The ICD-11
What is the ICD-11?
The International Classification of Diseases (ICD) is the global standard for classifying health conditions. Published by the World Health Organization (WHO), it is used for clinical diagnosis, health reporting, and research across most of the world.
The ICD-11 was adopted by the World Health Assembly in May 2019 and came into effect for international health reporting in January 2022. It replaces the ICD-10, which had been in use since 1990.1
UK status
The NHS in England currently still uses ICD-10 as its mandatory classification system. No firm date has been set for ICD-11 adoption, though NHS Digital has been involved in field trials. Until the transition happens, clinicians in the UK may reference both systems.2
What has changed from ICD-10 to ICD-11
The ICD-11 introduces some of the most significant changes to mental health and neurodevelopmental classification in decades. Several of these changes have direct relevance for neurodivergent people.
Neurodevelopmental disorders come first
In the ICD-11, neurodevelopmental disorders are the first main category in the mental health chapter - ahead of all other psychiatric conditions. In the ICD-10, they were scattered across three different chapters.3
This reflects a growing recognition that neurodevelopmental conditions are foundational - they affect how a person develops from early life and shape their experience of everything else, including mental health.
The neurodevelopmental disorders chapter in ICD-11 includes:
- Autism spectrum disorder
- Attention deficit hyperactivity disorder
- Disorders of intellectual development
- Developmental speech or language disorders
- Developmental learning disorders (including dyslexia and dyscalculia)
- Developmental motor coordination disorder (dyspraxia/DCD)
- Tic disorders (including Tourette syndrome)
- Stereotyped movement disorder
Autism: one spectrum, not multiple categories
The ICD-10 listed eight separate pervasive developmental disorders, including childhood autism, atypical autism, and Asperger syndrome. The ICD-11 replaces all of these with a single category: autism spectrum disorder (ASD).3
This change acknowledges that autism is a spectrum - not a collection of distinct conditions. Qualifiers are provided for the level of impairment in intellectual functioning and functional language abilities, allowing clinicians to capture the full range of presentations without relying on outdated subcategories.
Gender recognition
The ICD-11 explicitly acknowledges that women and girls with autism often present differently - with better surface-level social skills, less obvious behaviours, and more effective camouflaging. This means they are frequently missed or diagnosed later. The ICD-11 underscores this more strongly than previous editions.3
The age of onset requirement has also been broadened. Rather than specifying onset by age 3, the ICD-11 states that features must be present in the “early developmental period” - recognising that traits may not become apparent until social demands increase.3
ADHD replaces hyperkinetic disorder
The ICD-10 used the term “hyperkinetic disorders.” The ICD-11 replaces this with attention deficit hyperactivity disorder (ADHD), aligning with the DSM-5 and with common clinical usage.3
ADHD has been moved into the neurodevelopmental disorders grouping and can now be characterised as predominantly inattentive, predominantly hyperactive-impulsive, or combined type. It is described across the lifespan, recognising that ADHD does not simply disappear in adulthood.
The age criterion has been raised from 5 years (ICD-10) to 12 years, acknowledging that symptoms may not become clear until later in development.
ADHD and autism can now be diagnosed together
Under the ICD-10, a dual diagnosis of ADHD and autism was not permitted. This was a significant problem, because research consistently shows that the two conditions frequently co-occur.
The ICD-11 removes this exclusion. ADHD and autism can now be recognised as co-existing conditions - an important change for people who have both.3
Why this matters
Research shows that autistic people with co-occurring ADHD can benefit from stimulant medications. Under the old system, the inability to diagnose both conditions meant many people were denied appropriate treatment.3
Personality disorders: a new dimensional model
One of the most radical changes in the ICD-11 is to personality disorder classification. The ICD-10 had ten separate categories of personality disorder (including emotionally unstable personality disorder, or what the DSM calls borderline personality disorder). The ICD-11 replaces all of these with a single diagnosis of personality disorder, specified by severity and trait domains.4
Under the new model:
- Severity is classified as mild, moderate, or severe
- Five trait domains can be specified: negative affectivity, detachment, dissociality, disinhibition, and anankastia
- A borderline pattern qualifier was retained after extensive debate, primarily to ensure continuity of access to specialist treatments
This dimensional approach recognises that personality difficulties exist on a continuum and that the old categorical system created artificial boundaries, excessive comorbidity, and stigma.4
What this means for neurodivergent people
The ICD-11 explicitly states that autism spectrum disorder should generally take precedence over personality disorder in differential diagnosis. A personality disorder diagnosis should only be given alongside autism if there are features that cannot be accounted for by autism and its common co-occurring conditions.5
This is a critical safeguard. It directly addresses the well-documented problem of autistic people - particularly women - being misdiagnosed with personality disorders when their difficulties are better explained by unrecognised autism.
