Diagnostic Drift, Hypermobility, and the Conceptual Boundaries of hEDS

Although this article is aimed primarily at clinicians, researchers, and other healthcare professionals, readers with a personal interest in hEDS may also find it valuable. While some sections are necessarily more technical, I hope the broader discussion remains accessible to a wider audience.

One issue that is rarely discussed in depth within the literature on hypermobile Ehlers-Danlos syndrome (hEDS) is the question of diagnostic drift. Diagnostic drift refers to the gradual expansion or loosening of diagnostic boundaries in clinical practice, whereby a condition begins to include a broader and more heterogeneous group of patients than those originally defined by formal diagnostic criteria. In the context of hEDS, this is not a minor technical issue. It has important implications for how the condition is conceptualized in both clinical practice and academic discourse, particularly in relation to neuroplastic models of symptom generation, which have become increasingly influential in this area. I have previously written two articles exploring hEDS, its diagnostic classification, and the potential clinical and conceptual consequences of such interpretative shifts that you can find here and here.

The specificity of the hEDS diagnostic criteria

The 2017 diagnostic criteria for hEDS are intentionally specific. They require not only generalized joint hypermobility, but also additional systemic features of connective tissue involvement and the exclusion of alternative diagnoses (for readers unfamiliar with the current diagnostic criteria, they can be found here). These criteria were designed to distinguish hEDS from other forms of hypermobility and from unrelated chronic symptom presentations. However, in real-world clinical practice, particularly in primary care or in settings where specialist assessment is limited, application of these criteria is not always consistent. Individuals presenting with generalized joint hypermobility alongside chronic pain, fatigue, dizziness, anxiety, autonomic symptoms, or mast cell-type symptoms may sometimes receive an hEDS diagnosis without full structured assessment against the formal criteria. In some instances, this may reflect a more limited application of the Beighton score as a proxy for diagnosis, rather than a comprehensive evaluation of the full 2017 criteria. In my clinical experience, I have encountered individuals who were given an hEDS diagnosis by general practitioners or even rheumatologists based primarily on hypermobility testing, without systematic assessment of the additional required systemic features.

This is relevant because some descriptions of hEDS within neuroplastic frameworks appear to place a strong emphasis on hypermobility without always engaging with the full multisystem nature of the 2017 diagnostic construct. This raises concerns about potential conceptual simplification of the condition in some contexts, particularly when it is discussed primarily through the lens of symptom generation rather than diagnostic criteria. In such cases, individuals may more accurately meet criteria for hypermobility spectrum disorder (HSD), or may present with benign hypermobility alongside overlapping neuroplastic or functional symptom processes. This reflects not clinical error per se, but the complexity of symptom presentations and the practical limitations of clinical settings. Nevertheless, it creates diagnostic heterogeneity that is often not explicitly acknowledged.

From diagnostic category to descriptive label

When diagnostic boundaries become less precise, the label “hEDS” can gradually shift in meaning. Instead of functioning as a narrowly defined connective tissue disorder, it may begin to operate as a broader descriptive category for complex multisystem symptom presentations associated with hypermobility. Over time, this can lead to symptom clusters such as pain, dizziness, fatigue, anxiety, and sensory sensitivity being interpreted as defining features of hEDS itself, rather than as non-specific symptoms that may arise from multiple underlying mechanisms. This creates a conceptual overlap between distinct physiological and neuroplastic processes. Connective tissue pathology, autonomic dysfunction, mast cell-type symptoms, and neuroplastic or functional symptom mechanisms may become grouped together under a single diagnostic umbrella, despite being biologically and clinically distinct.

Implications for neuroplastic models

This issue becomes particularly relevant when considering neuroplastic explanations of chronic symptoms, including those discussed in my recent critique of Dr. Howard Schubiner’s framing of hEDS as a neuroplastic condition. If a heterogeneous population is collectively labelled as having hEDS, including individuals whose primary mechanisms are neuroplastic, functional, or autonomic rather than structural connective tissue pathology, then it may appear that hEDS itself is largely a neuroplastic condition. However, this conclusion may reflect diagnostic heterogeneity rather than true disease classification. What appears to be a single condition characterized by neuroplastic symptoms may in fact represent a mixed population that includes individuals with true hEDS as a systemic connective tissue disorder, individuals with hypermobility spectrum disorder without systemic connective tissue involvement, and individuals whose symptom burden is primarily driven by neuroplastic or functional processes alongside hypermobility. These groups may overlap clinically, but they are not identical in underlying pathology or diagnostic meaning.

Clinical consequences of blurred boundaries

This distinction matters because diagnostic framing directly influences clinical reasoning. When diagnostic categories become blurred, there is a risk that structural complications associated with hEDS may be under-recognized, while neuroplastic explanations are applied too broadly within clinical interpretation. At the same time, it is equally important not to overcorrect in the opposite direction by attributing all symptoms in hEDS to structural pathology alone. Multiple mechanisms may coexist within the same individual, but this does not justify collapsing them into a single explanatory framework. Clinical reasoning depends on maintaining distinctions between mechanisms even when they interact.

Why conceptual clarity is essential

Ultimately, diagnostic clarity is not a purely academic concern. It has direct implications for how conditions are understood, studied, and treated. In the case of hEDS, maintaining clear boundaries between hypermobility without systemic disease, hypermobility spectrum disorder, and true hEDS as a connective tissue disorder is essential for accurate clinical reasoning. Without this clarity, heterogeneous symptom populations risk being conceptually unified under a single label, which can lead to oversimplified conclusions about the nature of the condition and its relationship to neuroplastic mechanisms. This issue is particularly relevant to the broader debate explored across my recent essay series examining neuroplastic interpretations of hEDS and their implications for clinical practice. Across these essays, a central concern has been how conceptual frameworks, when applied too broadly, can inadvertently obscure important biological, structural, and diagnostic distinctions within complex conditions. Maintaining these distinctions is essential if we are to preserve both scientific accuracy and clinical usefulness in how hEDS is understood.

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Dr. Ingela Thuné-Boyle is a licensed Practitioner Health Psychologist and a Doctor in Behavioural Medicine who specializes in improving the quality of life of people struggling with long-term health problems, chronic pain and trauma. She runs a private online (telehealth) practice at www.ingelathuneboyle.com. You can find out more about her background [here], and more about her approach to therapy [here].

📩 Contact: For therapy or other enquiries, you can contact her at info@ingelathuneboyle.com.

Please note: Advice given in this blog is not meant to take the place of therapy or any other professional advice. The opinions and views offered by the author is not intended to treat or diagnose, nor is it intended to replace the treatment and care that you may be receiving from a licensed physician or mental health provider. The author is not responsible for the outcome or results following their information and advice on this blog.