What is neurodivergence?
Neurodivergence describes a difference in the way someone's brain develops, processes information and experiences the world.
The term is commonly used to describe people whose neurological development differs from what is considered typical, including people with conditions such as autism, ADHD, dyslexia, dyspraxia and Tourette syndrome.
Neurodivergence is not itself a medical diagnosis. It is an umbrella term used to describe a range of neurological and developmental differences. There is no single, universally agreed list of conditions that are considered neurodivergent.
What is neurodiversity?
Neurodiversity is the idea that there is natural variation in how human brains develop and function.
The term is sometimes used interchangeably with neurodivergence, but they mean different things.
Neurodiversity describes the variation across the whole population – just as biodiversity describes variation among living things.
Neurodivergence describes an individual whose neurological development differs from the majority.
Neurodivergent people can experience significant challenges, disabilities and barriers, but may also have particular strengths. The experience varies enormously from person to person, even among people with the same diagnosis.
Many neurodivergent conditions can also co-occur. For example, someone can be autistic and have ADHD, or have both dyslexia and dyspraxia. Some people, for example, identify as AuDHD.
Common types of neurodivergence
There is no definitive list, but the following conditions are commonly described as forms of neurodivergence.
Autism
Autism, or autism spectrum disorder (ASD), is a neurodevelopmental condition that affects how a person communicates and interacts with other people; and how they experience and respond to the world.
Autistic people may experience differences in social communication and interaction, alongside restricted, rigid, or repetitive patterns of behaviour, interests or activities. Sensory differences are also common.
Diagnostic criteria
Under DSM-5-TR criteria, an autism diagnosis requires:
Persistent differences in social communication and social interaction across contexts;
Restricted or repetitive patterns of behaviour, interests or activities, with at least two specified types present;
Characteristics that were present in the early developmental period, even if they were not recognised until later;
Characteristics that cause clinically significant difficulties in social, occupational or other important areas of functioning; and
The characteristics not being better explained by intellectual disability or global developmental delay.
Autism is assessed through a detailed clinical assessment rather than a single test.
ADHD
Attention Deficit Hyperactivity Disorder (ADHD) affects attention, activity levels and impulse control. People with ADHD may experience difficulties with concentration, organisation, working memory, managing time, regulating attention and controlling impulses.
ADHD can present predominantly through inattentive symptoms, predominantly through hyperactive/impulsive symptoms, or through a combination of both.
Diagnostic criteria
For an ADHD diagnosis, a persistent pattern of symptoms of inattention and/or hyperactivity-impulsivity must:
Interfere with functioning or development;
Include a sufficient number of symptoms for the person's age;
Have been present from childhood, with several symptoms occurring before age 12;
Occur across more than one setting, such as home, education or work; and
Not be better explained by another condition.
For adults, clinicians also consider the person's childhood history and how symptoms affect areas such as work, relationships and everyday life.
Dyslexia
Dyslexia is a specific learning difficulty primarily associated with difficulties with accurate and fluent reading and spelling. It can also affect phonological processing, working memory and aspects of written language.
Dyslexia is generally considered under the broader diagnostic category of Specific Learning Disorder (SLD) in DSM-5-TR.
Diagnostic criteria
A diagnosis of Specific Learning Disorder requires persistent difficulties in at least one academic area – reading, written expression or mathematics – despite appropriate support.
The difficulties must:
Have persisted for at least six months;
Be substantially below what would be expected for the person's age;
Interfere with academic, occupational or everyday functioning;
Have their origins during the school years; and
Not be better explained by intellectual disability, uncorrected sensory difficulties, neurological conditions, lack of appropriate education or difficulties with the language of instruction.
Dyslexia corresponds broadly to Specific Learning Disorder with impairment in reading.
Dyscalculia
Dyscalculia is a term commonly used to describe persistent difficulties with understanding and working with numbers and mathematical concepts.
