The game has become an obsession for some players."The problem with World of Warcraft is the degree it can impact and create a socially withdrawn figure who may be connecting with people in the game and is largely dropping out of education, social opportunities," he told The Telegraph.

Brett Close, chief executive and president of 38 Studios, which is developing a new fantasy MMO game, said about 80 percent of MMO games fail but companies continue to try as the appeal is that players become part of that world and spend to stay there.Dr Richard Graham, a child psychiatrist at the UK's Tavistock Center, was reported as warning last week that some young people were damaging their social and mental development by playing the game for up to 16 hours at a time.But its success among gamers has rival publishers struggling to get into the increasingly popular MMO market.