AuDHD: autism and ADHD together, and how to get assessed

AuDHD is an informal name for having both autism and ADHD. It is not a diagnosis: diagnostic systems list autism and ADHD as two separate diagnoses, and a person can be given both. How often the two occur together depends on who is counted, and in England they mostly have separate assessment routes. This guide sets out what the official sources say, and where they stop.

This guide is general information, not medical advice, and it cannot tell you whether you have autism, ADHD or both: only a clinical assessment can. It does not cover treatment. We read the sources on 7 October 2026. NHS website pages describe England, NICE says its guidelines are for England and Wales, and we say which nation each source covers.

What does AuDHD mean?

The National Autistic Society (NAS) says it is quite common for autistic people to also receive an ADHD diagnosis, and that this is “sometimes referred to as ‘AuDHD’”.

We read the NICE guidelines on ADHD and autism and the information and guidance pages listed in Sources from the NHS website, NHS England, the Royal College of Psychiatrists (RCPsych), GOV.UK, NHS inform, NHS 111 Wales and nidirect, and none of them uses the word. Where they describe the overlap they use other wording, such as “coexisting” conditions in NICE’s guidelines, or, on the NHS website, that ADHD “is also more common in autistic people”.

The word is also recent in research. A title-or-abstract search of PubMed for “AuDHD” on 7 October 2026 returned 15 records, all dated 2024 to 2026. One interview study (published online in April 2025) of six women diagnosed in adulthood describes a combined autism and ADHD diagnosis as “a residual category not formally represented in diagnostic systems”.

The two conditions are formally separate diagnoses. The American Psychiatric Association’s DSM-5 fact sheet on ADHD says DSM-5 “includes no exclusion criteria for people with autism spectrum disorder, since symptoms of both disorders co-occur”. The World Health Organization’s ICD-11 guidance says the two “can co-occur, and both diagnoses may be assigned if the diagnostic requirements for each are met”, and calls co-occurrence “common”. A 2020 UK expert consensus on ADHD and autism together, covering children and adults, says autism “is no longer an exclusion criterion, which is a fundamental change from DSM-IV” for an ADHD diagnosis.

How often do autism and ADHD occur together?

Direction matters, because “how many autistic people have ADHD” and “how many people with ADHD are autistic” are different questions with different answers.

• ADHD among autistic people. A 2019 meta-analysis in The Lancet Psychiatry (Lai and colleagues) included studies that reported confirmed DSM or ICD diagnoses. Its pooled estimate was that 28% (95% confidence interval 25 to 32) of autistic people had ADHD. Estimates were higher in studies of clinical samples than in population-based and registry-based studies, and substantial variation between studies remained unexplained.
• Autism among people with ADHD. A 2020 meta-analysis of 22 publications (Hollingdale and colleagues, Psychological Medicine) found that 21% of children and adolescents with ADHD met a threshold for autism, mostly on screening questionnaires rather than diagnostic assessments (13 of its 22 included publications fed that figure). It covers children and adolescents only. We found no meta-analysis of autism among adults with ADHD.

You may see “50 to 70%” quoted for ADHD in autistic people. The only source we read for it is a 2022 opinion article, which attributes the figure to the literature and says reported rates range from 10 to 90%. We did not find a UK figure for adults who have both conditions among the sources we read.

How do autism and ADHD overlap, and how do they differ?

The WHO’s ICD-11 guidance says attention abnormalities (such as being overly focused or easily distracted), impulsivity and physical hyperactivity “are often observed” in autistic people, and that people with ADHD “do not exhibit the persistent deficits in initiating and sustaining social communication and reciprocal social interactions” that define autism. It adds that ADHD symptoms “may sometimes dominate the clinical presentation such that some autism spectrum disorder symptoms are less apparent”.

