Hypermobility, Autism, and ADHD: Why the Bendy-Joints Connection Keeps Coming Up
Last reviewed: 10/09/2026
Reviewed by: Dr. Kiesa Kelly
You read a thread late one night. Someone with ADHD mentions they can bend their thumb back to their wrist, and dozens of replies say the same. A few people mention Ehlers-Danlos syndrome, dizziness when they stand up, and joints that ache for no clear reason. You look at your own fingers, think about your autistic teenager's endless sprains, and wonder whether you have just found a hidden piece of the puzzle.
The link between hypermobility, autism, and ADHD is a real research topic, not just an online theory. But what the studies show is narrower than the threads suggest, and the two halves of the question are checked by different professionals. A psychological assessment can answer the autism and ADHD half. The connective-tissue half belongs to a physician. This article sorts out which is which.
In this article, you'll learn:
What the research on hypermobility, autism and ADHD does and does not show
Why the type of study changes what the numbers mean
What hypermobility, hEDS and HSD are, and who diagnoses them
The hypotheses for why the link might exist, and how strong each one is
What this means for an autism or ADHD evaluation, and when to see your doctor
The short answer: what the research does and doesn't show
Studies of adults, two of them recruited mainly through specialist clinics, find generalized joint hypermobility more often in autistic and ADHD adults than in comparison groups [1][2][3]. A large Swedish register study found that people with a recorded diagnosis of Ehlers-Danlos syndrome (EDS) or the older diagnosis "hypermobility syndrome" were more likely to also have a recorded autism or ADHD diagnosis [4]. A 2025 review of autism studies found that most studies testing the link reported one [5].
That is the part that keeps coming up. The part that comes up less often is just as important. Two studies outside clinics found no link: a survey of non-clinical adults, most of them working in healthcare, which looked at autism and ADHD traits rather than diagnoses, and an exam-based study of 11-year-old schoolchildren [6][7]. Most of the positive studies are cross-sectional, so they cannot show which came first or why. And being flexible is common in the general population [8][9].
🧩 Key takeaway: Hypermobility shows up more often alongside autism and ADHD in clinic and register studies, but that is an association, not a cause and not a diagnostic sign.
Three misconceptions about the hypermobility link
"About half of autistic and ADHD people have Ehlers-Danlos." This figure seems to trace back to a 2022 UK study, which found that about half of its neurodivergent adults met a threshold for generalized joint hypermobility on a physical exam [1]. Most of those adults were seen in NHS secondary-care outpatient clinics, including a specialist adult neurodevelopmental service, and the researchers did not assess anyone for hypermobile EDS (hEDS) or hypermobility spectrum disorder (HSD) [1]. Hypermobility on an exam is not the same as a connective-tissue disorder. Using a stricter age-adjusted cutoff, the figure in the same study fell to 28.4 percent, against 12.5 percent in its comparison group [1].
"If you are bendy, that is a sign of autism or ADHD." Being flexible on its own is common and usually not a problem. The Ehlers-Danlos Society says hypermobility continues into adulthood for up to about 20 percent of people [8], while the NHS puts joint hypermobility at around 1 in 30 [9]. The gap between those figures likely reflects different definitions and age groups; there is no settled number. In a survey of 887 adults from a non-clinical population, self-reported hypermobility was not linked with ADHD or autism traits [6]. If you are wondering about autism or ADHD themselves, screeners such as the AQ-10 ask about the traits clinicians actually look at. A screener is a starting point, not a diagnosis.
"An autism or ADHD evaluation can tell you whether you have hEDS." It cannot. Hypermobile EDS currently has no genetic test, and it is diagnosed from medical history and a physical examination against clinical criteria [10][9]. HSD is diagnosed the same way, with other conditions that can cause the same symptoms ruled out [8]. That is medical work. A psychological evaluation can notice the symptoms and point you toward the right doctor.
🔍 Key takeaway: The famous "half" figure is generalized joint hypermobility in a clinic sample, not EDS, and flexibility alone tells you nothing about autism or ADHD.
What "hypermobility" means (and what hEDS and HSD are)
Being flexible vs. a hypermobility disorder
Joint hypermobility means joints that move further than most. For many people it causes no trouble, and hypermobility that causes no pain or other symptoms does not need treatment [8]. The Ehlers-Danlos syndromes are a group of 13 inherited connective-tissue conditions [11][10]. Hypermobile EDS is the most common type, and it is the only one diagnosed on clinical criteria rather than by finding a genetic cause [11][10].
Hypermobility spectrum disorders are diagnosed when joint hypermobility causes real problems, such as instability, injuries or pain, but does not meet the criteria for hEDS or another syndrome [12][8]. These labels date from 2017. Older terms such as "joint hypermobility syndrome" are no longer used for diagnosis [12][10], which is one reason older and newer studies are hard to compare. Our article on common medical conditions alongside autism covers what to track and when physical therapy, rheumatology or genetics may help, so we do not repeat that here.
