Autism spectrum disorder

22 min read

What is autistic spectrum disorder?

Autism spectrum disorder (ASD) is the name for a range of similar conditions, including Asperger syndrome, that affect a person's social interaction, communication, interests and behaviour.

In children with ASD, the symptoms are present before three years of age, although a diagnosis can sometimes be made after the age of three.

It's estimated that about 1 in every 100 people has ASD. More boys are diagnosed with the condition than girls.

There's no "cure" for ASD, but speech and language therapy, occupational therapy, educational support, plus a number of other interventions are available to help children and parents.

Read about

help and support available for people with ASD

Signs and symptoms

People with ASD tend to have problems with social interaction and communication.

In early infancy, some children with ASD don’t babble or use other vocal sounds. Older children have problems using non-verbal behaviours to interact with others – for example, they have difficulty with eye contact, facial expressions, body language and gestures. They may give no or brief eye contact and ignore familiar or unfamiliar people.

Children with ASD may also lack awareness of and interest in other children. They’ll often either gravitate to older or younger children, rather than interacting with children of the same age. They tend to play alone.

They can find it hard to understand other people's emotions and feelings, and have difficulty starting conversations or taking part in them properly. Language development may be delayed, and a child with ASD won’t compensate their lack of language or delayed language skills by using gestures (body language) or facial expressions.

Children with ASD will tend to repeat words or phrases spoken by others (either immediately or later) without formulating their own language, or in parallel to developing their language skills. Some children don’t demonstrate imaginative or pretend play, while others will continually repeat the same pretend play.

Some children with ASD like to stick to the same routine and little changes may trigger tantrums. Some children may flap their hand or twist or flick their fingers when they’re excited or upset. Others may engage in repetitive activity, such as turning light switches on and off, opening and closing doors, or lining things up.

Children and young people with ASD frequently experience a range of cognitive (thinking), learning, emotional and behavioural problems. For example, they may also have

attention deficit hyperactivity disorder (ADHD)
, or

About 70% of children with ASD have a non-verbal IQ below 70. Of these, 50% have a non-verbal IQ below 50. Overall, up to 50% of people with "severe learning difficulties" have an ASD.

Read more about the

symptoms of ASD

Getting a diagnosis

The main features of ASD – problems with social communication and interaction – can often be recognised during early childhood.

Some features of ASD may not become noticeable until a change of situation, such as when the child starts nursery or school.

See your doctor or health visitor if you notice any of the signs and symptoms of ASD in your child, or if you're concerned about your child's development. It can also be helpful to discuss your concerns with your child's nursery or school.

Read more about

diagnosing ASD

Caring for someone with ASD

Being a carer isn't an easy role. When you're busy responding to the needs of others, it can affect your emotional and physical energy, and make it easy to forget your own health and mental wellbeing.

If you're caring for someone else, it's important to look after yourself and get as much help as possible. It's in your best interests and those of the person you care for.

What causes ASD?

The exact cause of ASD is unknown, but it's thought that several complex genetic and environmental factors are involved.

In the past, some people believed the MMR vaccine caused ASD, but this has been investigated extensively in a number of major studies around the world, involving millions of children, and researchers have found no evidence of a link between MMR and ASD.

Read more about the

causes of ASD

Autism in adults

Some people with ASD had features of the condition as a child, but enter adulthood without ever being diagnosed.

However, getting a diagnosis as an adult can often help a person with ASD and their families understand the condition, and work out what type of advice and support they need.

For example, a number of autism-specific services are available that provide adults with ASD with the help and support they need to live independently and find a job that matches their skills and abilities.

Read more about

adults with ASD

Symptoms of autism spectrum disorder

The main features of autism spectrum disorder (ASD) are problems with social communication and interaction .

See your doctor or health visitor if you notice any of the following signs of ASD in your child or if you’re concerned about your child’s development.

