They say "frequent gamers" were the target of the study, clearly what they meant to say was obsessive gamers... I mean c'mon, reaching for a controller? Seeing HP bars? Sounds like some sort of dissociative disorder. I spend over 90% of my time gaming, or working on my PC, never have I had an episode like this. I have personally witnessed people with this sort of issue, and they were either "permafried" from drug abuse, or actually had a diagnosed dissociative disorder. This might have some correlation between the obsessive gaming behavour, and the GTP.
Also, I blame the schools, and the parents, they're both on the downfall as far as quality goes. I bet if they tested older gamers, they wouldn't find such disturbing results. If people mentioned their ages here with their claims of personal experience with this, you'd probably find many of them are of the younger crowd (sub 25~, and I've been looking at people's profiles myself to see if this is so.)