Who diagnoses it: a physician, not a psychologist
In the UK, the NHS describes the route as starting with a family doctor, who may refer to a rheumatologist for joint problems or to a genetics service if a rarer type of EDS is possible [9]. Care systems differ, and in the US this usually starts with a primary care clinician. Either way, whether you have hEDS or HSD is decided by a physician through history and examination, not by a psychologist through questionnaires.
🩺 Key takeaway: Hypermobility is common. hEDS and HSD are medical diagnoses made by a physician, and an autism or ADHD evaluation is not designed to make them.
What studies have found about autism, ADHD and hypermobility
The ADHD side
The evidence for ADHD is, if anything, more consistent than the evidence for autism. In the 2022 UK clinic study, adults with ADHD had about 4.3 times the odds of generalized joint hypermobility compared with an adolescent population cohort [1]. A Swedish case-control study of 431 adults with ADHD found an adjusted odds ratio of 4.7 for hypermobility on exam, rising to 6.9 when hypermobility came with joint or skin symptoms [2]. In the national register study, people with hypermobility syndrome were 5.8 times as likely to have an ADHD diagnosis, though the absolute rates were low: 3.0 percent against 0.5 percent [4]. A 2025 research team summarizing the field described ADHD as having the most robust link with joint hypermobility in studies of children, and robust associations in adults [7].
If ADHD is the question for you, the ASRS adult screener asks about the core symptoms clinicians assess.
The autism side
A 2025 review included 20 studies, 12 of them on hypermobility in autistic people, and pooled the results from autistic samples. Joint hypermobility showed up in about 22 percent overall, and 31 percent when it was examined in person rather than self-reported. HSD or EDS showed up in about 28 percent overall, and 39 percent when assessed clinically [5]. Those are rates within the studies' samples, not estimates for autistic people in general, and the authors called for confirmation [5].
A large Swedish adult study adds an important twist. In 199 autistic adults from specialist clinics, autism was linked with hypermobility on exam (adjusted odds ratio 3.1). But 69 percent of those adults also had ADHD, and among the autistic adults without ADHD the link was not statistically significant [3]. The authors suggested ADHD may be the main driver of the autism-hypermobility association [3]. That subgroup was small, so it does not rule out a link with autism alone. But it is a good reason to think about autism and ADHD together, and our article on AuDHD versus autism or ADHD alone explains why the combination matters.
Clinic samples vs. population cohorts
How a study finds its participants changes what its numbers mean. Clinic studies recruit people who are already seeking help, and the authors of one noted that recruiting from a different source might have given a different result [3]. The UK clinic study compared its participants with a "general population" figure of about 20 percent that came from a separate study of adolescents, not from adults measured alongside them [1]. The register study is large and population-based, but it only counts diagnoses recorded in hospitals, so it says nothing about milder hypermobility that never reached a hospital diagnosis [4].
Two studies that looked outside clinics did not find the link. Among 887 adults from a non-clinical population, self-reported hypermobility was not associated with ADHD or autism traits, and the authors concluded the association "is presumably limited to clinical populations" [6]. Among 207 Swedish 11-year-olds examined at school, high hypermobility scores were not linked with neurodevelopmental problems [7]. Both have limits: the adult study used self-report, and the child study was small. Still, they are a useful check on the clinic numbers.
The distinguishing pattern: the clinic and register numbers describe people who are already in the health system. They tell you a link is worth taking seriously, not how likely it is that a flexible person is autistic or has ADHD, or the reverse.
📊 Key takeaway: Ask where a study's participants came from. Clinic and register studies find a link, while the two community studies described here did not, and much of the autism link may run through co-occurring ADHD.
Why the connection might exist (hypotheses, stated as hypotheses)
None of these explanations is established. Each is a researcher's proposal based on the data they had.
Shared family factors. In the register study, siblings of people with EDS or hypermobility syndrome also had somewhat higher rates of some psychiatric diagnoses, including ADHD. The authors suggested shared genetic or early environmental factors may play a role [4].
A marker of something broader. The authors of the adult ADHD study suggested hypermobility "may represent a marker" of an underlying process affecting both connective tissue and the nervous system [2].
Body-position signals. One research group has proposed that hypermobile joints may give the brain less precise signals about where the body is, and that this may link neurodivergence with emotional dysregulation. That model came from an online survey using questionnaires, not diagnoses or physical exams, and its authors say it needs testing [13].
Blood flow and tissue sensitivity. The UK clinic team proposed that differences in connective tissue might allow blood to pool in looser blood vessels and make tissues more sensitive, which could help explain dizziness and pain [1].
