emotions:
There's no change after 2012, when smartphones became widely used. Now here are negative emotions:
Negative emotions did start to rise around 2012. However, this was a broad trend that had nothing to do specifically with young people. Everyone is becoming more negative. Also, this peaked in 2020 and has been declining ever since. If smartphones are the cause, why would that be?
This is a very limited look at things since it includes the whole world, not just the US or even just rich countries. Nor does it break things down by gender, which might be important. However, we do have individual country ratings for certain emotions, and they tell us that overall the US is about average on most things—including sadness—with the exception of stress, where we rate high, and loneliness, where we rate low.
Gallup has all the detailed data necessary to produce annual charts by age for just the US. In fact, it's available to anyone who subscribes to their service, which doesn't include me. But whether it's Gallup or a subscriber, it would sure be nice if someone could replicate the two charts above just for the US, broken down by gender.