The Science of Game Addiction
Gamasutra has a report on the state of game addiction science. From the article: "Yes, South Korean and American gamers have died from exhaustion. Yes, this makes bored journalists and unpopular politicians very happy. China has already thrown a fair bit of legislation at video games, whether or not games are the problem. On the other hand, such legislation might fail to address the real problem. In this article I explain addiction simply. Then, I talk about research that attempts to connect addiction to gaming, and some clear problems in that research. One caveat: this article is not going to make anyone into a trained clinician."
This is a pretty good article. I'm a bit surprised that they didn't cover Dr. David Greenfield's research, though - he's dealing with online addiction with a sampling of around 15,000. Also, Nicholas Yu (I think I got that name right) dealt with MMORPG addiction with a sampling around 4,000. Both of their research would be helpful, and probably easily found using Google (I'm just back from class and a long walk home, so I'm not looking anything up right now). I found the work of both of these people invaluable when I was writing the addiction chapter in my EverQuest book.
Robert B. Marks
Author, Demonsbane in Diablo Archive