THE DEMISE of the traditional family structure in Britain is not to blame for an increase inemotionaldistressand behaviour problems among teenagers, a controversial new study claims.

The study has examined the connection between the changing nature of familiesandariseindisobedience, stealing,lyingandfightingamong adolescents.

Despite the growth of single-parent households frequently being cited as a contributoryfactorinsocialbreakdown, researchers found that conduct problems have increased at a similar rate among all types of families over the past three decades. And they have warned that there appears to be no simple connection between changes in family structure and an increase in antisocial conduct among youths.

Lastweekareportpublishedby the Office of National Statistics predictedthat,by2014,married couples could account for less than half of British families.

Tory leader David Cameron is among those who have voiced fears over the decline of the traditional family unit, stating earlier this year: "We have the highest rateoffamilybreakdownin Europe and we have the worst social problems in Europe. Don't tellmethesethingsaren't connected."

The new research, which is duetobepublishedinthe journalSocialScienceand Medicinelaterthisyear, compared parents' ratings of conduct problems among 15 and16-year-olds,aswellas familyincomeandsize,in 1974, 1986 and 1999.

StudyleaderDrStephan Collishaw,oftheInstituteof Psychiatry at King's College, London,saiditrevealedthat behaviourproblemshadincreasedata similar rate in both traditional "intact" families and single-parent families, as well as in low-income and well-off families.

In addition, it found that while livinginastep-familyhas becomemorecommon,this became less strongly associated with behavioural difficulties.

"Although most young people are well-adjusted, happy and successful, evidence also shows an increase in young people's emotional distress and rates of conduct problems," Collishaw said.

"The findings of our study demonstratethereisnotastraightforward connection between changes in family type and income and an increase in youth antisocial behaviour.

"We still don't have a complete explanationofwhywehavechangesin adolescent mental health, but we are hopingthesefindingsstoppeople making simplistic assumptions about what the causes might be, particularly in relation to factors like family type."

The new study is part of a series of projects examining adolescent mental healthwhichhasbeenfundedby charitable trust, the Nuffield Foundation. This was triggered by previous research by Collishaw and his team, who found a "substantial" increase in adolescent behaviour problems over a 25-year period affecting males and females of all social classes.

Other recent reports have also raised major concerns about the wellbeing of teenagers in the UK, including a study published earlier this year by Unicef, which revealed that Britain's children are the unhappiest in the West.

Dr Ann Hagell, director of the adolescent mental health programme at the Nuffield Foundation, said there were many factors which could be having animpact,includingparenting methods, use of drugs, and issues in education, such as an increase in examinations and tests.

"The most interesting questionsreallyrelatetothe international comparisons - whythesethingslookabit different for the adolescent group in the UK than theydoinsouthern Europe or even in the US?" she added.

"There are quite a lot of policy questions in there, such as questions about the age at which people are allowed to drink, whether theyareliving withtheirfamilies or whether the majority of the populationgothrough college."

Chris Pond, the chief executive of the charity One ParentFamilies/Gingerbread,saidthenewstudy emphasised the need to focus on supportingchildreninalltypesof families, rather than on "outdated myths" about lone parents.

"We've heard lots in recent weeks about lone parents' supposed responsibility for social problems," he said, "but this research shows once again that there is no simple link between lone parenthood and poor outcomes for children."

Michael Scanlan, a spokesman for theFamilyandParentingInstitute, added:"Whatreallymattersisthe environment in which children grow up in - if it is loving, healthy and caring, then no matter whether it is a one or two-parent family, children are going to thrive."