A 1998 study "proved" that using the Internet causes depression. It was the classic fallacy of confusing an association with causality. Here's the prototype:

If you put everybody who takes aspirin into one group, and everybody who never takes aspirin into a second group, you'll find that people who get headaches belong predominantly to the first group. Therefor taking aspirin causes headaches.

What a sophomoric mistake for supposed professionals to fall into!

And if being depressed "causes" people to use the Internet, maybe that's because they can now have some kind of humanizing social life even though they're paraplegic, or blind, or the only gay grandma in town, or a ten-year-old with a 180 I.Q., or just not the prettiest girl in school. For my money, that's just one more reason to be thankful to the greatest technological advance in human communications since the printing press.

First thing we do, let's kill all the statisticians.