*Kim H, a FND patient with whom I have frequently exchanged views, has left a comment below. I urge others to read it. I disagree with her interpretation, but I certainly think she has a right to express her perspective. However, I stand by my post.
**********
By David Tuller, DrPH
For years*, experts in functional neurological disorder (FND) have categorically asserted that the condition is strictly a “brain network” disorder, representing an issue solely with the brain’s so-called “software,” or functioning, rather than its “hardware,” or structural elements. According to this framework, structural elements of the brain, or other organic or pathophysiological processes, played no role in causing the condition. [*I initially wrote “decades” and have corrected it.]
The well-known FND website, neurosymptoms.org, has long popularized this notion—and continues to do so. The site currently proclaims on its home page that FND is “caused by a PROBLEM with the FUNCTIONING of the nervous system” and that it is “a ‘software’ issue of the brain, not the hardware (as in stroke or MS).” From this perspective, the “hardware” is irrelevant.
Given this view, anyone suggesting that the etiology of FND might involve something other than “software” problems or malfunctioning brain networks has been routinely dismissed as engaging in “dualistic” thinking. As I understand it, the purported “dualism” involved the belief that somatic symptoms were likely caused by unidentified pathophysiological dysfunctions, not just aberrant brain “software.” This accusation of “dualism” always struck me as backwards, since it was the FND proponents who themselves advanced the rigid “software” vs “hardware” dichotomy. Isn’t it “dualistic” to argue for a complete split between “software” and “hardware”? Or am I the confused one here? (I assume the FND folks would say yes.)
Whatever. In the introduction to a recent collection of papers on FND in the journal NeuroImage: Clinical, the authors flatly acknowledge that the “software”-only hypothesis is dead. (I’m not they would express themselves that way—but the admission is obvious to those outside their bubble.) That paper, called “Brain imaging research is thriving in functional neurological disorder,” offers this conclusion:
“Observations continue to support that FND is in part a problem of alterations within and across multiple brain networks…The data for FND representing a “software” and “hardware” problem of the brain is also growing.”
The evidence of “hardware” involvement has been growing for years alongside the “software”-only hypothesis. But you don’t need to be a neuroscientist, or even a native English speaker, to know that this new paper’s conclusion is not remotely compatible with the persistent claims over many years, on neurosymptoms.org and elsewhere, that FND can be completely attributed to “software” and brain network problems. To argue now that FND is merely “in part” a brain network issue–and how big a part is that, anyway?–and to note that “hardware” also likely plays a central role in the condition is a pretty sharp turnaround from the past.
I mean, either “hardware” is involved, or it’s not. Both can’t be true. And the FND field seems pretty confused about which one it is—despite the history of definitive claims regarding the exclusive role of “software” problems and dismissive attitudes towards those challenging that view. (As a sign of the confusion, neurosymptoms.org includes a separate section on the emerging evidence of “hardware” changes, but for unexplained reasons has not altered its conclusions on its home page about the exclusively “software” nature of FND.)
Let’s be clear. This “software”-and-“hardware” proposition marks a huge change in the framing of FND. For many years, we have been told ad nauseam that FND was solely “a problem of alterations within and across multiple brain networks.” There was no “disease.” The only issue was “software” that needed fine-tuning and retraining with treatments like cognitive behavior therapy and physical rehabilitation. Given that, FND experts have struggled to make sense of the emerging reports of structural changes as well, suggesting that they might be downstream consequences of the “software” issues.
Now we have a clear acknowledgement that the “software”-only hypothesis is no longer operative. That raises a critical question: If “hardware” or other pathophysiological factors are potentially at play in causing the devastating symptoms that characterize FND, what makes the condition “functional” in the first place?
In medicine, “functional” has become popular as a seemingly neutral replacement for words like “psychosomatic” and “psychogenic,” which patients perceive as insulting. “Functional” illnesses have also frequently been called “medically unexplained symptoms”—meaning that they resist ready biomedical explanations, whether because of their very nature or our current limited state of knowledge. If it now appears that biomedical or “hardware” factors are part of FND’s causal pathway, then “functional” is likely a misnomer.
