Always envious? Got a non-existent social life and struggle to concentrate? All this might be down to Facebook if you believe a study showing those who go a week without using the social network feel happier than others.

Carried out by the Happiness Research Institute, the study involved a sample of 1,095 people in Denmark who were divided into two groups, half of whom continued using Facebook while the others stopped.

"We focused on Facebook because it is the social media that most people use across age groups," Meik Wiking, HRI's chief executive told AFP Tuesday in Copenhagen, the Danish capital.

After a week, those people who hadn't been on Facebook said they were more satisfied with their lives, with 88 percent of them describing themselves as "happy" compared with 81 percent from the second group.

Some 84 percent said they appreciated their lives compared with 75 percent in the other group, and only 12 percent described themselves as dissatisfied, compared with 20 percent among those who continued using Facebook.

At the end of the experiment, the abstainers reported having a richer social life and fewer difficulties in concentrating, while the others reported no such change.

"Instead of focusing on what we actually need, we have an unfortunate tendency to focus on what other people have," the authors of the study wrote.

In other words, Facebook users are 39 percent more likely to feel less happy than non-users.