It can affect areas such as number sense, learning arithmetic facts, calculation and mathematical reasoning. Like dyslexia, it falls under Specific Learning Disorder in DSM-5-TR.
Diagnostic criteria
The underlying diagnostic criteria are those for Specific Learning Disorder, with impairment in mathematics.
This means persistent mathematical difficulties must significantly affect academic, occupational or everyday functioning, have begun during the developmental period and not be better explained by other factors.
Dysgraphia
Dysgraphia is commonly used to describe significant difficulties with written expression, including handwriting, spelling and the organisation of written work.
Terminology varies between diagnostic systems. In DSM-5-TR, difficulties with written expression fall under Specific Learning Disorder with impairment in written expression, rather than dysgraphia being a separate diagnosis.
Diagnostic criteria
As with dyslexia and dyscalculia, the difficulties must be persistent, substantially below what would be expected for the person's age and significantly affect education, work or everyday activities.
They must also have their origins during the developmental period and not be better explained by another condition or environmental factor.
Dyspraxia / Developmental Coordination Disorder
Dyspraxia, more formally known as Developmental Coordination Disorder (DCD), affects movement and coordination. It can affect gross and fine motor skills, balance, handwriting, sports, everyday tasks and, for some people, planning and organisation.
The impact varies considerably between individuals.
Diagnostic criteria
For a diagnosis of DCD, the person's motor skills must be substantially below what would be expected for their age and opportunities to learn those skills.
The difficulties must:
Significantly and persistently affect everyday activities, education, work or other areas of life;
Have begun during the developmental period; and
Not be better explained by another neurological or medical condition, visual impairment or intellectual disability.
Assessment normally includes a standardised assessment of motor skills alongside consideration of developmental history and the impact on everyday life.
Tourette syndrome
Tourette syndrome is a neurological condition characterised by both motor tics and vocal tics.
Tics are involuntary or semi-voluntary movements or sounds. They can change over time and may become more or less noticeable depending on factors such as stress and tiredness.
Diagnostic criteria
A diagnosis of Tourette syndrome generally requires:
Multiple motor tics;
At least one vocal tic;
Tics that have been present for at least one year, although they may change in type, frequency or severity;
Onset before the age of 18; and
The symptoms not being better explained by another medical condition or substance.
Tourette syndrome commonly occurs alongside other neurodevelopmental conditions, including ADHD.
Developmental Language Disorder
Developmental Language Disorder (DLD) affects the acquisition and use of spoken language. It can affect understanding language, expressing ideas, vocabulary, grammar, finding words and following complex verbal information.
The difficulties can have a significant impact on education, employment and social interaction.
Diagnostic criteria
DLD involves persistent difficulties with language development that significantly affect everyday functioning and are not better explained by another known biomedical condition or developmental disorder.
Assessment is generally carried out by speech and language professionals, often alongside information from education and other professionals.
Neurodivergence is different for everyone
A diagnosis can provide a useful framework for understanding a person's experiences, but it doesn't tell the whole story.
Two people with the same diagnosis can have very different strengths, difficulties and support needs. Someone can also have more than one neurodevelopmental condition.
For example, a person might be autistic and have ADHD, or have both dyslexia and dyspraxia. This can create a combination of characteristics that doesn't fit neatly into a single description.
That's one reason why I think it is important to talk about the individual rather than just the diagnosis.
A cautionary note about diagnosis
The criteria above are simplified summaries intended to explain the broad principles behind diagnosis. They are not diagnostic checklists.
Formal diagnosis requires assessment by appropriately qualified professionals, who consider developmental history, symptoms, their impact on everyday life and alternative explanations. Diagnostic systems and terminology can also vary between countries and may change over time.
For me, understanding neurodivergence isn't simply about learning a list of symptoms or diagnostic criteria. It's about understanding that people can experience the world in fundamentally different ways – and creating a society in which those differences don't automatically become barriers. That is why my dyspraxia blog – based, primarily, on my lived experience, is so important to me.