This study found that almost 1 in 3 students at the Missouri University for Science and Technology, who have the spare time to take part in psychology research, are depressed. Then this study tracked the internet usage of those depressed students to see how depressed people interact with internet services differently than non-depressed people.
I read the article didn't see any claim that these patterns of usage caused depression. The emphasis seemed to be on using them as a signal for diagnosis of a pre-existing depression.