The generally favored treatments for FND and other so-called “functional” conditions have been psychological and behavioral interventions. In FND, these treatments have been designed to target the purported brain network issues said to be causing it. Unfortunately, major randomized clinical trials, including for functional seizures and functional motor disorders, have yielded poor results for their primary outcomes, raising self-evident questions about the rationale for the interventions.
These disappointing findings do not appear to have shaken the confidence of FND experts in the correctness of their strategies or led to greater humility in their pronouncements. Instead, they have generally explained away these disappointing results by citing personal clinical experience and engaging in contorted reasoning. But perhaps these interventions failed because, as the most recent paper notes, FND is only “in part” a brain network disorder.
One of the problems with the longstanding FND claims involves a simple fact: brain scan research is still in its infancy. Functional magnetic resonance imaging (fMRI) documents brain activity, but the findings represent associations only; interpreting them as causal, as FND experts routinely have, is fraught with peril. After all, everything we do involves differential brain networks; the phenomenon is not somehow limited to people experiencing FND. Causal claims derived from these scans are speculative and theoretical and should not be presented as fact. Maybe all the “software” issues are being caused by the “hardware” ones. Seems like no one much knows at this point. The issue is up for grabs.
Anyone (like me) who has challenged the “software”-only construct has been harshly criticized by FND proponents for…well, I’m not quite sure. I have pointed out serious weaknesses and logical flaws in FND studies and have suggested multiple times that “hardware,” organic or other pathophysiological factors could play a causal role. I’m glad to see the FND field has–finally–reached the same conclusion. Too bad it’s taken so long.
What I’ve always found striking is that neurology treats “functional disorders” quite differently from how other medical specialties handle theirs. To the point that the classic, historically understood meaning of a “functional disorder”, even though the term is used in neurology, technically no longer exists in the field. This redefinition is precisely why we’re seeing so much confusion right now.
Firstly, let me correct the opening sentence.
“Software-only” appears to be your construction, not an established specialist position. If you are claiming that FND specialists have argued biology, pathophysiology, brain structure, or the body are irrelevant to FND, it would be helpful to cite where that has been stated. The “software/hardware” analogy has been used as a simplified patient-facing metaphor to distinguish altered nervous system functioning from visible structural damage or disease patterns, such as stroke, MS or tumour. That is very different from claiming FND is “software-only”.
“For decades” is also misleading. The modern “brain network” framing of FND is a relatively recent development in FND neuroscience, not a decades-old fixed doctrine.
I agree, the analogy is imperfect. Many of us in the FND community have discussed this for years. But there is a difference between saying “this is not explained by visible structural damage or disease patterns” and saying “there is no biology involved”. Those are not the same thing.
By differentiating between “software” and “hardware”, specialists are usually trying to explain function versus visible structural damage. That does not mean the “hardware” is irrelevant. Of course the brain and nervous system are involved. All illness relates to the body in some way. FND symptoms do not float around outside biology.
The discussion of dualism here is also confused. No one is being “dualistic” simply because they think biology or pathophysiology may be involved. The dualism problem is the old binary that symptoms must be either physical or psychological, organic or functional, real or not real. FND is exactly where that binary fails.
The interpretation of “functional” here is also too narrow. Functional does not mean “not biological”, “not real”, or simply a neutral replacement for psychogenic or psychosomatic. Those terms are increasingly obsolete because they imply a psychological origin that modern FND framing does not require.
“Functional” refers to altered functioning of the nervous system, and that meaning predates the later Freudian/conversion-era shift toward psychogenic explanations. Historically, “functional” distinguished problems of function from visible structural disease. The word carries historical baggage and is often badly explained, but it does not mean an absence of biology or pathophysiology. It means symptoms are not explained by the kind of visible structural lesion or damage pattern seen in conditions such as stroke, MS or tumour.
