Gaming is big business. More that 2 billion gamers around the world generated more than 100 billion dollars in game revenues last year. But for some people all the fun is coming at a cost. The World Health Organization wants to classify gaming addiction as a mental health condition for the first time. The addiction is described as a pattern of persistent or recurrent gaming behaviour that takes 'precedence over other life interests'. So how concerned should we be? What's the evidence that people can become addicted? And how severe can the addiction become? Do the types of games that are played - role playing vs. shoot'em up - and the environments they're played in make a difference? And how will improvements to augmented and virtual reality technology change the picture? This week on Newshour Extra Jonny Dymond and a panel of experts look at gaming addiction: serious problem or moral panic? (Photo of addicted gamer by Getty Images)