How can a connective tissue disorder impact the brain?
Ehlers-Danlos syndromes (EDS) are a group of heritable connective tissue disorders, best known for joint hypermobility, stretchy skin and tissue fragility. Hypermobility spectrum disorders (HSD) are a group of conditions involving symptomatic joint hypermobility that don’t meet the diagnostic criteria for hypermobile Ehlers-Danlos syndrome (hEDS) or another heritable connective tissue disorder. But connective tissue isn't just in your joints and skin. It's in your blood vessels, your gut, and what most people don’t know realise - it’s also the protective layers around your brain. So it shouldn't be surprising that EDS reaches how our brain functions day to day.
Neurodivergent people are up to five times more likely to have a connective tissue disorder
A brand new landmark study published in August 2026 studied more than 117 million people (15+) and grouped them into three categories: autism only, ADHD only, and both autism and ADHD, often called AuDHD, and compared each with matched people without a neurodevelopmental diagnosis, of the same age and sex and with similar healthcare use (1). From here, they reported the rates of occurrence of connective tissue disorders compared to neurotypical controls.
Compared to those without a neurodevelopmental diagnosis:
Autism and ADHD co-occurring AuDHD
These participants had:
→ 438% higher likelihood of a heritable structural connective tissue disorder (such as Ehlers-Danlos Syndrome and Marfan Syndrome)
→ 340% higher likelihood of a hypermobility spectrum disorder
Autism-only
→ 311% higher likelihood of heritable structural connective tissue l disorders
→ 203% higher likelihood of hypermobility spectrum disorders
ADHD-only
→ 170% higher likelihood of heritable structural connective tissue disorders
→ 148% higher likelihood of hypermobility spectrum disorders
Neurodivergence and hypermobility have been turning up together for years
A Swedish study published back in 2016 also noticed this link, and found that people with Ehlers-Danlos Syndrome are 7.4x more likely to be autistic and 5.6x more likely to have ADHD (2). Interestingly, in this study, sibling comparisons showed that ADHD was still more likely to be diagnosed in siblings without EDS, showing that it could be a genetic overlap or early life factors contributing rather than EDS itself.
How can a connective tissue disorder impact the brain?
Shared Roots: The Connectiveome Theory
Connective tissue is all over your body, and fills the brain through a couple different ways.
Firstly, your brain is wrapped in three protective l layers, called the meninges, which are made of different types of connective tissue. These layers physically protect the brain, and provide blood flow and lymphatic drainage where needed.
Secondly, connective tissue makes up the structural base of the blood-brain-barrier, a protective layer that separates molecules in your bloodstream from the delicate brain and spinal cord. If there are defects in this system, systemic inflammation can become neuroinflammation, which is increasingly linked to neurodivergence (3).
Differences in connective tissue can shape how the brain envelope and functions since before birth, and day to day throughout your life, so this could be an underlying reason for the link to the increased likelihood of neurodivergence
A Hypermobile Body May Amplify the Neurodivergent Brain
The Proproception Overload
Proprioception is your sense of where your body is in space. It relies on sensors in your joints, ligaments and muscles. When connective tissue is lax, those signals become less precise.
Your brain constantly predicts where your body is in space. When it gets it wrong, it sends a "surprise" signal. With hypermobility, movement patterns are less predictable, so the brain receives constant error signals. This may heighten sensory sensitivity and push the nervous system towards overload, amplifying neurodivergent traits.
A 2024 study aimed to test this. Here, they recruited 182 adults and tested how joint hypermobility and proprioceptive error signals link neurodivergence to emotional regulation (4). Of all participants, 50% were hypermobile and 45% were neurodivergent. Joint hypermobility did not have a significant direct link to emotional dysregulation, it was entirely mediated by this proprioceptive "surprise" signal. Neurodivergence is directly associated with emotional regulation, but this is amplified two fold when hypermobility is present. What this means: Being neurodivergent can make processing bodily signals more complex, but having hypermobile joints acts like turning up the volume on those confusion signals, amplifying the neurodivergent experience.