Signs of ASD in pre-school children

Spoken language

  • delayed speech development (for example, speaking less than 50 different words by the age of two), or not speaking at all
  • frequent repetition of set words and phrases
  • speech that sounds very monotonous or flat
  • preferring to communicate using single words, despite being able to speak in sentences

Responding to others

  • not responding to their name being called, despite having normal hearing
  • rejecting cuddles initiated by a parent or carer (although they may initiate cuddles themselves)
  • reacting unusually negatively when asked to do something by someone else

Interacting with others

  • not being aware of other people’s personal space, or being unusually intolerant of people entering their own personal space
  • little interest in interacting with other people, including children of a similar age
  • not enjoying situations that most children of their age like, such as birthday parties
  • preferring to play alone, rather than asking others to play with them
  • rarely using gestures or facial expressions when communicating
  • avoiding eye contact


  • having repetitive movements, such as flapping their hands, rocking back and forth, or flicking their fingers
  • playing with toys in a repetitive and unimaginative way, such as lining blocks up in order of size or colour, rather than using them to build something
  • preferring to have a familiar routine and getting very upset if there are changes to this routine
  • having a strong like or dislike of certain foods based on the texture or colour of the food as much as the taste
  • unusual sensory interests – for example, children with ASD may sniff toys, objects or people inappropriately

Signs and symptoms of ASD in school-age children

Spoken language

  • preferring to avoid using spoken language
  • speech that sounds very monotonous or flat
  • speaking in pre-learned phrases, rather than putting together individual words to form new sentences
  • seeming to talk "at" people, rather than sharing a two-way conversation

Responding to others

  • taking people’s speech literally and being unable to understand sarcasm, metaphors or figures of speech
  • reacting unusually negatively when asked to do something by someone else

Interacting with others

  • not being aware of other people’s personal space, or being unusually intolerant of people entering their own personal space
  • little interest in interacting with other people, including children of a similar age, or having few close friends, despite attempts to form friendships
  • not understanding how people normally interact socially, such as greeting people or wishing them farewell
  • being unable to adapt the tone and content of their speech to different social situations – for example, speaking very formally at a party and then speaking to total strangers in a familiar way
  • not enjoying situations and activities that most children of their age enjoy
  • rarely using gestures or facial expressions when communicating
  • avoiding eye contact


  • repetitive movements, such as flapping their hands, rocking back and forth, or flicking their fingers
  • playing in a repetitive and unimaginative way, often preferring to play with objects rather than people
  • developing a highly specific interest in a particular subject or activity
  • preferring to have a familiar routine and getting very upset if there are changes to their normal routine
  • having a strong like or dislike of certain foods based on the texture or colour of the food as much as the taste
  • unusual sensory interests – for example, children with ASD may sniff toys, objects or people inappropriately

Causes of autism spectrum disorder

The exact cause of autism spectrum disorder (ASD) is currently unknown.

It's a complex condition and may occur as a result of genetic predisposition (a natural tendency), environmental or unknown factors.


Most researchers believe that certain genes a child inherits from their parents could make them more vulnerable to developing ASD.

Cases of ASD have been known to run in families. For example, younger siblings of children with ASD can also develop the condition, and it's common for identical twins to both develop ASD.

No specific genes linked to ASD have been identified, but it may be a presenting feature of some rare genetic syndromes, including Fragile X syndrome, Williams syndrome and

Angelman syndrome

Environmental triggers

Some researchers believe that a person born with a genetic vulnerability to ASD only develops the condition if they're exposed to a specific environmental trigger.

Possible triggers include being born prematurely (before 35 weeks of pregnancy), or being exposed in the womb to alcohol or to certain medication, such as sodium valproate (sometimes used to treat epilepsy during pregnancy).

No conclusive evidence has been found linking pollution or maternal infections in pregnancy with an increased risk of ASD.

