There is a lot of current interest surrounding neurodivergence in Scotland, especially given the long waiting lists for neurodevelopmental assessments and the withdrawal of services in some areas. But what are we talking about when we talk about neurodiversity, neurodivergence and neurodevelopmental conditions? This SPICe blog explains the key terminology in this area.
What is neurodiversity?
The word ‘neurodiversity’ describes the natural variation in brain function and development. ‘Diversity’ is a feature of a group, rather than an individual; a group or population can be ‘neurodiverse’, but a single person cannot.
Since first being used as a term in the late 1990s, the word ‘neurodiversity’ has come to represent an entire framework for understanding human brain function. Under this framework, there is no one ‘right’ way for a brain to work. People process, think about and understand the world in different ways, and differences from the ‘normal’ or ‘conventional’ should be embraced as such, rather than classified as disorders or deficits.
Neurodivergent and neurotypical
The brain is responsible for almost every function of the human body in some way. However, the specific brain functions that neurodiversity relates to are called ‘neurocognitive functions’. Some examples of these are:
- the ability to learn and use language
- the ability to regulate attention, emotions, impulses (including movements and spontaneous utterances)
- social behaviours
- processing sensory stimuli.
For each of these functions, there is a statistically normal range that changes with age. Where a person falls within this range is generally considered a product of both their genetics and their environment – it is both ‘nature’ and ‘nurture’, although the factors at play are poorly understood.
Someone whose neurocognitive functions fall within the normal range is described as ‘neurotypical’. If some (but not necessarily all) of a person’s neurocognitive functions fall outside the normal range, that person is described as ‘neurodivergent’.
Neurodevelopmental Conditions
Current estimates suggest that roughly 10-20% of people are neurodivergent. Specific forms of neurodivergence that cause significant functional impairment are classified as neurodevelopmental conditions. Examples include:
- Autism
- Attention Deficit-Hyperactivity Disorder (ADHD)
- Developmental Co-ordination Disorder (DCD, formerly known as dyspraxia)
- Developmental Language Disorder (DLD)
- Dyslexia and dyscalculia
- Foetal Alcohol Spectrum Disorder (FASD)
- Tourette’s syndrome.
Of these, dyslexia is the most common, affecting around 10% of the population. ADHD, DCD, DLD, dyscalculia and FASD each have prevalences of roughly 4-7%, while autism (3%) and Tourette’s syndrome (1%) are slightly less common. Most of these conditions are diagnosed more frequently in men than in women, although evidence suggests that at least some of this discrepancy is due to under-diagnosis in women and girls. These conditions are generally lifelong, although medication, therapies and environmental adaptations may improve outcomes for some neurodivergent people.
Neurodevelopmental conditions commonly co-occur with each other. Studies have estimated that as many as 70% of autistic people also have ADHD, and similar patterns are observed for other neurodevelopmental conditions. As a result, guidance from NHS Education for Scotland describes taking a ‘neurodevelopmental approach’ to the assessment and treatment of these conditions, where a person’s entire neurodevelopmental profile – rather than specific conditions – is considered.
Neurodevelopmental conditions may impact people’s lives in a range of ways. For example, some autistic people are able to live fully independent lives, while others can require round-the-clock support. Neurodivergence is not a mental health condition, but neurodivergent people are more likely to experience mental and physical health difficulties in their lives, in part due to the stigma and discrimination they experience. Because of these adverse effects, evidence suggests that autistic people and people with ADHD live on average for six to eight years less than their neurotypical peers. This is shown in the figure below.
Summary
Neurodiversity is a term used to describe the variation of brain function across a group of people. Individuals whose neurocognitive functions lie within the usual range as described as neurotypical, while those whose functions fall outside that range are labelled neurodivergent. Specific neurodevelopmental conditions include autism and ADHD and frequently co-occur with each other. Some people with these conditions lead fully independent lives, while others require varying degrees of support in different aspects of their lives. Regardless, neurodivergence is a result of differences in brain function, rather than deficit, and many feel that neurodiversity is something that should be affirmed and celebrated, rather than treated or cured.
Ben Adam, Researcher, SPICe
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