Understanding Diagnosis

How we define conditions shapes how we treat people

The way a condition is defined - whether it is called a “disorder”, a “difference”, or a “disability” - has real consequences. It affects who gets diagnosed, what support they receive, and how they are treated by the people around them.

For neurodivergent people, this is not an abstract issue. The frameworks used to classify and diagnose conditions like ADHD, autism, dyslexia, and dyspraxia directly shape access to support, medication, workplace adjustments, and benefits - as well as how people understand themselves.

This section of the Advice Hub looks at the main frameworks for understanding disability and neurodivergence, the classification systems used by clinicians, and how these have changed over time.

Three models for understanding disability

There are three main frameworks for understanding disability and neurodivergence. Each one tells a different story about where the “problem” lies - and what should be done about it.

The medical model

The medical model views disability as something that exists within the individual. Under this model, conditions like autism or ADHD are seen as deficits to be treated, managed, or corrected.

In practice, this means the focus is on diagnosis, symptoms, and intervention - often with the aim of making the person function more like a neurotypical person. Many diagnostic manuals, including the DSM-5 and parts of the ICD-11, are rooted in this approach.

The medical model has value. It underpins the clinical evidence that leads to effective treatments, medication, and formal recognition of support needs. Without it, many people would not be able to access the care they need.

But it also has limitations. When the focus is entirely on what is “wrong” with the individual, wider factors - such as inaccessible environments, social exclusion, and systemic barriers - are ignored.

The social model

The social model of disability, first developed by disabled activists in the 1970s, reframes the issue. Rather than locating the problem within the person, it argues that people are disabled by barriers in society - not by their bodies or brains.

Under this model, a wheelchair user is not disabled by their inability to walk, but by buildings without ramps. An autistic person is not disabled by their need for routine, but by workplaces that refuse to accommodate it.

The social model has been hugely influential. It is the basis of the UN Convention on the Rights of Persons with Disabilities (CRPD) and underpins equality legislation in the UK and elsewhere.¹

The social model also has limitations. Some neurodivergent people experience genuine distress that would exist regardless of how well society is structured - executive dysfunction, sensory overwhelm, and emotional dysregulation can be deeply challenging even in the most supportive environment.

The neurodiversity paradigm

The neurodiversity paradigm builds on the social model but goes further. It holds that neurological differences - like ADHD, autism, dyslexia, and dyspraxia - are natural and valuable forms of human variation, not disorders to be cured.

This does not mean that neurodivergent people do not struggle, or that they do not need support. It means that the goal should be understanding and accommodation - not normalisation.

The neurodiversity paradigm has become increasingly influential in research, policy, and self-advocacy. It shapes how many neurodivergent people understand themselves and what they expect from services.

Classification systems

In clinical practice, two main systems are used to diagnose and classify mental health and neurodevelopmental conditions:

The DSM-5

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), published by the American Psychiatric Association, is the primary diagnostic manual used in the United States and in much psychiatric research worldwide. The most recent update is the DSM-5-TR (Text Revision), published in 2022.

The DSM-5 uses categorical diagnosis - you either meet the criteria for a condition or you do not. It has been criticised for its rigid boundaries, reliance on observable behaviour, and tendency to pathologise normal human variation.

Read more about the DSM-5

The ICD-11

The International Classification of Diseases, Eleventh Revision (ICD-11), published by the World Health Organization, is used internationally and is the standard for health reporting in most countries.

The ICD-11 introduced major changes in 2022, including a more dimensional approach to diagnosis - particularly for personality disorders and neurodevelopmental conditions. It allows dual diagnoses of ADHD and autism (which the ICD-10 did not), and takes a more lifespan-oriented view.

The UK NHS currently still uses ICD-10 as its mandatory classification system, though ICD-11 adoption is expected in the coming years.²

Read more about the ICD-11

Why frameworks matter for neurodivergent people

Different frameworks lead to very different experiences.

Under the medical model, an autistic person might be told they have “deficits in social communication” and offered behavioural therapy aimed at making them appear less autistic. Under the neurodiversity paradigm, the same person might be supported to understand their communication style, find environments that work for them, and access adjustments that reduce unnecessary strain.

Both diagnosis and support matter. But the framework behind them shapes whether a person leaves feeling understood - or pathologised.

How understanding has changed over time

The way we understand neurodivergence and mental health has changed dramatically over the past century. Conditions that were once ignored, misunderstood, or actively punished are now recognised as legitimate differences that deserve support.

Each condition covered in this Advice Hub has its own history of discovery, classification, and reclassification - from ADHD’s journey through “minimal brain dysfunction” to its current neurodevelopmental classification, to autism’s evolution from a rare childhood condition to a recognised spectrum across the lifespan.

Explore the history of any condition in the Advice Hub by looking for the “History” page within each section.

Further reading on neurobetter

• Neurodiversity - what it really means
• The language of neurodiversity
• Getting a diagnosis
• Late diagnosis
• Mental health and neurodivergence

neurobetter services

If you are trying to understand a diagnosis - or wondering whether to seek one - you do not have to do it alone.

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