Autism comes by degrees. People with the milder form, Asperger’s syndrome, display communication difficulties and “obsessional” interests. In severe cases, however, it can be as if your child is locked in a glass bubble, staring vacantly past you as you desperately try to make eye-contact.

The thought of never being able to fully communicate with your child, or to know what is going on inside his or her mind, can be heartbreaking. And this is not helped by the fact that autism is still the focus of many wild claims and misconceptions. However, with a recent report stating that autism costs the UK economy £28 billion a year, a better public understanding of this condition is desperately needed.

Fortunately, in my 26 years of working with people with autism and their families, and now as director of the Autism Research Centre at Cambridge University, I have seen vast improvements in the understanding of autism by the medical, psychological and educational professions, and among the public. I have also seen the growth of educational and clinical provision, and specialist techniques improve, so now we have the capability to provide excellent support for people with autism and their families. Here are the latest scientific theories on what causes autism, beneficial interventions and some commonly held myths.

WHAT ARE THE CAUSES?

According to a study in The Lancet last year, an estimated 1 per cent of the population lie somewhere on the autistic spectrum. This figure represents an increase over earlier ones but this rise is likely to be due to better diagnosis and awareness of the condition. Autism spectrum conditions result from alterations in brain development, affecting how an individual perceives, learns and communicates. The two main subgroups are autism and Asperger’s syndrome (see box).

Using the latest brain scanning methods such as fMRI (functional magnetic resonance imaging), studies from labs in Cambridge and London, and confirmed in labs around the world, have revealed that certain brain areas are underactive in people with autism. The amygdala (sometimes thought of as the emotion centre) and the medial prefrontal cortex (involved in social behaviour) are underactive in people with autism spectrum conditions when they are trying to decode another person’s facial expression.

Studies from San Diego suggest that the autistic brain is also growing too fast in early childhood, and researchers in Carnegie Mellon University have found that different regions of the brain are not connected in the usual way. New work from Cambridge suggests that elevated testosterone levels in the foetus, in the second trimester of pregnancy, is associated with a greater number of autistic traits. This finding may help to explain why many more boys than girls develop an autism spectrum condition. In New York, researchers are experimenting with boosting levels of a different hormone, oxytocin. This is sometimes called the “love hormone”, as levels increase in intimate relationships. Elevated levels of the hormone are associated with being more trusting and better able to read emotional expressions. It may be relevant that women produce twice as much oxytocin as men.

Autism and Asperger’s syndrome run in families. If there is one child who has a diagnosis on the autistic spectrum, the likelihood of another child also having a diagnosis is about 5-10 per cent, which is higher than the general population rate. Molecular genetic studies are focused on identifying the key genes that might play a role in increasing the risk of a diagnosis. Studies of twins have established that it is not 100 per cent genetic, since even among identical twins, when one has autism, the likelihood of both twins having autism is only about 60 per cent. This means there must also be an environmental component, but what it is remains unknown.

WHAT HELPS?

People with autism or Asperger’s syndrome need family and individual support, delivered by social services, special education, sheltered employment and sheltered living (where necessary). Schools such as TreeHouse in North London are excellent examples of what can be provided: small class sizes, at times even one-to-one teacher-child ratios, where teaching is aimed at building simple skills and rewarding the child for every small step they make. Specialist teachers shape such skills into more complex ones, giving the child the experience of success and thus self-confidence. Such schools have to be highly organised because such children have problems in coping with unexpected change.

Recent work has shown that tailor-made children’s animation may benefit children with autism. Among the more unusual nominations at this year’s Bafta Children’s Awards was The Transporters, a children’s animation DVD, with tram, train, tractor and cable car characters, in which human faces have been grafted on to the vehicles. It was created with government funding to help children with autism improve their emotion recognition. The idea behind it was that the child with autism is drawn to watch the predictable, mechanical movement of the vehicles. Putting faces on to vehicles means that the child is exposed to human faces showing emotions. This year the Government gave 40,000 free copies of the DVD (see www.transporters.tv ) to families with a child on the autistic spectrum under the age of 8. This animation builds on other specialist educational software (for parents and teachers to use), such as Mind Reading, a DVD that shows actors expressing every human emotion in the face and the voice, to teach people with autism the skill of emotion recognition (www.jkp.com/mindreading ).

The message is that a diagnosis of autism does not mean there is no hope for learning and development. Parents, therapists and teachers wanting to know which methods to try should visit a wonderful new website (www.researchautism.net ) that provides impartial summaries of the evidence for or against a different method.

MYTHS ABOUT AUTISM

The MMR vaccination causes autism

There is no strong evidence for this claim. In Japan, for example, although the rates of autism were rising (as they have been worldwide), they continued to rise even after the withdrawal of the MMR public health programme.

Autism is caused by poor parenting

This idea has been disproved. Autism is found in families where other children have been raised successfully, and the fact that autism involves atypical neurological development from the earliest stage shows that it is not a reaction to parental behaviour.

For more information, The National Autistic Society, www.nas.org ; the Autism Research Centre at Cambridge University, www.autismresearchcentre.com . Professor Baron-Cohen is the author of Autism: The Facts (OUP, £15)

What’s the difference between autism and Asperger’s syndrome?

Differences in IQ

In autism the person may have additional learning difficulties (below average IQ), while in Asperger’s the person has average or above average IQ.

Language development

In autism there is language delay (a child not using words by the age of 2) whereas in Asperger’s syndrome a child’s speech develops normally.

Social difficulties

Autism is easier to recognise than Asperger’s: the child with autism may be so avoidant of others that it is plain to see his or her social difficulties. A child with Asperger’s, in contrast, has more subtle social difficulties. He or she may question people intrusively; or talk about their favourite topic (for instance, the names of all lizards in Africa) long after their listener has lost interest in the conversation.

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