Diagnosis & Tests

In most cases, parents notice the symptoms of an autism spectrum disorder (ASD) when their child is around two years old. In some cases, mild symptoms of ASD may not be detected until adulthood.

Autism Spectrum Disorder - Diagnosing ASD in Children


If you are worried about your child's development, talk to your health visitor or visit your GP. Your GP may use a brief screening test, such as the Checklist for Autism in Toddlers (CHAT).

CHAT consists of a series of questions, such as:

  • Does your child take an interest in other children?
  • Does your child ever pretend, for example, to make a cup of tea using a toy cup and teapot, or pretend other things?
  • Does your child ever bring objects to show you?

Your GP may also carry out a series of exercises with your child, such as asking them to point out certain objects, or encouraging them to engage in imaginative play, such as pretending to make a cup of tea with a toy teapot.


If the results of the CHAT screening suggest that your child may have an ASD, you will be referred to a health professional who specialises in diagnosing ASD. They will make a more in-depth assessment.

This health professional may be:

  • A Psychologist – a health professional with training in psychology.
  • A Psychiatrist – a doctor with special training in psychology.
  • A Paediatrician – a doctor who specialises in treating children.

Some health boards now use multidisciplinary teams. These are made up of a combination of the professionals mentioned above as well as Speech & Language Therapists, Occupational Therapists, CAMHS professionals and Social Workers, who work together to carry out an assessment.

Assessment for ASD is a rigorous process that involves a number of detailed steps, which are explained below:

  • Any existing information about your child's development, health and behaviour will be sought from relevant people, such as your GP, nursery or school staff.
  • You will be asked to attend an appointment so that a detailed family history and the history of your child's development can be drawn up.
  • Your child will be asked to attend an appointment so that specific skills and activities can be observed and assessed. This is known as a focused observation. Focused observation looks at language, behaviour, the pattern of your child's thinking (known as their cognitive ability) and how they interact with others.
  • A detailed physical examination may be carried out, along with a series of tests, such as testing your child's blood for genetic conditions that are known to cause ASD.

Once this process is complete, an autism diagnosis can usually be confirmed or ruled out.

After Diagnosis

Parents may react in different ways when ASD has been confirmed. Some parents feel relieved because they now understand the reasons behind their child's behaviour and can begin to treat them.

Other parents feel an immense sense of shock and disbelief, as they are naturally worried about what the diagnosis means for their child's future.

A diagnosis of ASD is not a label that your child will be stuck with for the rest of their life. Rather, the diagnosis offers an insight into your child's individuality and personality. In turn, it gives you a chance to guide their development and growth.

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 (NAS) has an excellent range of resources and advice on its website. 


Scottish Autism also have a wide range of resources for young people and adults, including an on-line training programme for parents called 'Right Click'.

Diagnosis of ASD in Adults

Some people with Autism Spectrum Disorder (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.

Getting a diagnosis of Asperger syndrome or another condition on the autism spectrum will help people with the condition and their families understand ASD and decide what sort of support they need.

A diagnosis also means that the person will be classed as having a disability under the Disability Discrimination Act. This means that their employer (if they work) must make "reasonable adjustments" for them in the workplace, such as providing clear written instructions.

Once diagnosed, adults may be able to access autism-specific services, such as supported living services and social groups, if these are available in their area.  Services for adults are listed on the Autism Services Directory.

See your GP if you are concerned and ask them to refer you to a Psychiatrist or Clinical Psychologist.  The National Autistic Society website has information on the process of being diagnosed with ASD for adults.

If you're already seeing a specialist for other reasons, you may want to ask them for a referral instead. However, some health boards do not provide NHS funding for diagnosing ASD in adults.

Claiming Benefits

Some children with ASD can be entitiled to benefits, such as Disability Living Allowance. It's easier to apply for this once you have a clear diagnosis. Find out which benefits you may be entitled to on the National Autistic Society website.