Understanding the Connection Between ADHD, Hypermobility and Connective Tissue
Many of us can remember at school there were always those children who could do the splits without warming up, bend their fingers back to touch their wrist or twist their bodies into seemingly effortless shapes. At the time this was often treated as a party trick or just “being bendy”, but for some people these characteristics reflect something deeper: hypermobility and differences in connective tissue that can have wider implications for health.
In recent years research has highlighted that hypermobility and related conditions, such as hypermobile Ehlers-Danlos syndrome (hEDS) and hypermobility spectrum disorders (HSD), are more common in people with neurodevelopmental differences like ADHD and autism than previously recognised (Eccles et al., 2022; Csecs et al., 2022). Understanding these connections can help people make sense of chronic symptoms they have carried for years, and support clinicians in taking a more holistic view of health.
What Is Hypermobility and Connective Tissue Variation?
Hypermobility refers to joints that move beyond the expected range for a person’s age, sex and body type (NHS, 2024). Some people have generalized joint hypermobility without other symptoms, but in others it is part of a broader connective tissue variation that may affect ligaments, tendons, skin and internal organs (Eccles, 2022).
When these features are associated with pain, instability or multisystem involvement, clinicians may consider diagnoses such as hypermobile Ehlers-Danlos syndrome (hEDS) or hypermobility spectrum disorders (HSD) (The Ehlers-Danlos Society, 2023). These differences result from variant connective tissue, which affects not just how joints move but how the whole body functions (Eccles, 2022).
How Hypermobility Links to ADHD and Neurodivergence
Research led by Dr Jessica Eccles and colleagues at Brighton and Sussex Medical School has added important evidence that hypermobility is more common in adults with neurodevelopmental conditions such as ADHD and autism than in comparison groups (Eccles et al., 2022; Csecs et al., 2022). In one study, more than half of neurodivergent participants showed elevated joint hypermobility compared with around 20 per cent in the general population (Csecs et al., 2022).
More recent peer-reviewed work has shown that joint hypermobility mediates the relationship between neurodivergence and symptoms of dysautonomia (autonomic nervous system differences) and pain (Csecs et al., 2022). In practical terms, this means that the presence of hypermobile joints is linked not just to flexibility, but to dizziness on standing, fatigue, pain and other physical symptoms that often occur alongside ADHD traits.
One way to understand this is through the lens of the brain–body connection. Dr Eccles frames hypermobility, dysautonomia and some physical symptoms as part of an integrated system in which connective tissue, internal body signalling and nervous system regulation overlap (Eccles, 2022).
Autonomic Nervous System and Dysautonomia
One of the most commonly reported physical differences in people with hypermobility is autonomic nervous system dysfunction, sometimes referred to as dysautonomia (The Ehlers-Danlos Society, 2023). The autonomic nervous system controls heart rate, blood pressure, temperature regulation, digestion and other “automatic” functions of the body.
A well-recognised example of this is postural orthostatic tachycardia syndrome (POTS), where the heart rate increases excessively on standing and can be accompanied by dizziness, brain fog, fatigue and other disabling symptoms (The Ehlers-Danlos Society, 2023). POTS and similar autonomic patterns occur more often in people with hEDS/HSD and may contribute to overlapping symptoms seen in ADHD such as inattention and fatigue (Csecs et al., 2022).
Immune System and Mast Cells: What the Evidence Says
There is increasing clinical interest in the way immune and inflammatory pathways overlap with these other systems (Weinstock et al., 2021; Afrin et al., 2020). One area of research looks at mast cells, a type of immune cell involved in allergic and inflammatory responses. When mast cells are over-reactive, this can lead to mast cell activation syndrome (MCAS), a condition associated with a range of multisystem symptoms including gut issues, headaches, flushing, fatigue and others (Afrin et al., 2020).
There is evidence that MCAS, hypermobility and dysautonomia often occur together in the same individuals, although the exact mechanisms and prevalence are still being studied (Weinstock et al., 2021). In connective tissue disorders like hEDS/HSD, immune signalling and autonomic differences appear to overlap more often than would be expected by chance (The Ehlers-Danlos Society, 2023).
Importantly this does not mean that everyone with ADHD has MCAS, or that immune dysfunction causes ADHD. It means there is a pattern of overlap in some people, particularly in those whose connective tissue variation affects multiple body systems.
Why This Matters for Lived Experience
Many people with ADHD describe physical symptoms that have been present their whole lives but were never fully understood. Joint pain, injury proneness, dizziness on standing, chronic fatigue, gut sensitivities, headaches and sensory differences can all feel unrelated to each other — until you realise they may be part of a connected neuro-immune-connective tissue pattern (Eccles et al., 2022; Csecs et al., 2022).
Recognising these links does not replace individual clinical assessment, but it can:
• help people make sense of long-standing symptoms
• guide clinicians to consider multisystem assessments
• reduce frustration from “unexplained” health experiences
• support referral to appropriate therapies such as physiotherapy for stability, autonomic regulation support, pain management, and when relevant, allergy or immune consultation
A Shared Narrative, Not a Single Cause
It is crucial to be clear that:
• hypermobility does not cause ADHD
• immune or mast cell issues do not explain all ADHD traits
• not everyone with ADHD has dysautonomia, MCAS or connective tissue variation
What the research suggests is that, for some people, these systems interact in ways that contribute to the overall lived experience of symptoms that can accompany ADHD (Csecs et al., 2022; Eccles et al., 2022).
Dr Eccles’ ongoing work, including clinical and neuroscience studies exploring connectivity and chronic symptom mechanisms, continues to deepen our understanding of these links (Eccles, 2022).
References
Afrin, L.B., Self, S., Menk, J. and Lazarchick, J. (2020) Characterization of mast cell activation syndrome. American Journal of the Medical Sciences, 359(5), pp. 249–261.
Csecs, J.L.L., Iodice, V., Rae, C.L., et al. (2022) Joint hypermobility links neurodivergence to dysautonomia and pain. Frontiers in Psychiatry, 12, 786916. https://doi.org/10.3389/fpsyt.2021.786916
Eccles, J.A., Owens, A.P., Mathias, C.J., Umeda, S., Critchley, H.D. (2022) Variant connective tissue (joint hypermobility) and its developmental effects on body, brain, and behaviour. BMJ Open, 12, e066130. https://doi.org/10.1136/bmjopen-2022-066130
NHS (2024) Joint hypermobility syndrome. Available at: https://www.nhs.uk (Accessed 2026).
The Ehlers-Danlos Society (2023) Autonomic dysfunction in hypermobile Ehlers-Danlos syndrome and HSD. Available at: https://www.ehlers-danlos.com (Accessed 2026).
Weinstock, L.B., Brook, J.B., Myers, T.L. and Goodman, B. (2021) Mast cell activation syndrome: A review. Current Allergy and Asthma Reports, 21(6), 31.
Pain Concern Podcast (2023) Discussion of hypermobility and neurodiversity research with Dr Jessica Eccles.
ADDitude Magazine (2024) Joint hypermobility and neurodivergence.