People who spend large amounts of time on the internet may be more likely to suffer from depression, UK scientists have said.
Psychologists at the University of Leeds found that some people use online chat rooms and social networking sites at the expense of engaging in real-life social interaction, and that this may have a harmful effect on their mental health.
The team studied the internet use of 1,319 people, aged 16 to 51, along with their levels of depression.
They found that 1.2 per cent of participants - usually young people - were addicted to the internet and that these users were more likely to suffer from moderate to severe depression.
Dr Catriona Morrison, lead author of the study in the journal Psychopathology, warned that replacing normal social interaction with internet sites 'might be linked to psychological disorders like depression and addiction'.
'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?' Dr Morrison explained.
'What is clear is that for a small subset of people, excessive use of the internet could be a warning signal for depressive tendencies.'
The symptoms of depression depend on the individual but may include sleep problems, lethargy, despair, lack of appetite, tearfulness, irritability and poor concentration.