This piece is written for colleagues rather than clients. It sets out the clinical distinction we use between neurodiversity and neurodivergent at Storm’s Edge Therapy, and places it against a genuinely contested history within the neurodiversity movement itself, one that has generated a formal correction in the academic literature as recently as 2024. Anyone borrowing our terminology should understand where it agrees with the movement’s own usage, where it departs, and why the departure is a considered choice rather than an oversight.

The Clinical Distinction, Restated

Neurodivergent, in our usage, denotes a diagnosable or diagnosed condition sitting within recognised psychiatric or neuropsychological classification: autism spectrum condition, ADHD or ADD, dyslexia, dyspraxia, and comparable conditions. Neurodiversity denotes a broader, non-diagnostic category describing the range of human cognitive profiles, including giftedness, which need not meet any diagnostic threshold at all. The two overlap in twice-exceptional presentations but aren’t synonyms.

This is a proposal for internal and client-facing use, not a claim that the wider field has settled on this usage. It hasn’t. The field’s own foundational terms remain under active dispute among the scholars who built them.

Origins: a More Contested History Than Thought

Most clinical training that touches on neurodiversity attributes the term to Judy Singer, an Australian sociologist whose 1998 honours thesis at the University of Technology Sydney documented an emerging disability and social movement among autistic people and their allies, drawing on her observation of the online community Independent Living on the Autistic Spectrum (InLv). Singer’s thesis was later condensed into a 1999 book chapter, and this has long served as the standard origin story.

That attribution has been formally challenged. A 2024 letter in the journal Autism, authored by six autistic scholars of autism and neurodiversity (Monique Botha, Robert Chapman, Morénike Giwa Onaiwu, Steven Kapp, Abs Stannard Ashley and Nick Walker), presents archival evidence that the terms “neurological diversity” and “neurodiversity” appeared in print earlier than Singer’s thesis, in journalist Harvey Blume’s 1997 and 1998 writing, and that Blume himself attributed the underlying idea not to Singer but to the online autistic community, citing groups such as the Institute for the Study of the Neurologically Typical. The letter also cites researcher Martijn Dekker’s discovery of a 1996 InLv post by Tony Langdon describing “the neurological diversity of people” and its role in generating new perspectives, predating Singer’s thesis by two years. The authors’ conclusion is that neurodiversity as a concept and a body of theory was developed collectively by autistic people online through the 1990s, rather than originating with any single author, and that continued single-author attribution misrepresents the historical record.

Worth noting for context, since it shapes how live this dispute currently is: the archival reassessment gained public attention alongside separate, unrelated controversy concerning comments attributed to Singer on social media that a number of autistic advocates characterised as transphobic, which Singer has disputed. The academic argument in the Autism letter stands independently of that controversy and rests on documentary evidence rather than on it, but the two developments surfaced close together and are often discussed together in the wider community, so it’s worth being aware of both threads rather than treating the terminology dispute as a purely academic footnote.

Separately, the adjective “neurodivergent” and the noun “neurodivergence” are credited to autistic activist Kassiane Lucas, writing at the time under the name Kassiane Asasumasu, who coined both terms around 2000 as deliberately broader than autism, covering any neurocognitive style diverging from dominant standards of “normal.” This attribution is less contested than Singer’s, though the 2024 letter situates even this within a wider collective development rather than crediting it as an isolated act of coinage.

Walker’s Formalisation, and Our Departure

Psychologist Nick Walker, one of the co-authors of the 2024 correction, published the most widely cited formal definitions of this vocabulary, developed from 2003 onward and collected in the 2021 book Neuroqueer Heresies. Walker’s definitions, still the closest thing the field has to a standard reference, hold that:

• Neurodivergent is an adjective describing an individual whose neurocognitive functioning diverges significantly from dominant societal standards of “normal.” It is not limited to any specific condition and is explicitly not a synonym for autistic.
• Neurodiversity is a property of a group, not of an individual, analogous to biodiversity. On this account, an individual can diverge; only a population can be diverse. “Neurodiverse” cannot correctly be used as a synonym for “non-neurotypical,” since neurotypical people are themselves part of the neurodiversity of any group they belong to.
• The neurodiversity paradigm and the Neurodiversity Movement are further distinct terms: the paradigm is a way of understanding neurocognitive variation as natural rather than pathological, while the movement is the social and political activism built on that paradigm.

