I agree that violent video games are responsible for teenage violence,however this refers to the general population of teenagers that are avid gamers of violent video games.
According to an article from http://ithp.org/articles/violentvideogames.html
"97% of 12-17 year olds in the US played video games in 2008, thus fuelling an $11.7 billion domestic video game industry. In 2008, 10 of the top 20 best-selling video games in the US contained violence.Violent video games have been blamed for school shootings, increases in bullying, and violence towards women. Critics argue that these games desensitize players to violence, reward players for simulating violence, and teach children that violence is an acceptable way to resolve conflicts. " This shows the statistics to prove that there is a large amount of influence readily available to the teenage population in America. With such influence readily available, these avid gamers are exposed to violent media, these violent media often influence gamers and ause aggressive behavior in them.
The main objectives in these violent games is mainly to kill, and with successful killings, the gamers feel a sense of accomplishment. They then get addicted to this sense of accomplishment and implement violent behavior towards others to get a sense of accomplishment.
"Researchers at the Indiana University School of Medicine say that brain scans of kids who played a violent video game showed an increase in emotional arousal – and a corresponding decrease of activity in brain areas involved in self-control, inhibition and attention.(attached link) Mathews and his colleagues chose two action games to include in their research -- one violent the other not.
The first game was the high-octane but non-violent racing game “Need for Speed: Underground.” The other was the ultra-violent first-person shooter “Medal of Honor: Frontline.”
The team divided a group of 44 adolescents into two groups, and randomly assigned the kids to play one of the two games. Immediately after the play sessions, the children were given MRIs of their brains.
The scans showed a negative effect on the brains of the teens who played “Medal of Honor” for 30 minutes. That same effect was not present in the kids who played “Need for Speed.”
The only difference? Violent content.
What’s not clear is whether the activity picked up by the MRIs indicates a lingering — or worse, permanent — effect on the kids’ brains.
And it’s also not known what effect longer play times might have. The scope of this study was 30 minutes of play, and one brain scan per kid, although further research is in the works."
There has been scientific evidence to support my stand, the attached link clearly shows a large difference between the two MRI scans, this proves that violent video games have negative effects