Other health conditions

Below are some other conditions known to be associated with ASD:

  • muscular dystrophy
    – a group of inherited genetic conditions that gradually cause the muscles to weaken
  • Down's syndrome
    – a genetic condition that typically causes a learning disability and a range of physical features
  • cerebral palsy
    – conditions that affect the brain and nervous system, causing problems with movement and co-ordination
  • infantile spasms – a type of
    that develops while a child is still very young (usually before they're one year old)
  • neurofibromatosis – a number of genetic conditions that cause tumours to grow along the nerves (the main types are
    neurofibromatosis type 1
    neurofibromatosis type 2
  • the rare genetic conditions fragile X syndrome,
    tuberous sclerosis
    Rett syndrome

Diagnosing autism spectrum disorder

See your GP or health visitor if your child is showing

symptoms of autism spectrum disorder (ASD)
, or you're worried about their development.

If appropriate, your doctor can refer you to a healthcare professional or team who specialise in diagnosing ASD, or someone who has access to such a team.

The specialist or specialist team will make a more in-depth assessment, which should be started within three months of the referral.

If you're referred to an individual specialist, they may be a:

  • psychologist – a healthcare professional with a psychology degree, plus further training and qualifications in psychology
  • psychiatrist – a medically qualified doctor with further training in
  • paediatrician – a doctor who specialises in treating children
  • speech and language therapist – a specialist in recognising and treating communication problems

Some local health authorities use multidisciplinary teams. These are a combination of specialists who work together to make an assessment.


A diagnosis of ASD is based on the range of features your child is showing.

For most children:

  • information will be needed from your doctor, nursery or school staff, plus speech and language and occupational therapists, about your child's development, health and behaviour
  • a speech and language therapist, and often an occupational therapist, will carry out an assessment
  • a detailed physical examination will need to be carried out to rule out possible physical causes of your child's symptoms, such as an underlying condition like
    Down's syndrome
  • the assessment will include a check for any coexisting physical health conditions and mental health problems

In addition, for some children:

  • you may be asked to attend a series of interviews so a detailed family history and the history of your child's development and behaviour can be drawn up
  • your child may be asked to attend a series of appointments so specific skills and activities can be observed and assessed

Once this process is complete, a diagnosis of ASD may be confirmed.

After diagnosis

When a child is diagnosed with ASD, many parents are keen to find out as much as they can about the condition. The National Autistic Society has an excellent range of resources and advice.

Diagnosing ASD in adults

Some people with ASD grow up without their condition being recognised, but it's never too late to get a diagnosis. Some people may be scared of being diagnosed because they feel it will "label" them, and lower other people's expectations of them.

But there are several advantages to getting a diagnosis. It helps people with the condition and their families understand ASD and decide what sort of support they need. A diagnosis may also make it easier to access autism-specific services and claim benefits.

See your doctor if you think you may have ASD and ask them to refer you to a psychiatrist or clinical psychologist. The National Autistic Society website has information about being diagnosed with ASD if you're an adult.

If you're already seeing a specialist for other reasons, you may want to ask them for a referral instead.

Read more about diagnosing ASD in adults and

advice for adults living with ASD

Treating autism spectrum disorder

There's no 'cure' for autism spectrum disorder (ASD), but there are a range of specialist interventions that aim to improve communication skills and help with educational and social development.

It can be difficult to know which intervention will work best for your child, because each person with ASD is affected differently.

Some types of intervention can involve hours of intensive work, and this isn't always possible for many families because of the practical, emotional and financial commitments necessary.

The National Autistic Society website has information about the many different strategies and approaches available for ASD.

Any intervention should focus on important aspects of your child's development. These are:

  • communication skills – such as using pictures to help communicate (as speech and language skills are usually significantly delayed)
  • social interaction skills – such as the ability to understand other people's feelings and respond to them
  • imaginative play skills – such as encouraging pretend play
  • academic skills – the "traditional" skills a child needs to progress with their education, such as reading, writing and maths


detailed assessment
, management and co-ordination of care for children and young people with ASD should involve local specialist community-based multidisciplinary teams (sometimes called "local autism teams") working together. The team may include:

  • a paediatrician
  • mental heath specialists, such as a psychologist and psychiatrist
  • a learning disability specialist
  • a speech and language therapist
  • an occupational therapist
  • education and social care services

Local autism teams should ensure that every child or young person diagnosed with ASD has a case manager or key worker to manage and co-ordinate their treatment, care and support, as well as their transition into adult care.