Walker’s formulation does not require a formal diagnosis for “neurodivergent” to apply. Divergence from dominant norms is the criterion, not the presence of a diagnostic code, and Walker explicitly includes conditions like traumatic brain injury as legitimately medical forms of neurodivergence while resisting a pathology framing for others, such as autism.

Our usage departs from Walker’s in two specific respects, and we think both departures are worth stating plainly to colleagues rather than leaving implicit:

First, we use “neurodiversity” to describe an individual’s cognitive profile, not only a property of groups. Walker’s account would treat this as a category error. We adopt it anyway because, for clinical purposes, we need a non-diagnostic term that can be applied to a single client’s presentation, and no equally established alternative exists. A client with a markedly unusual cognitive profile and no diagnosis needs language for that profile in the room with us, not only language for the population they happen to belong to.

Second, we restrict “neurodivergent” to diagnosable or diagnosed conditions, narrower than Walker’s criterion of significant divergence from dominant norms regardless of diagnostic status. This is a deliberate narrowing for clinical utility: in assessment, referral and reporting contexts, the distinction between a diagnosable presentation and a self-recognised but non-clinical difference in thinking carries real consequences, for access to accommodations, for how a formulation is written, and for what a client can reasonably expect from statutory services.

Neither departure is a claim that Walker’s account is wrong for its own purposes. Walker’s definitions were built for a social and political movement seeking recognition and rights for neurominorities as a class. Ours are built for individual clinical formulation. The two projects have different requirements, and importing movement terminology unmodified into a clinical setting creates exactly the kind of definitional gap this piece and its companion blog post are trying to close.

Where Giftedness Sits and Asynchronous Development

A further complication worth flagging for colleagues: some writers in this space argue that giftedness itself constitutes a form of neurodivergence, most often on the grounds of asynchronous development, a concept originating with the Columbus Group’s 1991 definition of giftedness as advanced cognitive ability and heightened intensity combining to produce inner experience qualitatively different from the norm, with asynchrony increasing at higher intellectual capacity. Kazimierz Dabrowski’s earlier work on overexcitability, describing heightened, prolonged reactivity across psychomotor, sensual, imaginational, intellectual and emotional domains, is frequently cited alongside asynchronous development as further evidence that gifted cognition diverges structurally, not just quantitatively, from typical patterns.

Under Walker’s criterion of significant divergence from dominant norms, this argument has real force. Under our narrower clinical definition, asynchronous development and overexcitability describe cognitive and developmental profile, not diagnosis, and so sit within neurodiversity rather than neurodivergence unless a client also holds a diagnosable co-occurring condition, in which case twice-exceptional presentation applies. We think this is the more clinically useful placement, but colleagues should recognise it as a placement decision, not an uncontested fact, and should expect gifted clients who have engaged with the wider neurodiversity literature to sometimes push back on it.

Practical Implications for Documentation and Practice

A few working principles follow from this for how we write and speak about client presentations:

• In formulations, reports and referral letters, “neurodivergent” should only be used where a diagnosis is present, established, or actively being pursued through formal assessment. Where a client presents with an unusual cognitive profile and no diagnosis, “neurodiverse” or “neurodiverse thinking style” is the more accurate term, and avoids implying a diagnostic status that hasn’t been established.
• Where a client self-identifies as neurodivergent without formal diagnosis, that self-identification should be recorded and respected as their own language, while our own clinical language in formulation can maintain the distinction for accuracy. The two aren’t in conflict: a client’s identity language and a clinician’s diagnostic precision serve different purposes.
• For twice-exceptional presentations, name both elements explicitly (for example, “gifted and autistic,” or “twice-exceptional, autism spectrum condition”) rather than defaulting to only one label, given how frequently each masks the other in adult presentations.
• When writing for a client-facing or public audience, as in the companion blog post, hold the terminology distinction but frame it as our practice’s working proposal rather than settled fact, consistent with how genuinely unsettled this vocabulary is even within its originating movement.

A Note on Revising This Terminology

Given how recently the origins dispute was formalised in the literature (2024), and given that Walker himself remains an active, publishing voice whose definitions continue to evolve, this piece should be treated as a snapshot rather than a fixed reference. And is therefore worth revisiting if further correction, consensus or terminology shift emerges from the field.

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