Read more about personality disorders and neurodivergence
Critical perspectives
The ICD-11 represents significant progress, but it is not without criticism.
Vague criteria
Some researchers have argued that the ICD-11’s criteria for autism spectrum disorder allow a high variety of symptom combinations, which may increase diagnostic sensitivity but at the expense of precision. This has raised concerns about the potential for false positive diagnoses and further increases in prevalence rates.6
Implementation challenges
Transitioning from ICD-10 to ICD-11 is a major undertaking for health systems. Many countries - including the UK - have been slow to adopt the new system. This means that in practice, many clinicians are still working with ICD-10 criteria, even though ICD-11 has been in effect internationally since 2022.
The borderline pattern debate
The inclusion of the borderline pattern qualifier in the personality disorder section was controversial. Some researchers have argued that borderline criteria do not form a separate construct and are inseparable from the negative affectivity trait domain, meaning the qualifier adds complexity without adding clinical value.4
How the ICD-11 compares to the DSM-5
| Feature | ICD-11 | DSM-5 |
|---|---|---|
| Publisher | World Health Organization | American Psychiatric Association |
| Primary use | International health reporting, UK clinical coding | US clinical practice, research worldwide |
| Approach | More dimensional, especially for PD | Primarily categorical |
| Autism subtypes | Single ASD category with qualifiers | Single ASD category with support levels |
| ADHD + autism | Dual diagnosis allowed | Dual diagnosis allowed (since DSM-5) |
| Personality disorders | Single diagnosis with severity + trait domains | Retains categorical types (with alternative dimensional model in Section III) |
| ASD vs PD guidance | Explicitly states ASD overrules PD | Less explicit on precedence |
| UK status | Not yet adopted by NHS | Used alongside ICD in UK clinical practice |
What this means for you
If you are seeking diagnosis or have been diagnosed, understanding the ICD-11 can help you:
- Know which system was used - ask your assessor whether they used ICD-10, ICD-11, or DSM-5 criteria
- Understand your report - knowing the difference between “hyperkinetic disorder” (ICD-10) and “ADHD” (ICD-11) can make reports less confusing
- Challenge a misdiagnosis - if you believe a personality disorder diagnosis may be masking unrecognised autism, the ICD-11’s guidance on differential diagnosis supports that conversation
- Prepare for change - when the UK adopts ICD-11, diagnostic language and pathways may shift
The system is catching up
For many neurodivergent people, formal classification systems have been slow to reflect what they already know about their own experiences. The ICD-11’s changes - while imperfect - represent real progress in how neurodevelopmental conditions are understood and diagnosed.
Further reading on neurobetter
- Understanding diagnosis - overview
- The DSM-5
- Personality disorders and neurodivergence
- Getting a diagnosis
- Co-occurrence of neurodivergent conditions
neurobetter services
- Local services directory - find assessment and support services near you
- Online community - connect with others navigating diagnosis
- Ask a Counsellor - get a confidential response from a registered counsellor
If you are in crisis
If you are struggling right now, please visit our Get Help Now page for immediate support options, including Samaritans (116 123), Crisis Text Line (text SHOUT to 85258), and NHS 111.
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World Health Organization. (2019). ICD-11: International Classification of Diseases 11th Revision. https://icd.who.int/en ↩
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NHS Digital. (2023). Preparations for the implementation of ICD-11. https://digital.nhs.uk/about-nhs-digital/essential-information-and-alerts-for-stakeholders/essential-information-for-technology-suppliers/preparations-for-the-implementation-of-icd-11 ↩
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Salvador-Carulla, L. et al. (2023). Neurodevelopmental disorders in ICD-11 classification. European Psychiatry, 66(S1), S156. https://doi.org/10.1192/j.eurpsy.2023.383 ↩
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Bach, B. and First, M.B. (2018). Application of the ICD-11 classification of personality disorders. BMC Psychiatry, 18, 351. https://doi.org/10.1186/s12888-018-1908-3 ↩
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Kamp-Becker, I. et al. (2023). Differential Diagnosis of ICD-11 Personality Disorder and Autism Spectrum Disorder in Adolescents. Children, 10(6), 992. https://doi.org/10.3390/children10060992 ↩
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Kamio, Y. et al. (2023). Autism spectrum disorder in ICD-11 - a critical reflection of its possible impact on clinical practice and research. Molecular Psychiatry, 28, pp. 4440-4448. https://doi.org/10.1038/s41380-023-02354-y ↩
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