This is a pretty unimpeachable causal identification strategy finding Facebook's rollout caused worse mental health issues https://www.aeaweb.org/articles?id=10

This is a pretty unimpeachable causal identification strategy finding Facebook's rollout caused worse mental health issues https://www.aeaweb.org/articles?id=10.1257/aer.20211218 https://www.aeaweb.org/articles?id=10.1257/aer.20211218 It's hard to do similarly high quality studies today because no one rolls social media out gradually anymore.