Teen Internet users who are among those spending the greatest or the least amount of time online may face an increased risk of health problems including depression, a new study finds.

The researchers were surprised by the results they expected those who used the Internet very little to be in good health. Earlier work showed heavy Internet use is associated with mental health problems, they said, but the new study is one of the first to examine the health effects of low Internet use.

The findings suggest adults should accept reasonable amounts of Internet use , and find ways to help teens use it appropriately.

"Many adults...tend to demonize the use of Internet," said study researcher Dr. Pierre-André Michaud, of the Institute of Social and Preventive Medicine in Switzerland. "Because they don't master the Internet as well as their children."

"We should think in the future of improving the way the school and society responds to the challenge of assisting young people in making the best use of Internet," Michaud said.

Teens online

Michaud and his colleagues examined information from a health and behavior survey taken by 7,211 adolescents, ages 16 to 20, in Switzerland in 2002. The participants 2,205 girls and 3,906 boys were all students, though about two-thirds were enrolled in a vocational school and attended only one or two classes per week.

The researchers grouped the participants into four categories: high Internet users, who were online for two or more hours a day, regular Internet users, who were online several days per week but for less than two hours per day, occasional Internet users, who went online once a week or less, and non-Internet users, who had not been online in the past month.

High Internet users of both genders had a higher risk of depression than regular Internet users. Boys in this group were also at risk of being overweight, and girls were at risk for not getting enough sleep.

Non-Internet users of both genders also had a higher risk of high depression scores than regular Internet users. Those who use the Internet rarely or never may be disconnected from their peers, and thus more prone to depression, Michaud said.

"It's important during adolescence for most youngsters to feel part of the group, to socialize," Michaud said. "Those who don't at all maybe feel isolated, and maybe tend to be depressed more easily."

However, the researchers did not collect data on how the teens and young adults spent their time online, so they can't say whether the teens used the Internet to socialize or for other reasons, such as school work, he said.

When is not going online a problem?

The study is consistent with other research suggesting that "more and more, Internet use is a part of young people's social landscape," said Elisheva Gross, a psychology researcher at the University of California, Los Angeles, who has studied Internet use and well-being among adolescents but was not involved in the new study.

Normal amounts of use are to be expected, and are not a problem, Gross said, but she noted that parents should not necessarily worry if their child does not spend time online .

"I wouldn't take this as a sign that they should go force their child to get online," Gross said. "I would instead consider the whole person, the whole child, the whole teenager, and say what's going on with this child, are there other things that would suggest he or she is disconnected from their peers, from engagement with the word around them? It might be a symptom of a larger problem."

The study was published online Jan. 17 in the journal Pediatrics.

Pass it on: Both high internet use and none at all were associated with health problems in teens and young adults.

Follow MyHealthNewsDaily staff writer Rachael Rettner on Twitter @Rachael_MHND.