The development of a separate youth culture could be responsible for the rapid post-war rise in anti-social behaviour, according to a new study.
Professor Sir Michael Rutter, head of the Department of Child and Adolescent Psychiatry at the London Institute of Psychiatry, said the development of psychosocial disorders had occurred at a time of economic boom and could not be attributed to worsening living conditions.
"Young people have become a separate class," he said. "They have their own culture, their own dress and music and have less contact with other age groups."
The report suggests that marking adolescents off as a separate group runs the risk of reducing the influence of adults on their behaviour and increase the power of the peer group.
However, Sir Michael warned against seeking a single solution to a problem that had occurred across the industrialised world. "It would seem that something as striking as this ought to have a simple explanation and it's very frustrating that that's not what comes out of the study," he said.
Written by Sir Michael and David Smith, Professor of Criminology at the University of Edinburgh, the study examined suicides, drug and alcohol use, anorexia nervosa and bulimia and crime among 12 to 26-year-olds. It found:
tSubstantial increases in disorders in nearly all countries during the past 50 years.
tThe rise was sudden. There were no similar increases earlier in the century despite urbanisation and unemployment.
tAs psychosocial disorders were increasing, physical health was improving.
tSuicide rates showed the highest increase among young males, with rates up to three times that of females.
tSteadily rising levels of drug dependency.
tAll the major psychosocial disorders studied began or peaked during teenage years. Criminal behaviour was most common among 17-year-olds.
Several tentative causes are put forward including family break-ups, longer adolescence, a more consumerist society and greater individualism.
Mr Smith said there was a paradox that the rise social disorders had occurred during the "golden era" of economic expansion. Although unemployment and poverty were useful in explaining individual behaviour, they provided no guide to the causes over time. Crime had risen in most societies, although Japan - which had experienced the most dramatic growth rates between 1950 and 1973 - experienced a fall in reported crime over a 40-year period to 1990.
Unemployment statistics over time did not correlate with disorder and a general increase in unemployment in the 1970s and 1980s had not been associated with a similar rise in the rate of increase of disorder.
Family discord and divorce were said to have been influential but it appeared the main risk was from parental confrontation, rather than the act of divorce.
The changing nature of adolescence was highlighted as one of the most important factors as children enter puberty earlier but are not accepted as adults until much later. "Lengthened adolescence might mean the prolongation of an insecure status, and of an uncertain personal identity. It might lead to internal conflicts and to clashes with paternal or other authority," the study says.
Sir Michael said the research presented an exciting challenge. "If there has been such a marked rise over time, then it ought be possible to provide an equally dramatic fall if we understood the processes that underlined the rise."
tPsychosocial Disorders in Young People; Sir Michael Rutter and David Smith; published by John Wiley & Sons on behalf of Academia Europaea; pounds 49.95.