Behaviour link to lifelong health
Psychologists doubt the results would apply to badly behaved children today
People who behaved badly at school are more likely to suffer mental health and social difficulties as adults, a 40-year-study of Britons suggests.
Canadian researchers writing in the British Medical Journal examined data from 3,500 people from the age of 13 until they reached their 40s or 50s.
Those who had school behaviour problems were more likely to be depressed, divorced or have financial problems.
ut a psychologist questioned whether the same would apply in other eras.
I'd like to think that things are much different today, and that today's children would not have these problems later in life
In the late 1950s and the start of the 1960s, teachers across Britain were asked to rate the behaviour of a nationally representative sample of children, all of them born in 1946, as they entered their early teenage years.
A quarter of the children were described by the teachers as having some sort of mild or more severe behavioural problem.
The participants were then reinterviewed between the ages of 36 and 53, asked about their mental health, and social and economic status.
Those who had been described as having behavioural problems by their teachers decades earlier were more likely to have left school with no qualifications, and to suffer a number of problems in adulthood.
These included depression and anxiety, failed relationships, teenage pregnancy, and financial difficulties.
Even when the results were adjusted to take account of other factors, such as sex, the social class of parents, depression in adolescence and IQ, the link to behaviour held true.
The researchers, from the University of Alberta, wrote: "Given the long-term costs to society, and the distressing impact on the adolescents themselves, our results might have considerable implications for public health policy."
However, Linda Blair, a clinical psychologist who works with families, said that she believed that in general the children born in the 1940s faced a completely different school and home environment to those born today.
Harsh criticisms and discipline for bad behaviour would have contributed to a "vicious cycle" of low self-confidence and poor achievement, she said.
She said: "You can't imagine anyone back then asking a child how they felt about something.
"I'd like to think that things are much different today, and that today's children would not have these problems later in life.
"The key thing is how you respond to behavioural problems in schools - hopefully we now handle them in a way that will increase self-esteem, not reduce it."