OBSESSIVE use of the internet could create a mental-health epidemic, with up to 10 per cent of adolescents at risk, a Sydney academic warns.

World studies have documented dangerous levels of "internet addiction" – computer use that interferes with daily lives – says Lawrence Lam, a behavioural epidemiologist at the University of Sydney and the Children's Hospital at Westmead.

In Greece and the US, studies found 8 per cent of adolescents could be classified as computer addicts. In China, where Dr Lam helped conducted recent research, the level of addictive computer use was 14 per cent. "I would say in Australia we would be following the same trend," he said.

Dr Lam said researchers were yet to agree on whether to label the problem as an addiction or a mental-health problem but it was expected the condition could be added to the next edition of the key reference book for mental-health professionals, the Diagnostic and Statistical Manual of Mental Disorders.

He said people who played online role-playing games such as World of Warcraft, were especially prone to the condition, which he defined as an “uncontrollable and damaging use of the internet”.