If they are spending too much of their time in their favorite games, we can tell that they are really addicted to that particular game. However, if someone plays his forvorite game for not so long, meaning he is aware that his time should be limited that particular game then we can't consider it as an addiction.
Well, I do not think that is completely right. Of course you would always spend much of your time on the things you love most, the amount of time spent on the game is not whats make it addiction it is the ability to control the time not to affect other things that makes it an addiction.
For instance if I do not have anything else to do and I decide to spend all my day playing my favorite game and having fun, I dont think I should be termed an addict to that game but a situation where I spend all day on that game at the expense of things that would better my life or just sacrifice more important things and I am not able to control myself to stop the game, that is when I should be termed an addict to the game.