Psychologists have found a link between playing violent video games and aggressive behaviour:
Violent video game play makes more aggressive kids, study shows
I think that this study is backward, it is very well possible that as people become more violent that they enjoy violent video games more.
another possibility is that these studies were done on children going through puberty, which naturally causes violence and detachment.
The violence could also come from the desensitization that occurs because of the news, causing people to not know much else than violence.
I personally believe that violent video games are good for society and makes it safer I know after a long stressful day, I like to sit down and play Medal of Honor, or Grand theft auto because I know that I can do whatever I would like in the game because it is just a game.
For example many of the famous serial killers of the 80's and 90's (Zodiac killer, Ted bundy, Unibomber) did not have these games to play, so they could not get their rush, hence the hedonistic category of serial killers (
Serial killer - Wikipedia). Could it be possible that if a potential hedonistic serial killer had violent video games they might not ever kill because they can get a rush from games.
Also, a majority of the time, violence (especially gang violence) occurs in poverty stricken areas, where many people do not have the money to buy new game systems or games. meaning some of the most violent of people do not have these games to effect them.
Lastly, using myself as an example. I have been playing violent video games such as grand theft auto, medal of honor, or even Legends of Zelda if you really want to get down to the roots, since about the age of 7. and now, almost 11 years later I am a good student who even when under achieving passes all of my classes with acceptable grades (A's and b's). I have never drank, nor have I ever done drugs, I have never never been in a fight (save the 3 years of martial arts I took). I take college level classes and I am just going into my senior year of high school. I would continue but I do not like talking about myself.