Meta-analysis, very large, shows small correlation between unhappiness and social media use: https://jamanetwork.com/journals/jamapediatrics/fullarticle/...

Large AU observational study. Moderate social media use correlates to the happiest kids, high use and no use correlates to unhappiness: https://jamanetwork.com/journals/jamapediatrics/article-abst...

Swedish obervational study, after adjusting the data there was no correlation: https://www.jahonline.org/article/S1054-139X(26)00162-X/full...

I can't find the specific inverventional study I mentioned. As I recall, it was mixed but possibly I remembered wrongly.

Some studies do show a significant correlation between unhappiness and social media use, but causation has not been established and the bigger, better done studies have weaker correlations. People believe in causation because it suits their bias against social media.

I dislike social media but I doubt it's harmful. This substack summarizes my view on what really makes children unhappy: https://substack.com/home/post/p-186087964 (school). I'd guess that lack of freedom is what makes school so awful; modern schools are like little totalitarian states, where every minute of your day is accounted for and there is no privacy.