The idea that a simple video game could so completely upend a teenager's life is the kind of thing that most parents, at least until recently, would not have taken seriously. After all, shoot-'em-up computer simulations don't raise the same sort of red flags for parents as drugs, alcohol, or delinquent friends. But there is growing concern, even in medical and scientific quarters, that there may be a link between video games like Call of Duty and obsessive, even addictive, behaviour. For some teens, this might lead to minor problems like slipping grades and a loss of interest in other hobbies. But there are an increasing number of reports of far more tragic outcomes. Earlier this year, for instance, a British boy committed suicide after his father took away a Wii game. In a youth culture where so much social interaction has moved online, the deep ties young people can form to games and other computer pastimes could, some experts say, be a recipe for disaster. How do you tell when that line has been crossed? Today, it's the kids who don't play video games that stand out. According to a survey released by the Pew Internet & American Life Project last month, 97 per cent of U.S. teens aged 12 to 17 say they regularly "game," whether on a console system, computer, or handheld device. In Brandon's school alone 25 other students regularly play Call of Duty on the same online system he used. And the business continues to grow exponentially. In 2007, software sales reached US$9.5 billion, with nine games sold every second, according to the Entertainment Software Association.

But measures of how many people — not just teens, but adults and children — might be considered "addicted" to their games are much harder to come by. A widely cited 2007 survey by Harris Interactive claimed that 8.5 per cent of gamers aged 8 to 18 were "pathologically addicted" to their onscreen pastime. A larger U.K. study in 2006, of gamers of all ages, concluded that 12 per cent of the 7,000 respondents were unable to live without their games, experiencing "craving, withdrawal symptoms, loss of control and other negative consequences," usually associated with addicts.

Dr. Jerald J. Block, a Portland, Ore., psychiatrist who specializes in computer compulsions, says Internet addiction — whether to porn, games or social networking sites — is a real and growing phenomenon. "For some people, the Internet and games are an escape. It's a place where they can take anger, frustration and sexual tension and channel it. It can swallow up 30 or 40 hours a week, or more, and stop them from feeling bored and restless." Block says addiction problems manifest themselves more frequently among adult gamers and Internet users, if only because few grown-ups can avoid the work and family consequences that stem from spending most of their waking time at the computer.

But what sets the broad category of Net addiction apart from other compulsive behaviours, says Block, is how difficult it is to diagnose and treat. Many patients have difficulty even confronting the issue because of their shame (more so for games, because of their "childish" association, than even porn, notes the doctor). And the addiction is frequently complicated by other underlying problems like depression, attention deficit disorder, or anxiety. By the time patients seek treatment, the computer has often become the primary relationship in their life, and the process of untangling the person from the machine can be fraught. Block advises families to avoid abruptly "unplugging" patients from their games or Internet use because of the danger of backlash. "It's an explosive situation. You should expect a very, very angry outburst that may last several days to weeks," he says. In an article in the American Journal of Forensic Psychiatry last year, Block argued that a significant contributing factor in the 1999 Columbine High School massacre was a decision by the parents of Eric Harris and Dylan Klebold to cut them off from their beloved Doom computer game. The rupture, he says, motivated the pair to move from a world of homicidal fantasy to real-life murder.

Thankfully, such extreme examples are few and far between. A more typical scenario sees addicted gamers directing their anger inwards at themselves. Brad Dorrance, a 40-year-old "ex-gamer" from London, Ont., knows that extreme type of despair all too well. His entire adult life has been defined by his computer use. On the eve of his 1999 marriage, he stayed up until 4:30 a.m., racking up a new high score on Quake 2. In 2001, on stress-leave from his job, he discovered online games, and the problem became even worse. Within months, he was playing up to 12 hours a day, and efforts to retrain and find a new job fell by the wayside. He became obsessed with the newest games and latest technology, running up $23,000 in credit card debts, undermining his wife's efforts to keep the family finances afloat. Finally after years of denial, the guilt overwhelmed him. Last December, Dorrance tried to commit suicide with an overdose of sleeping pills and ended up in a local psychiatric facility.