Social media use increases depression in preteens, not vice versa

That's some great correlation, but does not imply causation. The study helps firm up the causal link, but your "makes sense" implies that the causation is intuitive but I don't think it is.

Yeah agreed. One of the first things I do when I start feeling blue is to stop using social media and go camping.

Yuppers. Social media makes us compare each other to the best versions of people online.

It really helps me to remember that everything online is a version or product of what that person/company wants you to see. It isn't real.