Who gets looked at. People already being seen for one condition may be more likely to be checked for others. The register authors could not rule out this kind of surveillance bias, although the raised rates in unaffected siblings argued against it being the whole story [4].
Age and development. The child study's authors suggested the difference between adult and child findings may reflect changes around puberty [7].
🧪 Key takeaway: Shared family factors, a broader body-and-brain process, and body-position signals are all live ideas. None is proven, and some of the link may simply reflect who gets studied.
How it can show up day to day: fatigue, pain, sensory and body-signal differences
Some of the overlap is in symptoms that can belong to either side. In the UK clinic study, neurodivergent adults reported more symptoms of dizziness on standing and more musculoskeletal pain than the comparison group, and the number of hypermobile joints statistically accounted for part of that difference [1]. These symptoms were self-reported rather than measured, and the study could not show cause [1]. The Ehlers-Danlos Society lists fatigue, headaches, digestive problems, autonomic dysfunction, poor body-position awareness and anxiety disorders among the problems often seen with HSD [8]. In a large UK survey of adults with hEDS or HSD, autistic respondents reported more symptoms, more co-occurring physical and mental health conditions, and poorer health than non-autistic respondents [14]. That survey drew on people connected to a patient charity, so it describes them rather than everyone with these conditions [14].
Here is how that can look. You are 31, diagnosed with ADHD three years ago, and your medication helps you start your work. But by mid-afternoon you are exhausted in a way that feels physical, not mental. Standing up from your desk sometimes makes the room tilt for a second. Your knees and wrists ache after ordinary days, and you have rolled the same ankle four times this year. You have always filed all of it under "ADHD tiredness," and no one has ever asked about your joints.
Or: your autistic 15-year-old has always been called clumsy. She avoids gym class, says her hips hurt after walking around the mall, and melts down on days with a lot of standing and noise. You have assumed it was sensory overload, and some of it may be. But you also notice she can fold her fingers back further than anyone in the family, and her pain follows activity, not just loud rooms. Coordination differences can have several causes, including hypermobility, which our article on dyspraxia in autistic adults walks through for adults.
In both examples, a careful clinician would not try to decide which condition "owns" each symptom. Fatigue can come from ADHD, autistic burnout, poor sleep, low mood or an orthostatic problem, and anxiety can sit on top of any of them. If worry or tension is part of the picture, the GAD-7 screener is a quick way to put a number on it.
A practical rule of thumb, not a diagnostic test: notice whether a symptom tracks your body, such as standing up, physical activity, or use of a particular joint, or tracks demands and environment, such as noise, tasks, social load or a hard week. Body-tracking symptoms are worth raising with your physician. Demand-tracking symptoms are worth raising in an autism or ADHD evaluation. Many people will have both.
💡 Key takeaway: Fatigue, pain and dizziness can belong to either side of the question. Writing down when they happen helps each professional answer their half.
What this means for an autism or ADHD evaluation
What a psychological assessment can and cannot tell you
A good evaluation looks at physical health as part of the picture. UK guidance for adult autism assessment says to ask about past and current physical disorders and sensory sensitivities, and to consider coexisting physical conditions [15]. The same guidance advises against routinely using biological or genetic tests to diagnose autism [15]. UK ADHD guidance also asks clinicians to include physical health and coexisting conditions in the diagnostic process [16].
So a psychological assessment can tell you whether you meet criteria for autism, ADHD or both, note symptoms such as joint pain, dizziness or fatigue in your history, and recommend that you see your doctor about them. It cannot diagnose hEDS or HSD, and a hypermobility finding does not count for or against an autism or ADHD diagnosis. One research team also noted that questions about hypermobility symptoms can overlap with autistic traits such as motor and sensory differences [3], which is another reason the two questions need different methods.
When to loop in your physician
The NHS suggests seeing a doctor if you have several troublesome symptoms, and says you do not usually need to worry about a few symptoms that are not causing problems [9]. Here is a simple way to decide:
If you are flexible but have no pain, injuries or dizziness, there is nothing to treat, and hypermobility does not change an autism or ADHD question.
If you have frequent joint pain, joints that slip or dislocate, easy injury, or dizziness and a racing heart when you stand, see your primary care doctor and bring a record of when it happens.
If you are also wondering about autism or ADHD, pursue that evaluation in parallel. You do not need to settle one question before starting the other.
If you already have both kinds of answers, make sure each clinician knows about the other diagnosis, since needs may differ when both are present [14].
Questions to ask before you book an evaluation
Will the evaluation assess both autism and ADHD if both seem possible?
Will you ask about my physical health, including pain, fatigue, dizziness and joint problems, and note them in the report?
What developmental history do you need, and what if I do not have childhood records?
What will I receive afterward: a diagnosis only, or written recommendations, including whether to see a physician?
