About 9.72 percent of Chinese netizens between the ages of 13 and 30 suffer Internet addiction, a survey revealed on Friday.

The survey defines an Internet-addicted as one whose life, career and interpersonal relations are harmed by Internet use, said the report issued by the China Youth Association for Network Development (CYAND).

"Anyone fitting in one of the three criteria we set is considered Internet-addicted: First, a person feels happier or more self-fulfilled online than in real world. Second, a person feels upset, depressed, or panicked when being cut off from the Internet for any reason. Third, a person lies to the family members about how long he spends online," the report said.

China reported 210 million Internet users at the end of 2007 and is set to become the world's largest at the beginning of this year, according to the China Internet Network Information Center (CINIC), the main Internet watchdog.

Net users between 18 and 30 accounted for 49.9 percent of the total users. Although the CINIC did not give the figure of those below 18. Teenagers and youths have obviously taken up half of the total number of net users.

A clear gender difference was found among the addicted in the survey. About 13.29 percent of young male netizens are addicted, 7.18 percentage points higher than that among female counterparts.

Among the Internet-addicted, 68.64 percent are male and 31.36 percent are female, the report said.

About 11.39 percent of the young net users between 18 and 23 are addicted to the Internet, the highest compared with those between 13 and 17 and those between 24 and 30.

The survey also found that more Internet-addicted youths suffer frustration in interpersonal relations than those not.

It showed that 21.59 percent of the addicted do not get along well with family members, compared with 9.94 percent of those not; 17.49 percent of the addicted do not have good friendships, compared with 9.01 percent of those not.

Lots of odd stories about Internet addiction hit headlines in recent years.

A boy named Zhang Fei from the southwest Sichuan Province shocked the country last year. He has been enrolled in China's best universities twice and dropped out twice because of being addicted to online games and failing in most of the exams.

Zhang Fei was admitted to the top-ranking Peking University in 2003 and dropped out a year later because he failed seven of his 18 subjects. He went back to high school and took the national college entrance exam in 2005, managing to enter the equally prestigious Tsinghua University, but he left that university for the same reason.

"I just feel vacuous and turn to online games to kill time. Somehow I just can't stop," Zhang was quoted by the Central China TV Station.

His ex-classmates described him as anti-social and eccentric. Zhang himself admitted that he was loathed himself and often felt reluctant to communicate with others.

The boy has again performed well in the 2007 college entrance exam and was enrolled at Tsinghua University in July while receiving psychological therapy.

The survey found that 40.77 percent of the addicted netizens play online games, 13 percentage points higher than those not.

"We shall be careful about this. Usually addiction to online games leads to serious Internet addiction," said Hao Xianghong, secretary-general of the association.

The association sent out 12,000 questionnaires in schools, Internet cafes and other public places in 12 Chinese cities, including the biggest Beijing, Shanghai, Chongqing and Guangzhou in September last year and received 11,023 responses.

It also did online surveys at three leading websites getting 10,363 responses.