An anonymous reader sends this excerpt from Medical Daily:
"Researchers led by Sriram Chellappan from the Missouri University of Science and Technology, collected internet usage data from 216 college students enrolled at the university. The usage data was collected anonymously without interfering with the student’s normal internet usage for a month. The students were tested to see if they had symptoms of depression and analyzed internet usage based on the results. Depressed students tended to use the internet in much different ways than their non-depressed classmates. Depressed students used file-sharing programs, like torrents or online sharing sites, more than non-depressed students (PDF). Depressed students also chatted more and sent more emails out. Online video viewing and game playing were also more popular for depressed students."