Children and teens with ADHD, or who are depressed or hostile, may be prone to becoming addicted to using the internet, a new study suggests.

Internet addiction is not an official diagnosis by the American Psychiatric Association, but some experts consider it a potential problem if it interferes with everyday life, such as harming school performance, family relationships or someone's emotional state.

Signs include:

• Spending more time on the internet than intended.
• Inability to cut back on usage.
• Symptoms of withdrawal such as anxiety or boredom after a few days of refraining from going online.

Researchers in Taiwan looked at the potential link between internet addiction and psychiatric symptoms such as attention-deficit/hyperactivity disorder (ADHD), social phobia and hostility in 2,293 boys and girls from 10 junior high schools in southern Taiwan.

The students' psychiatric symptoms were surveyed using self-reported questionnaires, and internet addiction was assessed when the study began and six, 12 and 24 months later. Scores ranged from 26 to 104 on the researchers' scale, with a score of 64 or higher considered internet addiction.

'Our intention in raising this concern is not to be alarmist but rather to alert pediatricians to what might become a major public health problem for the United States in the 21st century.'— Dr. Dimitri Christakis and Dr. Megan Moreno

Of all participants, 233 or 10.8 per cent were classified as having internet addiction and 1,929 (89.2 percent) were classified as not having an internet addiction, the team reported in the October issue of the Archives of Pediatrics & Adolescent Medicine.

"These results suggest that ADHD, hostility, depression and social phobia should be detected early on and intervention carried out to prevent internet addiction in adolescents," Dr. Chih-Hung Ko of Kaohsiung Medical University Hospital and colleagues concluded.

Previous studies suggest that 1.4 per cent to 17.9 per cent of adolescents are addicted to the internet, with percentages higher in Eastern nations than in Western nations, the researchers noted.

In girls but not boys, depression and social phobia were linked to internet addiction problems.

Boys were at higher risk than girls, and those who used the internet for more than 20 hours a week were also at higher risk, the study found.

Adults over-check email

"Part of the failure to recognize this potential 21st-century epidemic is the simple fact that many of us, BlackBerry in hand, check email more than we would like," Dr. Dimitri Christakis of the Center for Child Health, Behavior and Development in Seattle, and Dr. Megan Moreno, wrote in an accompanying editorial.

"The inherent difficulties in defining internet addiction and our own need for rectification should not prevent us from recognizing an emerging epidemic."

If all children who are at risk are exposed enough to become addicted, the prevalence of internet addiction in Western countries could approach that of Eastern countries and rank as one of the most common chronic diseases of childhood, the pair said.

"Our intention in raising this concern is not to be alarmist but rather to alert pediatricians to what might become a major public health problem for the United States in the 21st century."

Online safety experts recommend monitoring children and teens' internet use and suggest putting home computers in a public place such as a hallway or family, instead of allowing children to go online in private.

The internet addiction study was funded by the National Science Council of Taiwan.