According to researchers in the USA, violent video games increase agression among teenagers and may even be worse than watching violent TV shows or films because video games are interactive.

Craig Anderson of Iowa State University of Science & Technology conducted two separate studies into the link. In the first, a study of 227 college students revealed that the more violent the video games were, the more aggressive became the students' behaviour.

In another survey, 210 college students were asked to play either a violent or non-violent game. The winners of the more violent games were found to be more likely to 'punish' their opponents with a blasted noise than those who played non-violent games.