So asking whether “hardware” is involved creates a false drama. Of course the brain and nervous system are involved. FND symptoms do not float around outside biology. The issue is whether symptoms are explained by structural damage in the way the analogy is trying, imperfectly, to distinguish.
This post treats emerging nuance as if it is some major reversal. It is not. FND patients have been talking about poor analogies, comorbidities, misdiagnosis, service quality, language, and the limits of current explanations for years. We do not need outsiders to announce this as if they have discovered something the community has missed.
There are fair criticisms to make. Treatment evidence is mixed. Some explanations have been oversimplified. The software analogy is not good enough. But this does not read as concern for FND patients. It reads as FND being used as another route into long-running disputes with particular clinicians and researchers. Meanwhile, the actual FND community is spoken about, not engaged with, and left to deal with the confusion these framings create.
As someone with FND and someone who has spent years engaging with the FND patient community, this is why my biggest issue is representation. Who is “we” here? Because it is certainly not the FND community. You do not engage with us, you do not represent us, and yet you repeatedly comment on FND in ways that are then amplified by people already primed to distrust the diagnosis.
That causes harm. It increases stigma, confusion and fear around a recognised neurological disorder that many patients already struggle to have taken seriously.
Critique is fair. But commentary about FND should not speak around the patient community whilst pretending to speak with authority about what FND means for us.
This reminds me of what struck me as substantial inconsistency around “Havana Syndrome”.
On the one hand, research into this syndrome apparently turned up little or nothing in the way of significant findings from brain scans, -https://edition.cnn.com/2024/03/18/health/havana-syndrome-studies/index.html
which, if I’m not mistaken, included functional MRI scans -https://jamanetwork.com/journals/jama/fullarticle/2816532
but, on the other hand, this paper – https://neurologytoday.aan.com/doi/10.1097/01.NT.0001024552.68817.b1
documented 28% of participants as having PPPD which is considered a sub-type of FND (see here -https://www.thelancet.com/journals/laneur/article/PIIS1474-4422(21)00422-1/abstract).
How does that up when PPPD researchers have reported brain changes on MRI?
For example, this review paper -https://link.springer.com/article/10.1007/s13139-020-00675-2 , from 2021, – seems to suggest that significant detectable brain differences have been found in PPPD patients?
I suppose it’s possible that the researchers investigating “Havana Syndrome” didn’t use the same functional MRI techniques/protocols as the studies in that review but, if that was the case, then I’d wonder why not when they should have been well aware of techniques and advances in the field.
To my mind, the field of FND is in a complete mess, exemplified perhaps by this recent paper -https://www.sciencedirect.com/science/article/pii/S0035378726004479 which, like so many others in the field, appears to relay some pretty confusing messages about FND. My guess is its authors would genuinely like to reduce confusion and inconsistency of messaging around FND but they seem blissfully unaware that their own paper adds to that confusion by employing prevalence information obtained at a time when FND was considered to be synonymous with medically unexplained symptoms and, as such, a diagnosis of exclusion. You don’t have to be a brain surgeon to realize that you can no longer rely on old prevalence data (obtained by employing an old definition) after substantial changes to the definition of an illness have been made.
And if leading FND proponents believe that they have the right to weigh in on ME/CFS e.g. -https://jnnp.bmj.com/content/94/12/1056 and also on Long COVID e.g. -https://newrepublic.com/article/168965/might-long-covid-wrong then why shouldn’t David criticize the field of FND? They don’t appear to be showing any signs of stopping, so why on earth should he?
CT – this is precisely a problem I am highlighting.
Your comment shifts the issue away from whether the framing of FND is accurate and into a wider dispute about ME/CFS, Long Covid, BPS, PACE, CBT, GET, particular clinicians, etc. That is exactly what keeps happening. FND is repeatedly pulled into other people’s battles, whilst the actual FND patient community is treated as incidental.
