One in 20 children may suffer from a syndrome which psychiatrists have labelled DAMP, a cocktail of hyperactivity, a lack of attention and clumsiness.

A child with DAMP has a combination of attention deficit hyperactivity disorder (ADHD) and developmental coordination disorder (DCD) and was once dismissed as clumsy, disruptive and out of control.

But recent studies in Sweden have shown that far from being 'naughty' such children suffer from a specific syndrome that once properly diagnosed can be managed, the annual meeting Royal College of Psychiatrists was told this week.

Dr Christopher Gillberg, professor of child and adolescent psychiatry at the University of Gothenburg, Sweden and the University of St George's Hospital Medical School, London, said that 1-2 per cent of children had severe symptoms of DAMP, while a further 3-6 per cent had moderate symptoms.

Prof Gillberg found that half of all children who had been diagnosed with ADHD also had DCD - and vice versa - and therefore had DAMP which stands for Deficits in Attention Motor control and Perception.

In one study of about 3,500 children born in Gothenburg in 1971, 61 were found to have DAMP. They were screened throughout their childhood and were found to have high rates of learning and behavioural problems. The vast majority were academic failures and had more accidents than their peers.

Symptoms often could be noticed when the child was under two and increased with age. Prof Gillberg found that at the ages of seven, 13 and 16, more than 60 per cent had a plethora of behavioural and psychiatric disorders, as well as reading, writing and learning difficulties.

Girls with the conditions often failed to be diagnosed, as they tended to be less aggressive.

Very often these children also had symptoms of autism, tics and marked learning problems, including dyslexia. They often had slightly lower IQ than the general population and sometimes had problems hearing if there was the slightest background noise.

As well as being poor readers, they were clumsy and had difficulty knowing their physical boundaries and where their hands or fingers ended.

"They are a bit like the London Symphony Orchestra, but without a conductor," said Prof Gillberg.

DAMP can run in families with at least half of the children with the condition having a mother, father or first relative with the condition. Often parents of DAMP children smoked or abused alcohol.

Despite the prevalence of DAMP, Prof Gillberg ruled out screening all children foer the syndrome but did suggest that children suspected of having ADHD be also be screened for DCD and therefore DAMP.

DAMP can be addressed successfully with stimulant medication, teaching in small groups and a change in attitude, particularly among teachers.

The Gothenbuirg study found that 58 per cent of the children not treated with stimulants had, at the age of 22, severe personality disorders and had committed a severe criminal offence and were abusing drugs or alcohol.

"I was shocked by the findings," said Prof Gillberg. "We are now doing a new follow up study and the status of these children at 30 is just terrible.

"They are so much worse off in terms of education and employment than the general population. Only one in the one group of 61 we saw had been to university.

"The majority of kids do dreadfully in the classroom. They can't listen, they can't sit still and they can't pay attention, unless they sit right at the front under the teacher's nose.

"The only thing that helps is to learn in a small classroom. Those in classes with few than eight pupils did the best. We must learn that all these children and adults are individuals and changes in attitude are more important than treatment."