If something points outside your scope, such as a possible connective-tissue condition, will you say so in writing so I can take it to my doctor?
Our page on ADHD and autism testing in Tennessee explains how our evaluations work.
🗂️ Key takeaway: Bring the joint and dizziness questions to a physician and the autism and ADHD questions to an evaluation. Ask each one to put their findings in writing so the other can use them.
Next step: getting support
The connection between hypermobility, autism and ADHD keeps coming up because it is real enough to show up in clinics, registers and research reviews. It is also less tidy than it sounds. The strongest numbers come from people already in the health system, much of the autism link may run through ADHD, and no one yet knows why the conditions travel together. What you can do now is practical: treat flexibility on its own as normal, take troublesome physical symptoms to your doctor, and take attention, social and sensory questions to a clinician who assesses autism and ADHD.
Wondering if ADHD explains the pattern?
A structured ADHD evaluation can tell you whether what you're noticing is ADHD, something else, or both — and what would actually help.
Frequently Asked Questions
Is hypermobility linked to autism?
Studies suggest an association, but not a simple one. A 2025 review pooled studies of autistic samples and found joint hypermobility in roughly 22 to 31 percent of the people studied, with higher figures when it was examined in person. These are rates in research samples, not in all autistic people. In one large adult study, most autistic participants also had ADHD, and in the small group without ADHD the link was not statistically significant. Being flexible is not a sign of autism.
Is Ehlers-Danlos syndrome linked to ADHD?
There is a measured association. In a Swedish national register study, people with a recorded Ehlers-Danlos diagnosis were about 5.6 times as likely to also have an ADHD diagnosis as matched comparison people, though only 4.3 percent of them did. Case-control studies of adults with ADHD also find more joint hypermobility. None of this shows that one condition causes the other.
Is 'hypermobility-related autism' a real diagnosis?
No. It is not a diagnosis that autism or ADHD guidelines use. Autism is diagnosed from a person's developmental history and current pattern of traits, and UK adult autism guidance advises against routinely using biological or genetic tests to diagnose it. Some researchers have suggested that autistic people with hypermobility may form a distinct subgroup, but that idea is still a hypothesis.
Can a psychologist diagnose hypermobile Ehlers-Danlos syndrome?
No. Hypermobile EDS and hypermobility spectrum disorder are medical diagnoses, made from medical history and a physical examination against clinical criteria, with other conditions ruled out. There is currently no genetic test for hypermobile EDS. A psychologist can note joint, pain or dizziness symptoms during an autism or ADHD evaluation and suggest you see your doctor about them.
Should I get checked for hEDS if I have ADHD or autism?
Not just because of the diagnosis. Being flexible on its own is common and does not need treatment. It is worth seeing your doctor if you have several troublesome symptoms, such as frequent joint pain, joints that slip or dislocate, easy injury, or dizziness when you stand up. Bring a short record of what happens and when.
About the Author
Dr. Kiesa Kelly is a licensed clinical psychologist and the founder of ScienceWorks Behavioral Healthcare. A neuropsychologist by training with more than 20 years of experience in psychological assessment, she completed an NIH-funded postdoctoral fellowship focused on ADHD in both research and clinical practice, including research on cognitive control in ADHD. She has also trained in neurodiversity-affirming ADHD and autism assessment through individual consultation with Dr. Paige Victorine, PsyD.
Dr. Kelly earned her PhD in Clinical Psychology, with a concentration in Neuropsychology, from Rosalind Franklin University of Medicine and Science. She completed practica, internship, and postdoctoral training at the University of Chicago, the University of Wisconsin, the University of Florida, and Vanderbilt University. She is a psychologist, not a physician, and does not diagnose connective-tissue conditions or prescribe medication.
References
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4. 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;16:207. https://doi.org/10.1186/s12888-016-0922-6
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8. The Ehlers-Danlos Society. What is HSD? Accessed October 9, 2026. https://www.ehlers-danlos.com/what-is-hsd/
9. NHS. Ehlers-Danlos syndromes. Page last reviewed October 4, 2022. Accessed October 9, 2026. https://www.nhs.uk/conditions/ehlers-danlos-syndromes/
10. The Ehlers-Danlos Society. What is EDS? Accessed October 9, 2026. https://www.ehlers-danlos.com/what-is-eds/
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Disclaimer
This article is for informational and educational purposes only and is not a substitute for professional medical or mental health advice, diagnosis, or treatment. Hypermobile Ehlers-Danlos syndrome and hypermobility spectrum disorder are diagnosed by physicians, and online screeners cannot diagnose autism, ADHD or any other condition. If you have chest pain, fainting, or a joint injury, seek medical care. If you are in crisis or thinking about harming yourself, call or text 988, or call 911 in an emergency.