Computer games and in particular violent games have come under stick for promoting violence and or criminal/antisocial activities (and I will keep this short), I disagree they promote violence and there are no actually conclusive studies that support this:Although such studies are fairly subject to art and bias anyway but meh...
1) if you are already the sort of person who likes violence then you will gravitate towards violent situations real world or not.
2) if you are the sort of person who uses games as an escape and has no real violent tendencies or will to explore violent activities, you will not be harmed by exploring such violence, on the contrary it is healthy to explore the violent side of your nature, we all have one it's why we are the dominant species on the planet, but that correlation does not equal causation any more than it does in the sub group of those who play violent games who then go on to do violent things or x in the real world.
I believe if you are already disturbed then you will gravitate towards violence in the real world or in another medium to "get your fix" you wont become violent because you played violent games any more than you will become a drug addict because you saw someone taking drugs.