The BBC's Emma Simpson: We don't have the time or energy to keep up with friends

Research carried out in the UK has identified a "Friends Syndrome" - named after the hit US comedy about a group of flat-sharing 20-somethings.

The survey finds that young people have less, but more intense, friendships because they do not have the time or energy in their busy schedule to maintain a wide circle of friends.

A typical 30-something has only three "close" friends - half the number of the previous generation - and up to 50 "unbonded" or more casual companions.

Findings are 'depressing'

Young people are also more willing to dump casual friends when circumstances change.

The research was conducted in the UK by Dr Geoff Collee of NYC University in New York.

Sociologist Laurie Taylor: People are genuinely short of friends

He said he was "rather depressed" by the results, which suggest that people could be lonelier than past generations.

Psychologist Dorothy Rowe, who is researching friendship for a book she is writing on friends and enemies, said the pattern outlined in the research exists, but is not necessarily a bad thing.

She said: "Most people have one or two friends that they have had for a long time who they feel close to and can talk to and other people whose company they enjoy but they don't confide in so much.

"Usually what brings people together is when they have shared disasters or tragedies together.

"But there are also a lot of people who you only meet in social occasions and where you don't know what they are struggling with underneath.