The NHS website says it may be difficult to see signs of autism if an adult has other conditions, including ADHD. NHS inform says people with one diagnosis may also have traits of other neurodevelopmental conditions, and RCPsych says many of the traits of autism exist in people who are not autistic, or who have other conditions. A UK consensus says both conditions are commonly associated with social difficulties, executive dysfunction and language and cognitive delays.

These descriptions are written for clinicians, so they are not a test you can apply to yourself. Screening questionnaires do not diagnose either: RCPsych says you could get a high score on the autism screening questionnaire, the AQ, “if you have another neurodevelopmental condition or a mental health condition”. For assessors, the UK consensus says they should “not ‘double count’ symptoms present in both ADHD and ASD”, and that because co-occurrence is high, both conditions should be considered when one is present.

Masking, and why either condition can be missed

The NHS website says adults may have learned to adapt so that signs of autism are not always noticeable, and calls this masking. NAS defines masking as “a strategy used by some autistic people, consciously or unconsciously, to appear non-autistic”, says it can have “a devastating impact on mental health, sense of self and access to an autism diagnosis”, and says of how common it is: “We don’t know.” NAS adds that there are no formal clinical assessment tools for masking, and that health care professionals should be aware that autistic people may be masking.

One pre-registered study of adults that used a Dutch-language questionnaire (van der Putten and colleagues, 2024) found that adults with ADHD also showed camouflaging, though not as much as autistic adults. Its questionnaire measures camouflaging of autistic traits, so comparison across the two conditions is limited. We found no source saying masking is more common in people who have both.

Both conditions may be missed or recognised late in women. RCPsych says “It is likely that autism is underdiagnosed in women and girls”, the NHS website says ADHD is thought to be recognised less often in women than men, and NAS says women and girls may be misdiagnosed with mental health issues, or have their autistic traits missed amid the symptoms of co-occurring conditions. A UK consensus says girls may be consistently under-identified for both ADHD and autism.

Research on women with both is thin: the two papers of this kind that we read are by the same author and appear to describe the same six women, in a small qualitative study based on email interviews. For more on ADHD, see our guide to ADHD in women.

How are autism and ADHD assessed in England?

The NHS website describes two routes that both start with a GP. For autism it says GPs can often refer children and adults to a local autism team, and that you may also be referred for an autism assessment when you are getting help for another condition. For adult ADHD it says the GP may decide to refer you for an assessment with a mental health professional specialising in ADHD, and may also want to consider other conditions that could be causing your symptoms, such as autism.

If you find it hard to get a referral for an autism assessment, the NHS website says you could ask to speak to someone else, like another GP.

Both NICE guidelines expect coexisting conditions to be considered. NICE’s guideline on autism in adults says a comprehensive assessment should enquire about and assess other neurodevelopmental conditions, and should take into account possible coexisting conditions. NICE’s ADHD guideline says the diagnostic process should include an assessment of coexisting conditions. NICE says its guidelines are for England and Wales.

That is not the same as one combined assessment. The ADHD Taskforce commissioned by NHS England said in its interim report (published in June 2025) that ADHD, autism and other neurodevelopmental services in England “are often separated and siloed by diagnosis type and by age”, and recommended a single front door for ADHD, co-occurring neurodevelopmental conditions and mental health; its final report repeats the front-door recommendation. A recommendation is not current practice, and NHS England has said it will review the recommendations in the final report with colleagues across Government.

We found no NHS website or NICE page describing a combined autism and ADHD assessment route for adults in England. NHS England’s 2026/27 payment guidance for commissioners lists a combined adult ADHD and autism assessment, and its operational guidance on autism assessment pathways (updated 22 July 2026) says an autism assessment is sometimes done jointly with clinicians from another service, such as an ADHD assessment service. Neither says which local services offer a combined assessment. The only mention of joint assessment for both conditions that we found in NICE’s guidelines is in a rationale about children and young people.

How long you wait varies. RCPsych’s page, published in November 2024, says waiting times for autism assessments vary across the UK and “in some places can be 12 months or longer”.