About 9.7 percent of Chinese netizen between 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, he feels upset, depressed, or panicked when being cut off from the Internet for any reason. Third, he 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.

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.