Is there a real link between violent video games and violent teenagers, Ronan McGreevyasks.
Teenager Stefan Pakeerah died a terrible death in a park in Leicester three years ago. He was hit so hard over the head with a hammer that his skull was fractured in several places. He had multiple stab wounds to his neck and torso.
His murderer, Warren Leblanc (17), had lured him to the park on the promise that they were going to meet some girls. A misfit with a violent past, the victim's mother described him as "inherently evil".
The case made headlines around the world not just because of the shockingly violent nature of the crime, but because of an allegation that Leblanc had been motivated by the video game Manhunt.
Stefan's mother, Giselle Pakeerah, said the manner in which Leblanc carried out the killing with a claw hammer and knife was similar to Manhunt, a game which Leblanc was obsessed with, according to his friends.
The police discounted such a motivation, but there was little doubt the initial furore was one of the reasons behind the banning of Manhunt 2 by the British Board of Film Classification (BBFC), only the second such game to be banned.
Most video games are, to a greater or lesser extent, violent, but Manhunt 2 had an "unrelenting focus on stalking and brutal slaying", the BBFC said last month.
The Irish Film Censor's Office (IFCO) followed suit saying the "the level of gross, unrelenting and gratuitous violence is unacceptable".
Film censor John Kelleher says the IFCO is prepared to ban other video games if they are similarly violent. "Manhunt 2 crossed a line and this implies that there is a line to be crossed," he says.
Audrey Conlon, a former censor who is now the chairwoman of the Internet Advisory Board, says a stand had to be taken by the current censor. "In my experience, 10 or 15 years ago, video games were mostly for children.
"Then they became a bit more adult and it has been an upward trajectory from there whereby these games are getting more and more violent."
She urges parents to log on to the Pan European Game Initiative (PEGI) website if they want to get a rating for a game their child might want to buy.
Video games get a bad press. There is hardly anybody in a position of authority who will defend them, although the millions of people, mostly men, who play them remain as impervious as ever to the criticism.
The term "PlayStation generation" is, in some people's minds, synonymous with childhood obesity, anti-social behaviour and general indolence.
Quite the most serious allegation, though, is that violent games actually encourage violent behaviour in young people who would otherwise not indulge in such activity.
Clinical psychologist and Irish Times columnist Marie Murray has no doubt that violent video games have had a detrimental effect on some vulnerable children and the video games industry is in collective denial about it.
"I did not start with the presumption that video games cause young people to be violent," she says. "It was while I was working with adolescents that they made me aware of the levels of violence in these games and why they find them extremely attractive.
"These games have a number of serious consequences. They create a desensitisation and normalisation of violence at a young age. It's not a question of censorship, it's a question of child protection."
Changing video games into a benign influence on young people is the goal of an initiative between Dr John Sharry, a psychotherapist at the Mater hospital, working with the Therapeutic Technology Research Group in Trinity College Dublin, with the aid of financial support from Enterprise Ireland.
They are developing a three- dimensional video game using the metaphor of a detective to get children who are attending mental health services to reveal more about themselves than they would through conventional therapies.
"It's using a gaming metaphor as a way of engaging young people," he says. "Sometimes it's very hard to get young people to articulate how they are feeling.
"Not all video games are bad just as not all television is bad. If you look at people who have been excessively violent, there is often an interest in violent media in general whether it be violent television, movie or video games," he says.
"Whether it causes it or not is not easy to determine, but there is certainly an association between the two things."
Several academic studies have been done in the US which suggest that there is a direct causal link between violent video games and violent teenagers. A study by a research team from the University of Missouri-Columbia, which monitored brain activity in video game players, found the games trigger a mechanism in the brain that makes people more likely to behave aggressively.
There is, however, no medical consensus on the issue. It is a link that is difficult to prove one way or another, given all the different factors that can cause aggression in young people.
An often-cited study by those who claim that video games are unfairly blamed for violent behaviour was conducted by the US Secret Services in 2002. It examined people who had carried out school shootings. The study found that only 12 per cent of those involved were attracted to video games and much more were inspired by violent movies and books.
Two years ago researchers in the US and Singapore monitored levels of aggression in a group who played the violent video game Asheron's Call 2 for 56 hours and those who didn't and found no appreciable difference between the two groups.
A surprising advocate of the ban on Manhunt 2 is one of the biggest critics of those who claim that violent video games affect behaviour.
Dr Guy Cumberbatch, director of the Communications Research Group in the UK, says the ban is correct on the basis of "taste and decency". "Video games are continually pushing out the boundaries as far as they can go. It's right to say enough is enough," he says.
The furore over Manhunt 2 has left him unmoved, though, on the central issue of whether there is a link between violent games and violent behaviour. He says blaming violent video games is like blaming Doc Marten boots for skinhead violence.
"All the evidence that has been produced is not relevant in a scientific sense. You have to find the pathology somewhere else other than that they have exposed themselves to these games. Video games can be a symptom rather than a cause of a child's obsession with violence."
The banning of Manhunt 2 is unlikely to have any effect on the gaming community in Ireland other than to lead many of them to try to import it through the internet.
Darragh Verschoyle, the editor of the online magazine Gaming Ireland, says serious gamers will avoid Manhunt 2 as they avoided the original Manhunt because it is a very average game though others will seek it out just for the kudos of owning something that is banned.
"Personally, I don't think it should have been banned. I've played Manhunt 2 and I've seen the film Hostel 2 and violence-wise, there's nothing between them, but Hostel 2 was never going to be banned," he says.
"Manhunt 2 is certainly very violent. I think it was singled out because its publisher Rockstar was also responsible for the original Manhunt and Grand Theft Auto. I've seen a lot worse. There's not much difference between it and games like Resident Evil, Doom or Prey where part of the game is to shoot demonic kids."