Violent video games do not increase the risk of antisocial behaviour among teenagers with mental health conditions such as depression, a new study indicates.

Many people believe that violent video games fuel aggression and other behavioural problems, such as bullying and physical fighting, in young people, particularly those with pre-existing mental health issues. US scientists decided to look into this further.

They monitored almost 380 children with an average age of 13. All of the children had shown symptoms of depression or ADHD (attention deficit hyperactivity disorder).

The scientists found no link between the playing of violent video games, such as Grand Theft Auto and Halo, and subsequent bad behaviour among the teens. In fact, in some instances, the games appeared to have a very small calming effect on the young people and actually reduced aggressive tendencies.

"We found no evidence that violent video games increase bullying or delinquent behavior among vulnerable youth with clinically elevated mental health symptoms," the scientists said.

Details of these findings are published in the Journal of Youth and Adolescence.