A study of people who play online computer games has found that 12% have signs of addiction.
One in nine people surveyed showed signs of addiction
Professor Mark Griffiths, of Nottingham Trent University, revealed the results of a survey of 7,000 online gamers in a British Science Museum lecture.
He said the main aim of the study was to investigate the addictive potential of gaming.
Addictive signs included craving, withdrawal symptoms, loss of control and other negative consequences.
The majority, 94%, of those who took part in the study were men, with an average age of 21. One in nine fulfilled criteria of addiction.
"Addicted" gamers played for significantly longer periods of time each day than those who were not addicted.
Professor Griffiths said: "Although these gamers show some signs of addiction, our results do not conclusively show that the gamers are genuinely addicted.
"Many gamers play excessively and display few negative consequences.
"However, the 24-hour a day, never-ending online games may provide a potentially addictive medium for those with a predisposition for excessive game playing."
His research will be published in a forthcoming issue of the US journal CyberPsychology and Behaviour.