Surfing the Web could be hazardous to your mental health, according to a new study.

The study, conducted by British scientists, indicated that the longer people spent online, the less likely they were to be happy.

However, the study did not indicate whether using the Internet causes mental health problems, or if individuals already diagnosed with mental health problems are more likely to be attracted to extended Internet use.??Scientists used an online questionnaire to determine levels of Internet dependency and depression in 1,319 individuals from ages 16 to 51.

“The Internet now plays a huge part in modern life, but its benefits are accompanied by a darker side,” the study’s leader, Dr. Catriona Morrison of the Institute of Psychological Sciences at the University of Leeds, said in a press release.

Morrison’s team tested a group of 18 individuals who were classified as “Internet addicted.” Their average depression scores were more than five times higher than those of non-addicted users, and they were more likely to be moderately or severely depressed, according to the release.

“There was a high correspondence between the amount of time spent on the Internet and levels of depression,” Morrison said. “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.”??The average age of the addicts was 21, and those users spent significantly more time browsing porn sites, gaming sites and online communities. ??“While many of us use the Internet to pay bills, shop and send e-mails, 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 added.