The Research Autism website provides details of the many different types of autism interventions, treatments and therapies.

Parent education and training

The parents of a child with ASD play a crucial role in supporting their child and improving their skills.

If your child has ASD, it's a good idea to find out as much as you can about the condition. The National Autistic Society website provides useful information and advice for parents, relatives and carers.

The Research Autism website is also a good source of information and has a section about the different issues that living with autism presents, including the impact of autism on the family.

Communication advice for parents

Communication is particularly challenging for children with ASD. Helping your child to communicate can reduce anxiety and improve behaviour.

The following tips may be useful when communicating and interacting with your child:

  • use your child's name, so they know you're addressing them
  • keep background noise to a minimum
  • keep language simple
  • speak slowly and clearly, with pauses between words
  • accompany what you say with simple gestures
  • allow extra time for your child to process what you've said

Psychosocial treatments

If your child's behaviour is causing problems, they'll be assessed for possible triggers, such as a physical health condition, mental health problem, or environmental factors.

A physical or mental cause will be addressed using medication and/or psychological treatments.


In some cases, medication may be prescribed to treat some of the symptoms or conditions associated with ASD. For example:

  • [ sleeping problems ](/health-library/conditions/insomnia) – this may be treated with a medication such as melatonin
  • depression
    – this may be treated with a type of medication known as a
    selective serotonin reuptake inhibitor (SSRI)
  • epilepsy
    – this may be treated with a type of medication called an anticonvulsant
  • attention deficit hyperactivity disorder (ADHD)
    – this may be treated with a medication such as methylphenidate
  • aggressive and challenging behaviour, such as tantrums or
    – this may be treated with a type of medication called an antipsychotic if the behaviour is severe or psychological treatments haven't helped

These medications can have significant side effects and are usually only prescribed by a doctor who specialises in the condition being treated. If medication is offered, your child will have regular check-ups to assess whether it's working.

Treatments not recommended

A number of alternative treatments have been suggested for ASD. However, these should be avoided, because there's little or no evidence that they're effective and some may even be potentially dangerous.

Treatments that aren't recommended for ASD include:

  • special diets – such as gluten-free or casein-free diets
  • neurofeedback – where brain activity is monitored (usually by placing electrodes on the head) and the person being treated can see their brain activity on a screen and is taught how to change it
  • auditory integration training – a therapy that involves listening to music that varies in tone, pitch and volume
  • chelation therapy – which uses medication or other agents to remove metal (in particular, mercury) from the body
  • hyperbaric oxygen therapy – treatment with oxygen in a pressurised chamber
  • facilitated communication – where a therapist or another person supports and guides a person's hand or arm while using a device such as a computer keyboard or mouse

Adults living with autism

Some people with autism spectrum disorder (ASD) grow up without their condition being recognised, sometimes through choice.

However, a diagnosis can make it easier to access a range of support services that may be available locally.

It's never too late to be diagnosed with ASD, although it's not always easy because some local NHS authorities don't provide NHS funding for diagnosing ASD in adults.

Read more about diagnosing ASD in adults, or see The National Autistic Society website for further information about autism diagnosis for adults.

Treatment and support

With a proper diagnosis, adults with ASD may be able to access local autism support services, if available in their area. You can search for services for adults using the Autism Services Directory.

The healthcare professionals who diagnose you with ASD should be able to provide more information and advice about the care and support services available to you.

Read about assessing your care and support needs .

