Doctor claims video games 'don't lead to violence'
Psychologists in the US are warning that people who are depressed, lonely or angry could turn hostile after playing violent video games.
But the study says for the majority the games have no negative effect.
The American Psychology Association says they can also help those suffering from things like diabetes or asthma.
Doctor John Ryder, a psychologist in New York, said: "Usually violence begets violence, not watching it on TV or play-acting in a video game."
"There is no reason to assume that doing that will make someone more violent. That is just ridiculous."
Some doctors claim there's too much focus on the negative affects of violent gaming, and in some cases, say games can actually help children combat behavioural problems and illnesses.
Dr John Ryder, who's worked with patients suffering from gaming addiction, agrees with that view.
He thinks violent behaviour can develop when children are raised in an aggressive environment.
The debate about whether video games trigger violence has been going on for years with no definite conclusion.
There are psychologists who argue both for and against it.
One theory is that violent games affect those who are mentally vulnerable and suffer from things like depression and mood swings.
'It's pretty bad'
Newsbeat's spoken to a 21-year-old gaming addict who realised that playing violent games every day was having a psychological affect.
Doctor Patrick Markey, professor at Villanova University in Pennsylvania, claims an individual's personality determines whether they will be affected.
He conducted a study involving more than 100 teenagers.
Some played violent video games and others played non-violent ones.
He assessed their mood and what he calls their hostility and concluded: "Those who are negatively affected have pre-existing dispositions, which make them susceptible to such violent media."
A 21-year-old gaming addict (who didn't want to give his name) has told Newsbeat that playing violent video games for hours every day was having a psychological effect.
He reckons the games have an impact no matter what type of personality a person has.
He said: "You get to a point where shooting from a sniper range becomes boring and you want to play through the whole game only killing everybody with your knife.
"Players can come to the point where they see this as an alternative to real life interaction and if this is their other world, it's pretty bad."
Dr Cheryl Olsen, from Harvard Medical School, conducted a study on youth and video games with a focus on how parents can use them to nurture and teach their children.
She said: "Given that the typical young teenage boy plays violent games, and that the youth crime rate has gone down rather than up, it makes sense that these games are meeting needs.
"Such as testing out different identities, healthy competition, building social skills and dealing with difficult emotions such as anger and fear."
But not everyone agrees.
One gamer told Newsbeat: "They're bad news. Anything that shows stabbing, shooting, kinds of killing, can't teach anything but that."
Proving a link between video gaming and rising crime rates is also difficult.
The US Bureau of Justice's statistics says there's been a decrease in overall crime in America over the last 20 years.