ASD is a neurodevelopmental disorder which is part of an umbrella group of conditions known as Pervasive Developmental Disorders.
ASD can cause a wide range of symptoms, which are grouped into three categories, sometimes referred to as the 'Triad of Impairment':
There is currently no cure for ASD. However, a wide range of treatments, including specialist education and behavioural programmes, can help improve symptoms. Read more about treating ASD.
The conditions are more common in boys than girls. Boys are three to four times more likely to develop an ASD than girls.
The term "spectrum" is used because the symptoms of autism spectrum disorder (ASD) can vary from person to person and range from mild to severe.
It is also common for children with ASD to have symptoms or aspects of other conditions such as:
There are three main types of ASD:
Children with autism usually have significant problems with language, social interaction and behaviour. Many children with autism also have learning difficulties and below-average intelligence.
Children with Asperger Syndrome have milder symptoms that affect social interaction and behaviour. Their language development is usually not affected. However, they often have problems in certain areas of language, such as understanding humour, sarcasm or figures of speech ("It's raining cats and dogs", or "Pull your socks up!" for example).
Children with Asperger Syndrome usually have intelligence within the normal range. Some children have particular skills in areas that require logic, memory and creativity, such as maths, computer science and music.
PDD-NOS is diagnosed in children who share some, but not all, of the traits of Autism or Asperger Syndrome.
Most children with PDD-NOS have milder symptoms than children with Autism, but they do not share the language skills and normal range of intelligence associated with Asperger syndrome.
Autism can normally be diagnosed in children at around the age of two. However, it can be difficult to diagnose as the symptoms will often only become more noticeable as they get older.
See your GP if you notice any of the symptoms of ASD or if you’re concerned about your child’s development. You can discuss your concerns together in depth before deciding whether your child should be referred for a specialist assessment. Read more about diagnosing autism.
If your child is diagnosed with ASD, there will be many things to consider as a parent, including coping with daily life at home and choosing the right school. Read a parent's guide to autism for more information about coping with your child’s diagnosis.
Some people with ASD grow up without ever being diagnosed, sometimes through choice. However, getting a diagnosis of autism spectrum disorder (ASD) as an adult can often help people with ASD and their families understand the condition and work out what kind of support they need.
A range of autism-specific services is available to help adults with ASD find advice and support, get involved in leisure activities and find somewhere they are comfortable living.
Some adults with ASD may also have difficulty finding a job because of the social demands and changes in routine that working involves. However, they can get support to help them find a job that matches their abilities and skills.
Read more about living with autism spectrum disorder (ASD) as an adult.
The number of diagnosed cases of ASD has increased over the past 20 years, but this does not necessarily mean that the condition is becoming more widespread.
Some experts argue that the rise in diagnosed cases may be due to health professionals getting better at diagnosing cases correctly. In the past, many children with an ASD may have been incorrectly labelled as "slow", "difficult" or "painfully shy", and not given the treatment they needed.
Some campaigners believe that the rise in cases is due to the MMR (mumps, measles and rubella) vaccine.
The MMR vaccine has been investigated extensively in a number of major studies around the world, involving millions of children. Researchers have found no evidence of a link between MMR and ASD.
In 2009, one of the country's leading ASD charities, the National Autistic Society, released a statement supporting the claim that there is no link between MMR and ASD.
In the US, a compound containing mercury called Thiomersal, which is used as a preservative in some vaccines, has also been claimed to cause ASD.
Thiomersal has been extensively studied and no evidence of a link to ASD has been found. Furthermore, Thiomersal was removed from vaccines in the US after 1999, yet the rates of ASD have continued to rise.
Children with moderate symptoms who have average or above-average intelligence often grow up to be independent adults with jobs, long-term relationships and have children of their own.
Children with more severe symptoms who have below-average intelligence are likely to find it difficult to live independently as adults and may need additional care and assistance. However, there is no reason why they cannot enjoy a good quality of life.