© UbisoftGames such as Assassin's Creed feature a huge amount of physical violence - and MRI scans demonstrate that playing such games DOES have an effect on the brain.
But activists such as Oxford Professor Baroness Greenfield have often presented little science to back up their allegations.
However, extensive research into the subject has now provided worrying results that support her claims.
'Screen technologies cause high arousal which in turn activates the brain system's underlying addiction,' the neurologist said last month in an attack that accused games of causing 'dementia' in children.
'This results in the attraction of yet more screen-based activity.'
And now the first genuinely scientific attempt to analyse the emotive subject has thrown up astonishing results that suggest she is right.
Differences in brain activity between young men who played violent games and ones who didn't were visible in a randomly assigned sample in just one week.