Examples of programmes that may be available in your local area include:

  • social learning programmes – to help you cope in social situations
  • leisure activity programmes – these involve taking part in leisure activities, such as games, exercise, or going to the cinema or theatre with a group of people
  • skills for daily living programmes – to help you if you have problems carrying out daily activities, such as eating and washing

Adults with ASD may also benefit from some of the treatments offered to children with ASD, such as psychological therapy and medication.

Read more about the

help and support available for people with ASD


Adults with ASD can live in all types of housing. Some people may be suited to a residential care home, while others may prefer to live on their own and receive home support. Some people with ASD live completely independently.


It can be difficult for people with ASD to find a job. For example, they may find the work environment too noisy, or travelling to work may be too stressful because of the crowds. Sudden changes in routine can also be upsetting.

However, in the right job and with the right support, people with ASD have much to offer. They're often accurate, reliable, and have a good eye for detail. Being in a working environment can help the individual's personal development tremendously.

If you're having problems getting a job or staying in a job, you may be able to access a supported employment programme in your local area. These programmes can help you write your CV and job applications, and prepare you for interviews. They can also help you choose which jobs would suit you and provide training for that role.

Those providing the programme can also advise employers about any changes that need to be made to the workplace to suit people with ASD, as well as supporting you and the employer before and after you've started work.

Making decisions

Someone with ASD may have the capacity to make some decisions (for example, to decide what items to buy at the local shop), but lack capacity to make other decisions (for example, making decisions about complex financial issues).

Where someone is judged not to have the capacity to make a specific decision after they've had a capacity assessment, that decision can be taken for them – but it must be in their best interests.

For more information, read What is the Mental Capacity Act?

Characteristics of autistic spectrum disorder

The characteristics of autistic spectrum disorder (ASD) can vary both from person to person and across different environments.

They can also be different for the same person at different times in their life. That is why autism is usually referred to as a spectrum disorder.

The traits of ASD can be divided into three main groups. They are:

  • social interaction
  • social communication
  • social imagination

The first characteristics of ASD can sometimes be seen in a child who is under the age of two. However, in other children the condition may not be picked up until they are much older.

Social interaction

A person who has ASD may find it hard to relate to other people. They may:

  • seem distant or detached
  • have little or no interest in other people
  • find it difficult to make friends
  • not seek affection in the usual way, or resist physical contact such as kissing and cuddling
  • find it difficult to make eye contact with other people
  • want to have social contact, but have difficulty knowing how to initiate it
  • not understand other people's emotions and have difficulty managing their own emotions
  • prefer to spend time alone

Social communication

A person who has ASD may have difficulty using verbal and non-verbal skills, and some people may remain non-verbal throughout their lives.

People with ASD who do speak may use speech in an overcomplicated way, using odd phrases or odd choices of words.

They may also make up their own words or phrases, and use more words than are necessary to explain simple things. Someone with ASD may also have difficulty:

  • expressing themselves well
  • understanding gestures, facial expressions or tones of voice
  • using gestures to communicate
  • understanding instructions

Some people with ASD may develop echolalia, where they repeat words that have little meaning or repeat what has been said to them.

Social imagination

Children with ASD may:

  • have limited imaginative play
  • play the same games over and over, or play with games designed for children younger than themselves
  • get upset if their daily routines are interrupted in any way
  • show repetitive behaviours, such as hand flapping or spinning

In addition, children and adults may also develop obsessions – for example, with specific objects, lists, timetables or routines.

Sensory difficulties

Most people with ASD also have sensory difficulties. This means they may be oversensitive to specific things, such as touch, certain textures, light levels, or sound.

Sensory difficulties can also lead to problems with movement. A person with ASD may appear clumsy or have an unusual way of walking.

Asperger syndrome

Asperger syndrome is another form of ASD. People with Asperger syndrome will generally not have a learning disability and are often of average or above average intelligence.

They will usually have fewer problems with language development, but may still experience difficulties with social communication.

Asperger syndrome is often diagnosed later in children, and sometimes their difficulties may not be recognised and diagnosed until adulthood. This can cause a delay in getting appropriate support for the individual and their family.

Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.