Autism in adults: signs, diagnosis and support

Key points

• Autism is a lifelong difference in how the brain develops, not an illness, and is not treated or cured [2].
• More than one in 100 people are autistic, and at least 700,000 autistic adults and children live in the UK [5].
• Diagnosis is made by a specialist autism team after a detailed assessment, usually via a GP referral [1][4].
• In England 294,792 people of all ages had an open autism referral in June 2026, and 86.8% had waited at least 13 weeks [8].
• Masking hides autistic traits, and many autistic women and other late-diagnosed adults were missed because of it [3][7].

What autism is

Autism is a lifelong difference in how the brain develops that shapes how a person communicates, thinks, and takes in light, sound, smell, taste and touch [2]. In adults it is often recognised late, after years of finding social situations, change or busy places hard. Autism is not an illness, and there is no treatment or cure [2].

If you need help now. Samaritans: call 116 123, free, 24/7. Shout: text 85258. NHS 111, then choose the mental health option. Call 999 if anyone is in immediate danger.

More than one in 100 people are autistic, and at least 700,000 autistic adults and children live in the UK, on research estimates rather than diagnosis counts [5].

Autism is not a learning disability or a mental health condition, though about a third of autistic people also have a learning disability, and anxiety, depression and ADHD are more common [2][5].

Symptoms

Autism is described through characteristics, not deficits. No autistic person shows all of them.

Social communication and interaction [3] - Finding conversation effortful or confusing. - Reading facial expressions, gestures or tone of voice differently. - Taking language literally, so a phrase like “it’s a piece of cake” is hard to place.

Routine, repeated behaviour and interests [3][5] - Fixed ways of doing things, and distress when routine changes. - Repeated movements such as rocking or hand flapping, called stimming, used to stay calm. - Focused, dedicated interests held in unusual depth.

Sensory differences [5] - Being much more, or much less, sensitive to light, sound, smell, taste or texture.

In adults, autism is often confused with, or hidden behind, social anxiety disorder, obsessive compulsive disorder, depression, eating disorders and ADHD [1][3].

Types

Autism no longer has separate named subtypes. It is recorded as one diagnosis, autism spectrum disorder [2]. Asperger syndrome became official in ICD-10 in 1992 and DSM-IV in 1994. It was retired in DSM-5 in 2013 and ICD-11 in 2019 and folded into that single diagnosis [6].

For someone holding an older diagnosis: - An existing Asperger syndrome diagnosis still describes the same profile, now recorded under the single autism diagnosis [6]. - Some people still use the older term for themselves. Others avoid it, because of what is now known about Hans Asperger’s role during the Nazi era [6].

The spectrum is not a line from mild to severe: each autistic person has a different mix of characteristics [5].

Causes and risk factors

There is no single cause of autism and no test that identifies one. Evidence points to genetics, probably many genes rather than one, and autism sometimes runs in families [2][5].

Explanations the evidence does not support: - Vaccines do not cause autism, which has been studied repeatedly [2][5]. - Paracetamol does not cause autism [5]. - Parenting style does not cause autism, and autism cannot be acquired later [5].

Autism is present from birth, so an adult diagnosis means the characteristics were there in childhood and missed [1].

How it is diagnosed

An autism diagnosis in adults is made by a specialist autism team, not one clinician: NICE recommends each area has a community based multidisciplinary team of psychologists, psychiatrists, nurses and therapists [1].

The NHS route starts with a GP, who can refer an adult to the local autism team; a mental health professional can also refer [4]. NICE suggests the Autism Spectrum Quotient 10 items (AQ-10) first: a score of 6 or above, or clinical judgement, leads to a full assessment [1].

That assessment normally involves: - Questions about early life, home, work, routines, interests and sensory sensitivity [1][4]. - Observation of social interaction [1]. - Speaking to someone who knew the person as a child, and reading school or workplace reports [1][4]. - A structured tool such as ADOS-G, ADI-R, DISCO or RAADS-R where the picture is complex [1].

Blood tests and brain scans are not used; a written report and follow-up appointment follow [1][4].

NHS England Digital recorded 294,792 people of all ages in England with an open referral for suspected autism in June 2026, of whom 86.8% had waited at least 13 weeks, the maximum NICE recommends [8]. Right to Choose lets people in England ask for a different NHS or approved provider, often a shorter wait [4].

Many autistic women, and many autistic adults generally, are diagnosed late or misdiagnosed. Stereotypes about who can be autistic play a part, as do tools built around traits more common in men and boys. Masking hides those traits, so distress is more often labelled anxiety or depression [3][7].

Treatment

Autism itself is not treated. NICE recommends no medication for the core features of autism, and advises against antipsychotics, antidepressants, anticonvulsants, oxytocin, chelation, exclusion diets and supplements for that purpose [1]. What follows is about support, adjustments and treating co-occurring conditions.

