A study at the University of Edinburgh Business School has found that the more groups of people in someone’s Facebook friends, the greater potential for stress. In particular, adding employers or parents resulted in the greatest increase in anxiety.

Stress arises when a user presents a version of themself on Facebook that is unacceptable to some of their online “friends,” such as posts displaying behavior such as swearing, recklessness, drinking and smoking.

As older people join the site, this has become an increasing problem because their expectations may be very different from those of younger users. Some 55 per cent of parents follow their children on Facebook. And more than half of employers claim not to have hired someone based on their Facebook page.

The researchers found that on average, people are Facebook friends with seven different social circles. The most common group was friends known offline (97 per cent added them as friends online), followed by extended family (81 per cent), siblings (80 per cent), friends of friends (69 per cent), and colleagues (65 per cent).

The report also discovered that more people are Facebook friends with their former partners than with their current relationship partner. Only 56 per cent of users were friends with their boyfriend, girlfriend or spouse online, compared with 64 per cent of exes.

The report surveyed more than 300 people on Facebook, mostly students, with an average age of 21.

It also discovered that only one third use the listing privacy setting on their Facebook profile, which can be used to control the information seen by different types of friends.