thousands of disturbed children are being unnecessarily prescribed drugs to calm them, an expert claimed last night.

Youngsters suffering from attention deficient and hyperactivity disorder (ADHD) are being given the Class A amphetamine Ritalin and anti-depressants such as Prozac.

Around 10,000 children in the UK are prescribed such medication for psychological problems and behavioural disorders.

But Ms Janice Hill, founder of Edinburgh-based mental health support group Overload, speaking on the eve of a conference on the situation in Edinburgh, said: ''It's sinister and we would urge the conference to try to tackle these issues instead of thinking Ritalin was a straightforward solution.''

She added: ''Children could have learning difficulties, they could be deficient in vitamins, intolerant to certain foods, have thyroid problems, chemical imbalances, or a host of conditions.

''We really need to know more. Dishing out the dope is not the best way to help disturbed youngsters.''

Ms Hill, who has 20 years of experience in the field, has children referred to her for help by education authorities and worried parents.

''These children are pawns in the power games of multi-national drug companies.

''They are being used as guinea pigs,'' she said.

''I've had hundreds of children from schools across Edinburgh and Lothian referred to me by education authorities and worried parents.

''It is a diabolical situation because drugs like Ritalin are in effect, speed, and it has the opposite effect on children as it does on healthy adults.

''In adults it speeds you up. But in children it is supposed to have a calming effect.

''But I've seen children so messed up with these drugs that they don't know where they are or what is going on.''

The claims were made as the UK's leading psychiatrists and doctors gathered in Edinburgh to discuss behavioural problems in children and young people.

ADHD arises because of a deficiency of the brain chemical dopamine, which controls emotions, concentration, and motivation.

Sufferers fidget, are easily distracted and often interrupt other children.

Acute cases dealt with by Ms Hill's group include violent children who dig up dead animals, feed bleach to pets, and put goldfish in boiling water.

Once ADHD is identified, many doctors believe the condition can be controlled with Ritalin, which is prescribed to 100,000 people, including 10,000 children, in Britain.

Ms Hill said: ''Doctors and psychiatrists dispense Ritalin as if it is a cure-all drug.

''In America the situation is so bad that millions of children are on Ritalin.''

Prescription of Ritalin has gone up from 2000 in 1991 to nearly 100,000 in 1999. The side effects include increased agitation, nervousness, loss of appetite, weight loss, and vomiting.

In more extreme cases, Ritalin can cause chest paints, fast or irregular hearbeats, and uncontrollable body movements.

Doctors and psychiatrists will meet at the Royal College of Physicians of Edinburgh today to discuss the problem.

They are expected to lay down guidelines for the best way to treat children with ADHD.

Speakers include Dr Chris Keinar, a senior lecturer in child health at Edinburgh University, and Professor Peter Hill, professor of child psychiatry at the Royal Hospital for Sick Children in London.

Dr Joanne Barton, chairwoman of the working group on ADHD, said: ''There are some people who think Ritalin is under-prescribed in the UK compared to countries like America and Australia.

''The purpose of the programme is to discuss the findings of the last 12 months from all sides of the debate.''