Up to 70,000 people in Switzerland could be addicted to the Internet and another 110,000 are at risk of developing a fixation, a study has found.
A person considered a cyber addict uses the Internet on average 35 hours a week outside of work hours, according to the study, released by the Swiss Institute for the Prevention of Drug and Alcohol Problems on Monday.
The Institute says the symptoms and illnesses associated with excessive Internet users are comparable to those found in people with drug or alcoholic addictions.
Among the more common outcomes are difficult social relations, weakened scholastic or professional performance, irregular eating habits, bad posture, migraines and trouble with vision. When unable to spend as much time as they want online, addicts can also become anxious and even aggressive.
Online games and chat are the biggest causes of excessive Internet use, as well as the lure of websites with sexual or pornographic content.
"More and more people are using the Internet more regularly. We can assume that the more a product becomes available, the more a problem increases," Corine Kibora, a spokeswoman for the Institute, told swissinfo.
"For several years now experts have been debating how to deal with dependency on the Internet. Parents and educators have also been asking us more about this subject in recent months and years. But there is still a lack of research to show at what point it affects the population."
With Internet usage continuing to grow, more investigation is needed into the side effects, the Institute said.
According to figures gathered by the Federal Statistics Office, an estimated 2.5 per cent of the Swiss population is addicted to the Internet, and 3.7 per cent are at risk. The Swiss situation is believed to be comparable with the rest of Europe.
The study's authors say spending less than 35 hours a week online still constitutes an addiction. The Institute suggests that most people only cut down on usage after being come under pressure from friends and family.
The Institute has published suggestions to prevent the situation from worsening. Adults need to monitor usage by children and teenagers to make sure the Internet is used in moderation, it advises.
Technically, gaming websites could install time limits on access, while manufacturers could also help define healthy parameters, such as pop-up notices advising people to take screen breaks.
Users in general also need help in recognizing the limits of the Internet and should be given advice on how to manage their emotions and tips on the most economical and intelligent use of this medium, experts say.
The Institute hopes the study will focus attention and reflection on the issue.
"We are hoping for a reaction from game developers. Politically there is a need to act and to call for manufacturers to take on their responsibility.
"We hope to add fuel to the debate surrounding this question."
swissinfo, Jessica Dacey
64% of people over the age of 14 use the Internet daily or several times a week.
Men use the Internet more than women (73% versus 56%), while the younger generation, aged 14-29, are far more often online than the 50+ generation (84% and 41% respectively).
The data is based on a government survey on Internet use in Switzerland from 2006.
Currently, there is no generally accepted term to describe dependency on the Internet and excessive use can be referred to as "pathological use of the Internet", "Internet dependency", "cyber dependency" and "cyber addiction".
In 2000 the concept was fairly unknown, but has become more accepted today. So-called cyber addiction is a substance-free dependency and is not yet classified as a disorder or illness.
Characteristics include compulsive use of the Internet, loss of control over use, ever-increasing time spent online, interests limited to the Internet, manifesting symptoms such as anxiety when not online, and continued use despite negative side-effects. Not all need be shown at one time.
A Swiss study in 2001 found that people showing a dependency on the Internet spent an average of 35 hours online outside of their work.