How to get an autism diagnosis in the UK

The hardest part is often not knowing what happens next, or fearing you’ll have to prove something. Plenty of adults and parents put off asking about autism because nobody has told them what the process involves. You don’t need to arrive with answers, only with your own experience. This guide sets out each step plainly, so you can choose a route knowing what’s involved.

What does an autism diagnosis look for?

An autism diagnosis looks for a pattern that has run through your whole life. Under NICE guidance on autism in adults, the assessment covers two core areas [1]. One is difficulty with social interaction and communication. The other is repetitive behaviour, resistance to change or restricted interests, present since childhood and continuing into adulthood [1]. So the question is whether these differences have always been there, not whether you’ve had a hard month.

Clinicians ask about the wider signs of autism too, including sensory sensitivities and other conditions [1]. Your early development matters where it can be traced, as does daily life at home, in education or at work [1]. The core features are also observed directly, especially in social situations [1]. Everything is then weighed together with clinical judgement [2].

What are the routes to an autism diagnosis in the UK?

There are two ways in, through the NHS or privately, and the table shows four common routes. Whichever you choose, it should end in the same kind of specialist assessment.

Under Right to Choose for autism, your GP in England can usually refer you to a service you pick [4].

How do you get an autism diagnosis on the NHS?

On the NHS, the route usually starts with your GP. GPs can often refer adults and children to a local autism team [3]. A mental health professional who notices signs of autism while helping you with something else can also suggest a referral [3]. So it’s worth mentioning autism to any service you’re already seeing. If a referral is hard to get, you can ask to speak to someone else, such as another GP [3].

Children’s referrals can look a little different. For under-18s, the NHS provides or funds children and young people’s mental health services, often called CAMHS [5]. Services differ by area [5], and your GP can refer your child to the local autism team [3]. NICE says each area should have one place where children’s autism referrals go [2]. Scotland has its own guideline on autism, from SIGN [6].

What are the diagnostic criteria for autism?

A UK diagnosis is made against the criteria in one of two manuals, DSM-5 or ICD-11 [2]. DSM-5 is the American psychiatric manual, and it describes autism spectrum disorder through five points [7]:

• lasting differences in social communication and social interaction.
• restricted, repetitive patterns of behaviour, interests or activities.
• signs present in early development.
• signs that cause real difficulty in daily life, such as at work or with friends.
• differences not better explained by intellectual disability or global developmental delay.

ICD-11, the World Health Organization’s classification, sets out the same two core areas, starting in early childhood [7]. It adds that some characteristics might not fully show until later in life, when social demands increase [7]. That’s one reason some people aren’t recognised as autistic until adulthood. Both manuals now use the single term autism spectrum disorder, so Asperger’s syndrome is no longer a separate diagnosis [7]. DSM-5 also describes levels of support, which our guide to types and levels of autism explains.

What tools do clinicians use, such as the ADOS-2 and ADI-R?

Clinicians use structured tools to keep the method consistent, but no single tool settles the question [7]. The ADOS-2, the second edition of the ADOS, is a standardised, semi-structured observation of communication, social interaction, imagination and repetitive behaviours [8]. Our adult autism assessment doesn’t use the ADOS-2 as standard, but you can ask for it. It’s a guided session where a clinician watches how you communicate and interact. Its modules are matched to age and spoken language, and Module 4 is for older teenagers and adults who speak fluently [8]. The second edition also added a toddler module [8].

The ADI-R takes a different approach. The Autism Diagnostic Interview, Revised, is interview-based, and it’s suggested for both children and adults [7]. For more complex adult assessments, NICE lists the ADI-R, the ADOS, the RAADS-R and the Adult Asperger Assessment [1]. Not every assessment uses them. Short questionnaires such as the AQ-10 are screens that can lead to an assessment, not a diagnosis [1]. An online ASD test works the same way.

What happens in the appointments for adults?

You might have one appointment or several, with clinicians from different professions [3]. The aim is to understand your whole life, so they may ask for any of these [3]:

• questionnaires to fill in about yourself.
• an account of how you get on with other people.
• your early life, and your life at home, at work or in study.
• GP reports, school reports or assessments from work.

Where possible, the people assessing you should also involve someone who knows you, such as a partner, family member or carer [1]. At the start, the clinicians should explain what the assessment is for and how you’ll hear the outcome [1]. Our clinicians find that masking, meaning hiding or working around your differences, is common in adults who’ve compensated for years. It helps to bring real examples from different parts of your life, and old school reports if you still have them.

How is autism diagnosed in a child?

For a child, the diagnosis comes from a multidisciplinary team, meaning people from several professions working together [2]. Its core members should include a paediatrician or child and adolescent psychiatrist, a speech and language therapist and a psychologist [2]. As a parent, you’re a big part of the picture. Every child’s assessment should cover these points, among others [2]:

• your concerns, and your child’s own where that’s right.
• your child’s home life, education and any social care.
• your child’s developmental history, from the early months on.
• how your child communicates and gets on with others, observed directly.
• a medical history and a physical examination.

The findings should then be explained to you and, where right, to your child [2]. At AuDHD Psychiatry, our assessment for children covers ages 6 to 17, and a parent can be present during their child’s assessment. It has three appointments: an ADOS assessment with your child, an autism-focused interview with your child, and an interview with someone who knows them.

What else do clinicians rule out or look for?

A careful assessment also looks for other explanations, and for conditions that can sit alongside autism [1]. The list includes other neurodevelopmental conditions, mental health conditions, epilepsy and other neurological conditions, and speech and language difficulties [1]. Getting this right matters, because the full picture shapes what support makes sense afterwards. Blood tests, genetic tests and brain scans aren’t used routinely to diagnose autism, as NICE advises against them [1].

ADHD is also a neurodevelopmental condition, and some people have both. If that sounds familiar, an assessment for ADHD and autism together looks at the two side by side. Mention any diagnosis you’ve had before, even one that never quite fitted.

What if you want a private diagnosis?

A private team should work to the same NICE standard as an NHS one [1]. Check that trained professionals work together and involve someone who knows you where possible [1].

A private assessment may suit you if:

• you’re 18 or over, or your child is 6 to 17.
• you want to go direct, without a GP referral.

It might not be right today if:

• you need urgent help now. Call NHS 111 and choose the mental health option, or in Northern Ireland call Lifeline free on 0808 808 8000, any time. In an emergency, call 999 or go to A&E [9].
• your child is under 6.

AuDHD Psychiatry assesses adults and children online. Our private autism assessment for adults has two appointments, one an interview with someone close to you. If nobody can take part, we can still assess you. An outcome letter follows the next day, and the full report within two weeks. For children, see our autism assessment for children. A free 15-minute call can come first, for information rather than an assessment.

What happens after an autism diagnosis?

After an NHS assessment, you’ll get a report saying whether you or your child are autistic [3]. The report also covers strengths, what help might be useful, and any other conditions found [3]. You may be offered a follow-up appointment, plus a care plan or information on autism support and treatment [3]. Our guide to benefits and support for autistic people covers what else may be open to you.

If you don’t agree with the result, start by asking the clinicians how they reached it [3]. After that, your GP or the assessing service can refer you elsewhere for a second opinion, or you can pay privately [3].

Questions people ask

In short

Autism is diagnosed by clinicians who weigh your history, observation and other people’s accounts against DSM-5 or ICD-11. You can begin through your GP, or go privately without a referral. Either way, a written report follows, and support can be built around what it finds. If you’d like AuDHD Psychiatry to look at the full picture with you, our assessment pages set out what’s involved.