Britain's teenagers are among the most badly behaved in Europe, a study by a think-tank has suggested.
British youngsters have a reputation for heavy drinking
On every indicator of bad behaviour - drugs, drink, violence, promiscuity - the UK was at or near the top, said the Institute for Public Policy Research.
The institute looked at the results of a number of studies of adolescents conducted in recent years.
The researchers believe the country's record can be explained by a collapse in family and community life in the UK.
Measured against German, French and Italian youngsters, British 15-year-olds are drunk more often and involved in more fights, and a higher proportion have had sex.
The institute says young Britons are marked out by how they spend their free time.
In England, 45% of 15-year-old boys spend most evenings out with their friends, and in Scotland the figure is 59%.
In France just 17% of boys spend their time in the same way.
On the other hand, European teenagers tend to sit down for meals with their parents far more often.
Some 93% of Italian teenagers eat regularly with their families; in the UK just 64% of 15-year-olds do the same.
Nick Pearce, from IPPR, said these figures pointed to an "increasing disconnect" between children and adults.
He said youngsters were learning how to behave from one another instead of from adults.
"Because they don't have that structured interaction with adults, it damages their life chances," he said.
"They are not learning how to behave - how to get on in life - as they need to."
The researchers concluded that the lack of adult interaction has left British teenagers increasingly vulnerable to failure.
One study looked at by the IPPR suggested 38% of British 15-year-olds in 2003 had tried cannabis - compared with 7% in Sweden and 27% in Germany.
Another said that in 2003 British 15-year-olds were the third worst binge-drinkers in Europe - only Denmark and Ireland were worse.
Britons are also more immersed in consumerism than American youngsters, the research claimed.
This was indicated by their brand awareness and the amount of importance they attached to consumer goods and possessions.
The IPPR's report is due to be published next week.