Psychologists have confirmed that playing violent video games is linked to aggressive and callous behaviour.
A review of almost a decade of studies found that exposure to violent video games was a "risk factor" for increased aggression.
But the same team of experts said there was insufficient evidence to conclude that the influence of games such as Call Of Duty and Grand Theft Auto led to criminal acts.
The findings have prompted a call for more parental control over violent scenes in video games from the American Psychological Association (APA).
"The research demonstrates a consistent relation between violent video game use and increases in aggressive behaviour, aggressive cognitions and aggressive affect, and decreases in pro-social behaviour, empathy and sensitivity to aggression," a report from the APA task force on violent media concludes.