The World Health Organisation is on the verge of officially recognising a phenomenon that researchers have been studying since the Super Nintendo era: video game addiction. Scientists and public health advocates who back the move say that compulsive video-game playing is a discrete disorder that can seriously damage a person's mental and physical health. But other experts say that classifying a common behaviour like gaming as a potential disease is scientifically unsound and might even repopularise an old stigma against gamers.