Autism and Asperger syndrome Dr Trisha Macnair Autism and Asperger syndrome are part of a range of disorders that cause communication and emotional problems. To people with these disorders the world can appear chaotic with no clear boundaries, order or meaning.

In this article

What causes it? What are the symptoms?

Who's affected? How's it diagnosed?

What's the treatment?

Autism and Asperger syndrome belong to a group of conditions that can vary from very mild, where the person can function as well as anyone else around them, to so severe that they are completely unable to take part in normal society.

People with autism are usually more severely disabled, while those with Asperger syndrome tend to be more able, although this isn’t always so. Because of the range of severity and symptoms, the conditions are collectively known as autistic spectrum disorders.

The cause of autistic spectrum disorders is not yet clear. Genetics play an important role, and researchers are examining a number of chromosome sites that could be implicated. It's likely autism occurs when a small number of genes interact in a specific way, possibly linked to some external event or factor.

Brothers or sisters of a child with the condition are 75 times more likely to develop it

This genetic link means there may be an inherited tendency, so autism and Asperger syndrome may run in families. Brothers or sisters of a child with the condition are 75 times more likely to develop it.

Doctors' ability to diagnose these disorders has improved in recent years, but older people, particularly with milder problems, may never have been diagnosed. When a child is diagnosed, parents often realise they've had the same problems themselves.

A variety of other environmental factors that affect brain development before, during or soon after birth, also play a part (possibly acting as a trigger). However, despite reports suggesting a possible link between MMR vaccination and autistic spectrum disorders, scientific evidence has confirmed the vaccination does not increase the risk.

The main three symptoms are:

• Difficulties with social interaction - being unaware of what's socially appropriate, finding chatting or small talk difficult and not socialising much (people with autism find it very difficult to develop friendships and relate to others)
• Problems with verbal and non-verbal communication - understanding gestures, body language, facial expressions and tone of voice, making it difficult to empathise with people's feelings
• Imagination impairments - such as not enjoying or taking part in role-play games

These behavioural difficulties can cause a great deal of stress for members of the family.

Babies who develop autism later may appear normal at first and reach the usual developmental milestones, including early speech. But as they grow into toddlers, they may fail to develop normal social behaviour and speech may be lost.

As a child grows, the typical difficulties of autistic spectrum disorders are:

• Repetitive behaviour and resistance to changes in routine
• Obsessions with particular objects or routines
• Poor coordination
• Difficulties with fine movement control (especially in Asperger syndrome)
• Absence of normal facial expression and body language
• Lack of eye contact
• Tendency to spend time alone, with very few friends
• Lack of imaginative play

Autism tends to produce more severe symptoms. For example, a child with autism may fail to develop normal speech (the development of spoken language is usually normal in Asperger syndrome) and as many as 75 per cent of people with autism have accompanying learning disabilities.

Seizures are also a common problem, affecting between 15 and 30 per cent of those with autism.

Conversely, autistic children are sometimes found to have an exceptional skill, such as an aptitude for drawing, mathematics, or playing a musical instrument.

It's estimated that more than 580,000 people in the UK have autistic spectrum disorders.

Boys are more likely to be affected than girls, though research suggests that when girls have the condition they may be more severely affected.

There's no specific test for autistic spectrum disorders. Diagnosis is based on a consideration of symptoms, and milder cases may be missed.

Appropriate specialist education, speech, language and behavioural therapy are all important

There is no specific cure or particular medical treatment for autism, but much can be done to maximise a child’s potential and this is key to managing the condition. Appropriate specialist education, speech, language and behavioural therapy are all important. There are many different approaches, some of which are based around theories about possible causes of autistic spectrum disorders (for example, the Son-Rise programme).

While many people feel they've achieved good results with some of these interventions, none of them is a cure-all, and many lack scientific evidence to demonstrate their benefits.

Others claim dietary changes or alternative remedies have helped, but these, too, are mostly unproven.

Medication is sometimes recommended when it's felt to be of benefit to the child, for example to control seizures, depression or other symptoms.

As the precise events that lead to autistic spectrum disorders aren't yet known, it isn't possible to prevent them. Neither is there yet a simple screening test to identify people carrying genes that might increase susceptibility to autism.

This article was last medically reviewed by Dr Rob Hicks in November 2007