People that spend a significant time online are far more likely to suffer symptoms of depression, says a team of psychologists at the University of Leeds.
When people begin to substitute real-life, face-to-face interaction with online conversations in chatrooms and on social networking sites like Facebook and Twitter, there's often "a serious impact on [their] mental health," the pyschologists found following a study.
"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," said researcher Dr Catriona Morrison from the University of Leeds.
"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?"
This study echoes one published last August that came to a similar conclusion.
That study, conducted by the Centers for Disease Control and Prevention, found that the average online gamer is not a teenager, but is actually a 35-year-old overweight, aggressive, introverted - and often depressed - man.
The study also found that when children and teenagers become game players, many tend to follow a trend toward physical inactivity and corresponding health problems that extend into adulthood.
The University of Leeds research found that people considered to be 'internet addicts' spent far more time than average users browsing sexual websites, online gaming sites and online communities.
And internet addicts showed a 'higher incidence' of moderate to severe depression, though the study did not report on the exact percentage of addicts that showed depressive symptoms.
For this study, researchers interviewed 1,319 people between the ages of 16 and 51 - 1.2 percent of whom were found to be internet addicts.
That number is higher than the 0.6 percent of Brits who are considered to be gambling addicts, the researchers noted.