That's fucking ridiculous, let's just pick and choose attributes societally deemed less desirable and throw them right in the dsm-5. At what point do you recognize a dichotomy between personal difference and mental conditions. I'd classify excessive gaming as a symptom of another undiagnosed condition or social problem i.e. (dysfunctional family, child abuse, bullying, Asperger's...). While we're at it lets throw excessive cell phone use into the dsm-5 as I abhor cell phones and practically all forms of social media.
Why single out video games? I'm guessing the WHO is targeting gaming since its more common among children and adolescent, an age group that is not among their ranks. Will we see a seperate additional disorder of Excessive Facebooking in the future.