The difference is that compulsive gamers have little control over their play time. If you play games for long periods of time, it does not mean you are compulsive, if you do it by choice, because let's say, you have nothing better to do. You are compulsive if you just can not simply stop playing game. It boils down to the difference in brain connectivity, because it is impossible to differentiate the two only looking at behavior over some period of time.
