Smoking linked to ADHD kids

WOMEN who smoke while pregnant have been given another reason to quit, after a study found it might cause their child to become unruly and badly behaved.

A link was also discovered to attention deficit hyperactivity disorder (ADHD).

Antisocial behaviour includes activities such as destroying belongings, bullying, stealing, telling lies and disobedience.

The links were measured with a questionnaire that provided scores based on the level at which such behaviour was experienced.

Previous studies have shown a more general association between smoking when pregnant and a child's bad behaviour, but it was not known whether the bad behaviour was caused by ADHD.

The new study makes it clear smoking while pregnant can directly lead to antisocial behaviour, regardless of whether the child has ADHD.

Simon Chapman, professor of public health at the University of Sydney, said the finding published in the British Journal of Psychiatry "potentially affects quite a lot of people" given the high rates of smoking.

Professor Chapman is editor of a journal called Tobacco Control, but said he was unaware of much previous work in the area and the latest study results appeared to be both reliable and significant. "This is just another black mark against smoking," he said.

The new study of 723 identical and 1173 non-identical pairs of British twins found antisocial behaviour was linked to maternal smoking in its own right.

Because only identical twins share the same genes, comparing sets of identical and non-identical pairs can separate influences on health that are genetic or environmental.

The research, which covered a population of twins born between 1980 and 1991 in Manchester, showed smoking while pregnant accounted for 3 per cent of the pattern of variation in antisocial behaviour. It also accounted for 2 per cent of the variance in ADHD.

The data suggested smoking had a distinct influence on each condition.

Additional reporting: PA