Academics asked 800 14- to 16-year-olds in 1985 and 2005 to report on their levels of theft, vandalism, truancy and drug use. Scores for many of these were lower in the second study.
Only 19 per cent of boys admitted to fighting in 2005, compared with more than 40 per cent in the previous study; 26 per cent were self-confessed truants, compared with more than 50 per cent 20 years ago; only 10 per cent admitted to stealing, compared with 23 per cent previously; and vandalism had dropped 10 percentage points.
"It shows that teenagers are not all out of control," said Colin Pritchard, of Bournemouth University's institute of health and community studies.
While the findings undermine myths of an Asbo generation addicted to wayward behaviour, scores for drinking had increased since 1985, from 52 to 68 per cent for boys, with a more marked increase for girls, and there was a marginal rise in drug use.
Girls' behaviour had also worsened in other ways, with the percentage who were stealing and truanting outstripping boys. "More girls are exhibiting the bad aspects of male behaviour, which is saddening," Professor Pritchard said.
Commentators believed diminishing behaviour problems could be explained by rising affluence. In the 1980s the UK suffered high unemployment and strikes.
"Criminologists will tell you that one of the strongest predictors of crime rates is the state of the economy," said Kathy Evans, policy director at the Children's Society. "Improved pastoral care in schools and changes in criminal justice policy could also be a factor.
"More importantly, this evidence contradicts demonising stories that suggest young people are getting worse."