The people who's entire lives get wrapped up in the game have issues to begin with and it just happened that this game sparked their obsessiveness off onto a whole new level. If it wasn't WoW, it would have been something else. If you let any one aspect of your life control everything else you're weak to begin with.

As for stories, like everyone else I've HEARD of people loosing their job/gf/sanity over the game however never knew someone personally to get that sucked in. I did however hear of a murder in japan on the radio quite recently about a son who stabbed his father after he turned off the internet mid wow session. Japanese people are insane and on the edge as it is though.