That does not centre FND patients. It makes us collateral in a wider fight.
It seems that the FND move to try to incorporate “hardware” into their lexicon is a move to validate the illness by including the biology. To biologise the psychology – but yes this means that they started with a dualistic viewpoint. But they are in a Möbius loop of attempts of conviction. The software metaphor (and what good medicine only runs on metaphor! Telephones, radar, telegrams have all had their moment.) was also an attempt to obscurate from the toxicity of psychosomatic framing and that they thought it was non organic.
But really it’s still a mess.
Kim Hearne: “shifts the issue away from whether the framing of FND is accurate and into a wider dispute about ME/CFS, Long Covid, BPS, PACE, CBT, GET, particular clinicians, etc. ….. FND is repeatedly pulled into other people’s battles ….. “.
You’ve got it back to front Kim. ME/CFS, Long Covid, and multiple other diseases are being systematically and unwillingly shoved under an ever-expanding FND umbrella by the likes of Jon Stone, Alan Carson, and the newer generation of FND Drs, who all appear to be on an Empire Building quest. Lots of us were familiar with Stone’s work way back in the early 2,000s when he was all about ‘Medically Unexplained Symptoms’ ie psychosomatic, before he, Carson, Sharpe etc settled on the FND name. See ‘What should we say to patients with symptoms unexplained by disease? The “number needed to offend” 2002.
ME and Long Covid patients want nothing to do with FND. Jon Stone, Alan Carson et al are making ME and Long Covid patients collateral damage in their relentless expansion of FND, and their dangerous use of it as a bolt-on diagnosis. ME/CFS patients are finding FND popping up all over their medical records, often the diagnosing Drs don’t even tell the patients they have been rediagnosed or given a bolt-on diagnosis of FND.
Is there any illness diagnosis on the planet that cannot have FND bolted onto it because FND adherents “see it everywhere”.
I don’t think my measly second comment above has the power to shift the matter away from the accuracy around FND framing and into a wider dispute. No, I’d say that it was those FND proponents – the ones who co-authored the two papers I linked to, who stepped outside their FND specialism to interfere in ME/CFS and Long COVID – who did that, and so any blame around that should rest with them.
My son, a rookie neuropsychologist, suggested I might have FND, after various tests failed to uncover the source of neurological issues, some of which followed shingles/COVID co-infection in 2020, others after whiplash injuries (x2). I suspect that the diagnosis is limited to the capacity of the available investigation, and may yet show up. It is quite bizarre that “duality” is rejected, especially where there are obvious sources of injury/infection. Lazy clinicians are the ones who tell you symptoms are effectively all in your head.
If FND is no longer a diagnosis of exclusion, (since 2013, wasn’t it?), then why is misdiagnosis information still being provided for FND that is based on studies that identified patients by exclusion e.g. in this paper from 2 years ago -https://www.sciencedirect.com/science/article/pii/S0022399924000795?via%3Dihub (see the discussion section)? You don’t have to be a brain surgeon to realize that you can no longer rely on old misdiagnosis rates (obtained by employing an old definition) after substantial changes to the definition of an illness have been made. Old prevalence rates, old misdiagnosis rates, and now the software vs hardware analogy that apparently no longer stands up. Why the reluctance to let go of the past?
I came here to say something but Louisa said it brilliantly. I do however, want to commend Kim on her thoughtful post and say I deeply empathise with the ‘nothing about us, without us’ point.
I am all for increasing nuance in discussion and debate but I do feel, as someone who has had to fight my GP, among others, not to give me an FND misdiagnosis or as Louisa correctly described it ‘bolt-on’ diagnosis, it is the desire of clinicians from the bottom to the top (but especially at the top- Jon Stone, Alan Carson) to suck all PAIS related illness and disease into their FND empire that is the root cause of these upsetting collisions.
