Friday, November 6, 1998 Published at 10:29 GMT
The importance of not being earnest
Lack of playtime could be a factor in the rise of ADHD
Hyperactive children could be suffering from the modern world's restrictions on play.
In the US, one in 18 school children suffers from ADHD and half are being treated with the psycho-stimulant drug Ritalin.
The number of children with the disorder has risen by a huge 600% since 1990 and the US has five times more cases than the rest of the world put together.
But the problem is growing in the UK as well. There were 2,000 prescriptions for Ritalin six years ago. There are now more than 90,000.
Children with the disorder are extremely hyperactive and find it difficult to concentrate for even short periods.
They act on impulse and often appear to have no sense of danger.
Professor Alan Fridlund, an American behavioural psychologist, says he believes part of the reason for the steep increase is restrictions on play.
"There is increasing emphasis on children being able to sit still for a long time. Play suffers as a result," he said.
"There is a danger in pathologising and medicating ADHD."
He said this could lead to children being "doubly victimised" by being denied playtime and being treated for the resulting problems.
Boys were more likely than girls to have problems paying attention in class.
Professor Tony Pelligrini, one of the team members, said: "There is a danger in minimising the importance of play," he said.
Some US schools have replaced playtime with more academic classes, which researchers say may influence ADHD.
They say fears about traffic and crime are also inhibiting children's ability to play.
She is worried that parents and doctors may be becoming too reliant on drugs such as Ritalin.
She says it is good at improving attention in class and ability to do subjects like mathematics, but has bad effects on creativity and problem-solving.
There are also concerns about its long-term effects.
The causes of AHDH are not clear. It is thought that it may be an inherited condition.
Scientists have found that the frontal lobes of the brains of children with ADHD are around 5% smaller than average.
Neuroscientist professor Jaak Panksepp, who is based in Ohio and has been researching animal emotions for many years, says rats who have had the front part of their brain shrunk are more playful as a result.
He says this is because reducing the part of the brain which controls conscious thought makes rats less able to regulate their primary impulses.
They say it is related to laughter which is one of the first reciprocal interactions between mother and baby.
Professor Robert Provine, a US neuroscientist, has researched the sounds of laughter and says they are "equivalent to an animal call or a bird song".
He found that laughter was often automatic and spontaneous and could often not be provoked in laboratory conditions through watching comedy videos.
He says laughter is about social relationships rather than humour.
Professor Panksepp's study of animals found that rats also "laughed" and enjoyed play.
He deduced that laughter and play was an ancient response and part of the evolution of mammals.
His research was backed by a chance finding by a neurosurgeon in Los Angeles.
Professor Itzak Fried discovered, when he tried to locate the area of the brain which controlled an epileptic patient's seizures, that she would laugh when one part of her brain was stimulated.
Ancient and modern
Professor Provine believes that laughter is both an ancient and modern response.
He thinks the fact that humans laugh spontaneously and also laugh at jokes shows that they have taken an ancient response and developed in a more advanced part of their brain.
British research also shows how the brain suppresses pleasurable sensations which have no social purpose.
Sarah-Jayne Blakemore at the Institute of Neurology found that patients were more likely to laugh if tickled by a robot than if they tickled themselves.
"It may be that there is no point laughing to your own tickle because it is not biologically important," she said.
Children with ADHD have problems with social relationships.
They are likely to have poor self esteem and feel rejected by their peers.
Teachers and professionals often do not understand them and they feel blamed and their parents are under great strain.
Jacky Coole's son Louis has AHDH. She said he only slept for two hours a night as a baby and by the time he was seven the family were at their wit's end.
He was put on Ritalin.
"No mother or parent wants their child on any form of drugs," she said. "But Louis cannot manage socially without medication."
In the USA, however, the University of Los Angeles' Child Development Center is trying to develop alternatives.
It teaches children with ADHD how to learn through play by keeping their minds' constantly stimulated and building their self esteem.
But even so, some of the children still need drugs and the work is expensive.
Scientists are still looking for alternative ways to deal with ADHD as the numbers of children affected continues to rise.
Horizon's Beyond a Joke is on BBC2 at 9.25pm GMT on 5 November 1998.