I can't find any study looking for a direct link between social media use in children and depression. Most articles I can find can only find correlations, but there's no indicator of if depressed kids start to use social media more or if kids using social media become depressed.

I have found articles linking social media to worse sleep quality (and sleep quality and depression are well known to influence each other) but still no direct link.

Do you happen to know what papers prove the link between depression and social media use in children? The theory makes sense but I can't find studies that prove more than mete correlation.