NICE recommends considering social learning programmes, structured leisure programmes for isolated adults, skills training for daily living, adapted anger management, and supported employment schemes advising employers [1].

For a co-occurring mental health condition, NICE says to follow the standard guidance for it, delivered by staff who understand autism [1]. Cognitive and behavioural therapy should be adapted: more written and visual material, more focus on behaviour than thoughts, explicit rules, plain English and regular breaks [1]. NICE warns that autistic people can be more sensitive to medication side effects [1]. Decisions about medication rest with a GP or prescriber.

Most NICE recommendations here say consider rather than offer, reflecting small trials rather than proven benefit.

Living with autism

Masking. Masking means hiding autistic traits to fit in, by copying others, suppressing stimming or rehearsing social scripts [3][9]. It makes ordinary activities exhausting, and sustained masking is described as a contributor to autistic burnout [9].

Autistic burnout. Research describes autistic burnout as long-term exhaustion, loss of skills and reduced tolerance of sensory input, typically lasting three months or more, after sustained stress and demands that exceed your capacity [9]. What helped in that research: cutting the load, adjustments at work, time with people who accept you unmasked, and learning your early warning signs [9].

Sensory needs. NICE asks services to adjust the environment, and the same changes help at home and at work: less fluorescent lighting, lower noise or ear defenders, and plain surroundings [1].

Work and the Equality Act 2010. Autistic people are protected as disabled under the Equality Act 2010, so employers must make reasonable adjustments so you are not put at a disadvantage compared with non-disabled colleagues [10]. Common ones are written instructions, agendas in advance, a quieter desk and changed hours. You need not tell an employer, but the duty applies once they know.

When to speak to a professional

Speak to a GP if you recognise these characteristics in yourself and want an assessment. The GP can refer you, say what support exists while you wait, and discuss Right to Choose. If refused, ask another GP for a second opinion [4].

Speak to a GP sooner if: - Low mood, anxiety or exhaustion has lasted weeks and is affecting work or relationships. - You have lost skills you previously had, such as cooking or leaving the house. - You are not eating or sleeping properly, or are withdrawing from everyone.

Get help now if you are thinking about harming yourself or ending your life. Call Samaritans free on 116 123, text SHOUT to 85258, or call NHS 111 and choose the mental health option. Call 999 if anyone is in immediate danger.

Common questions

Can you be autistic and not know until adulthood?

Yes, and it is common. Autism is present from birth but can go unrecognised for decades, particularly where someone has masked or been given another diagnosis instead [3][7].

Is Asperger syndrome still a diagnosis?

No. It was retired from DSM-5 in 2013 and ICD-11 in 2019 and folded into autism spectrum disorder, though an existing diagnosis stays valid [6].

How long is the wait for an NHS autism assessment?

Longer than the 13 weeks NICE recommends: at June 2026, 86.8% of people in England with an open referral had waited at least that long [8]. Waits vary by area, and Right to Choose may allow a move to a shorter list [4].

What is autistic burnout?

A long period of exhaustion, loss of skills and reduced tolerance of noise, light and social contact, described in research as lasting three months or more after sustained stress without enough support [9]. The term came from autistic people rather than diagnostic manuals, and the research is small.

Clinical review pending

References

1. National Institute for Health and Care Excellence. Autism spectrum disorder in adults: diagnosis and management. Clinical guideline CG142, published 2012, last updated 2021. https://www.nice.org.uk/guidance/cg142
2. NHS. What is autism? 2026. https://www.nhs.uk/conditions/autism/what-is-autism/
3. NHS. Signs of autism in adults. 2026. https://www.nhs.uk/conditions/autism/signs/adults/
4. NHS. Autism assessments. 2026. https://www.nhs.uk/conditions/autism/getting-diagnosed/how-to-get-diagnosed/
5. National Autistic Society. What is autism? 2026. https://www.autism.org.uk/advice-and-guidance/what-is-autism
6. National Autistic Society. Asperger syndrome. 2026. https://www.autism.org.uk/advice-and-guidance/what-is-autism/the-history-of-autism/asperger-syndrome
7. National Autistic Society. Autistic women and girls. 2026. https://www.autism.org.uk/advice-and-guidance/what-is-autism/autistic-women-and-girls
8. NHS England Digital. Autism Statistics, July 2025 to June 2026. 2026. https://digital.nhs.uk/data-and-information/publications/statistical/autism-statistics/july-2025-to-june-2026
9. National Autistic Society. Autistic burnout, by Dr Dora Raymaker. https://www.autism.org.uk/advice-and-guidance/professional-practice/autistic-burnout
10. GOV.UK. Disability rights: employment. https://www.gov.uk/rights-disabled-person/employment