Psychologists have found evidence of a strong link between time spent surfing the Web and depression. The longer people spend on the Internet, the less likely they are to be happy, according to researchers.
An online questionnaire was used to assess levels of Internet dependency and depression in 1,319 individuals ranging in age from 16 to 51. In general, the longer people spent online the more depressed they tended to be, the scientists found in a study published in Psychopathology Journal.
A small group of the worst-affected individuals were both depressed and addicted, a study by the Institute of Psychological Sciences at the University of Leeds found. But it is not clear whether using the Internet causes mental health problems, or whether people with mental health problems are drawn to the Internet.
More work is needed to answer this "chicken and egg" question, study leader Catriona Morrison said.
"There was a high correspondence between the amount of time spent on the internet and levels of depression," said Dr Morrison. "If you look at how dependent people feel they are on the Internet that is likely to correspond with how happy or sad they feel."
Her team identified a small group of 18 hardcore Internet users who spent many hours online each day and were classed as "Internet addicted." Their average depression score was more than five times higher than that of non-addicted users, and they were more likely to be moderately or severely depressed.
The addicts spent proportionately more time browsing porn sites, gaming sites and online communities. They also tended to be young, having an average age of 21.
"While many of us use the Internet to pay bills, shop and send e-mail, there is a small subset of the population who find it hard to control how much time they spend online, to the point where it interferes with their daily activities," said Dr Morrison.
"This study reinforces the public speculation that over-engaging in Web sites that serve to replace normal social function might be linked to psychological disorders like depression and addiction.
"We now need to consider the wider societal implications of this relationship and establish clearly the effects of excessive Internet use on mental health."
Incidents such as the spate of suicides among teenagers in the Welsh town of Bridgend in 2008 have led to questions about the psychological dangers of social networking sites.
Some experts are worried about their potential for fueling depressive thoughts in vulnerable teenagers.
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