The Blood Flow Theory
Dysautonomia means your autonomic nervous system, which controls heart rate and blood pressure automatically, isn't regulating properly. A common form is postural orthostatic tachycardia syndrome (POTS), where your heart rate spikes on standing and you may feel dizzy, foggy or faint.
POTS, or regularly feeling dizzy, or syncope (fainting), is common in hEDS. One explanation is that more elastic blood vessels let blood pool in the lower body when you stand, so less returns to the heart, and the body overcompensates.
So how might this affect your brain functioning? Brain fog is one of the most common POTS symptoms, but the mechanism is more complex than simply less blood reaching the brain. During graded tilting, average blood flow to the brain stayed similar in people with POTS, but it fluctuated much more, and these fluctuations were linked to poorer cognitive performance (5). A small study also found poorer short-term memory and attention switching in POTS, even while seated and with normal blood flow measures (6).
For neurodivergent people who are also hypermobile or have connective tissue disorders, these effects may stack on top of existing differences in attention and executive function, amplifying the neurodivergent experience.
Takeaway
Though the science is still emerging, this latest study shows a real overlap between neurodivergence and connective tissue disorders, urging clinicians to screen for both conditions simultaneously. It also encourages future research into this co-occurrence.
References
1. Bartelt, K., Keane, G., Franklin, B., & Higgs, E. (2026, August 20). Neurodivergence linked to higher rates of connective tissue disorders. Epic Research. Epicresearch.Org. https://www.epicresearch.org/articles/neurodivergence-linked-to-higher-rates-of-connective-tissue-disorders/
2. Cederlöf M, Larsson H, Lichtenstein P, Almqvist C, Serlachius E, Ludvigsson JF. Nationwide population-based cohort study of psychiatric disorders in individuals with Ehlers-Danlos syndrome or hypermobility syndrome and their siblings. BMC Psychiatry. 2016 Jul 4;16:207. doi: 10.1186/s12888-016-0922-6. PMID: 27377649; PMCID: PMC4932739.
3. Schnorr I, Siegl A, Luckhardt S, Wenz S, Friedrichsen H, El Jomaa H, Steinmann A, Kilencz T, Arteaga-Henríquez G, Ramos-Sayalero C, Ibanez-Jimenez P, Rosales-Ortiz SK, Bitter I, Fadeuilhe C, Ferrer M, Lavebratt C, Réthelyi JM, Richarte V, Rommelse N, Ramos-Quiroga JA, Arias-Vasquez A, Resch E, Reif A, Matura S, Schiweck C. Inflammatory biotype of ADHD is linked to chronic stress: a data-driven analysis of the inflammatory proteome. Transl Psychiatry. 2024 Jan 18;14(1):37. doi: 10.1038/s41398-023-02729-3. PMID: 38238292; PMCID: PMC10796401.
4. Eccles JA, Quadt L, Garfinkel SN, Critchley HD. A model linking emotional dysregulation in neurodivergent people to the proprioceptive impact of joint hypermobility. Philos Trans R Soc Lond B Biol Sci. 2024 Aug 26;379(1908):20230247. doi: 10.1098/rstb.2023.0247. Epub 2024 Jul 15. PMID: 39005028; PMCID: PMC11444222.
5. Stewart JM, Del Pozzi AT, Pandey A, Messer ZR, Terilli C, Medow MS. Oscillatory cerebral blood flow is associated with impaired neurocognition and functional hyperemia in postural tachycardia syndrome during graded tilt. Hypertension. 2015 Mar;65(3):636-43. doi: 10.1161/HYPERTENSIONAHA.114.04576. Epub 2014 Dec 15. PMID: 25510829; PMCID: PMC4326551.
6. Wells R, Paterson F, Bacchi S, Page A, Baumert M, Lau DH. Brain fog in postural tachycardia syndrome: An objective cerebral blood flow and neurocognitive analysis. J Arrhythm. 2020 Mar 3;36(3):549-552. doi: 10.1002/joa3.12325. PMID: 32528589; PMCID: PMC7280003.
