Facebook can make users "lonely and angry" as they compare themselves to the seemingly perfect lives of others, a study says.
Denmark's Happiness Research Institute conducted an experiment on 1,095 people, who gave an average ranking of their current state of happiness of 7.6 out of ten.
Participants aged between 17 and 76 were questioned about how satisfied they felt, how active their social life was, how much they compared themselves to others, and how easy they found it to concentrate.
Half then stopped using Facebook for a week, while the rest continued as normal.
Those who did not log on said their happiness level rose to 8.12, while it did not change for the others. Those deprived of Facebook also took part in more real social activity.