Come on people - this has been studied to death and yes, violent video games "can" have a negative impact on the player. Violent video games are associated with higher levels of aggressive behavior and thought. They are also associated with a decrease in prosocial behavior and concern/empathy for others. This is more so with video games than with TV, even, because the video games are interactive and often require the player to identify with their character.

Look at it this way - if you guys watch a porno flick are you aroused? Do 15-year-old girls who read Cosmo begin to dress and act in a manner past their age? Do commercials for snack foods make you want to get a snack? Does working for a bad boss make you fantasize that he steps out onto the street in front of a bus? There is a cause and effect to most things we do, after all.

But, the video games is only part of the story. If you are a stable person it will have merely a little effect. If the person is less emotionally stable, it can have a huge effect. Look at gun owners - 90% are fine. Those other 10% draw their guns in rage when somebody cuts them off in traffic, use their guns to intimidate others, use them for crimes, accidentally shoot their children sneaking back into the house at 2:00 a.m., go into a school and shoot little kindergarteners, etc. It's all relative to the individual - that person's upbringing, environment, and mental health.