I'm not sure that I buy this one, but WebMD is reporting that Korean students who spend a lot of time on the Internet may be becoming Internet Addicts and that this is linked to depression, although nobody seems to know which comes first.

The study appears to have been presented at the American Psychological Association conference under the title "NR173 Temperament and Character Patterns of Internet Game Addictions in Adolescents" and tends to read much more specific to Internet gaming than to use in general.

The synopsis (haven't found the full text) discusses traits such as a high dependence on small rewards and low self-directedness (traits measured by a psychiatric test for the study).

Looking on the internet for teenage or adolescent internet addiction (thanks Google), gives us the idea that Koreans may be obsessed with determining if their kids are obsessed with the net, but that's another issue altogether.