"The Internet now plays a huge part in modern life, but its benefits are accompanied by a darker side," says study leader Dr. Catriona Morrison, of the Institute of Psychological Sciences at the University of Leeds.
The study reveals that the more time someone spends surfing the Internet, the less likely they are to be happy — with some hardcore web users demonstrating symptoms of both depression and addiction.
An online questionnaire was reportedly used to survey the levels of online dependency and rate of depression across 1,319 respondents who ranged from 16 to 51 years old.
"There was a high correspondence between the amount of time spent on the Internet and levels of depression," 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."
Out of the pool of respondents, Morrison’s team identified 18 individuals which they classified as Internet addicts who daily spent many hours online, and received depression scores that were more than five times higher than other users.
According to reports, those classified as addicts favored porn and gaming sites, along with social networking sites and online communities — and represented a younger audience, with an average age of 21. While representing only 1.2 percent of participants, this addiction rate is double the rate of gambling addiction in the general population.
"While many of us use the Internet to pay bills, shop and send emails, 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," Morrison said.
The "chicken and egg" question, according to researchers, is whether extended Internet use results in mental illness — or whether those already afflicted with (and perhaps more homebound by) mental health issues are naturally more attracted to the Internet than are members of the general population.
"Our research indicates that excessive Internet use is associated with depression, but what we don't know is which comes first — are depressed people drawn to the Internet or does the Internet cause depression?” Morrison concluded. “Now we need to investigate the nature of that relationship and consider the issue of causation."