I know you know this but it bears repeating- It is their insistence on delegitimising the tsunami of biological research into the disease processes involved in ME, and the insidious way they have manipulated BPS research and public discourse around ME and Long Covid that deservedly causes ire amongst our community. I feel I might say to them, what you have said to David. They don’t speak for us, yet their few voices have dominated the conversation about us, costing lives. There is no consequence for them, as they continue to gather high positions and accolades – the injustice is jarring.
To me it seems as though we are all the victims of careerists who make their names off the back of our suffering. There have long been unethical connections between this small group of psychiatrists and health insurance companies. Political reasons to avoid conceding that the government engineered fraudulent research and allowed a mass disabling event to occur (and continue) or to avoid the inevitable cost of appropriate treatment, provision of clean air or admit that the 2 million people who have left the workforce may well largely be the same 2 million people who now have ME and Covid related ME in the UK.
I understand that two wrongs don’t make a right, but very few people have stuck their heads above the parapet to speak for up us, and the almost conspiratorial way this disease has been treated in this country for the last 30-40 years. David has been phenomenal in highlighting the issues and our plight. His dedication and persistence has been one of the key reasons the conversation is changing, globally around ME and LC. His eye for detail and clarity is unparalleled. Despite your dislike of his simplified or blunt explanations, he is, to many of us, nothing short of a hero, with his no nonsense accessible style of writing. By which I mean, one doesn’t have to be a scientist to understand the key issues.
All that said, I wish you recovery and peace, or at the very least remission, whatever that looks like for you and hope that one day our two communities can fight together against misinformation, discrimination and other associated poor treatment. We both deserve better.
I first met the Software analogy in the 1990s. This was from a doctor who believed in Hysteria. The point he was trying to make was that there was nothing wrong with the ‘hardware’ i.e. the body and fixing the mind was the cure.
We had a long discussion. It was obvious he had no idea what he was talking about. No IT training or even a clue about networks, different types of memory or how computers work.
The same idea has come up over and over again over 20 years with a monotonous regularity.
They didn’t understand bodily systems either and any advances on the science is very slow. It was simply a glib way of trying to explain their belief.
For me it showed how they would try and use ‘science’ to justify their beliefs even if it wasn’t true.
It’s too late to backtrack and pretend it didn’t happen. Too many of us have heard it.
In regards to Kim Hearne’s comment:
I understand your why you see it that way, but it’s only freshly educated FND specialists that no longer explicitly frame FND as “purely psychological” or claim biology is irrelevant. There’s still plenty of old traditional neurologists out there.
The central concern we have is what happens after an FND diagnosis is given.
In real clinical settings, the diagnosis often isn’t a recognition of a complex nervous system disorder. (Especially an ME/CFS yet they still give us that diagnosis even though the disease is not FND) Instead, the diagnosis acts as a signal that biomedical investigation has reached a dead end.
Once ‘FND’ appears on a medical record, further investigation largely stops. Symptoms are psychologised, other specialties dismiss the patient, and clinicians inside and outside of neurology default to assuming anxiety, trauma, or behavioural drivers are at play, even without evidence. Medical gaslighting at its finest.
Uncertainty is turned into diagnostic certainty. That is where the distrust originates.
While modern FND theory may no longer require symptoms to be psychogenic, language carries baggage.
Historically, medicine has routinely labelled poorly understood illnesses as ‘functional’ before discovering their biological mechanisms.
When patients are given this label without biomarkers, they hear ‘medicine does not know, but is assigning meaning anyway.’
If the field believes it has moved beyond older psychosomatic models, it must reckon with why clinical culture and patient experience still reflect those assumptions.
Most clinicians in other fields still interpret FND through an outdated psychological lens, and the diagnosis directly affects how seriously symptoms are taken.
Having a FND diagnosis also creates real barriers with insurance and welfare systems, limiting access to support and care.
Criticism should not be dismissed as outsiders ‘speaking over’ the community.
Many FND diagnosed patients, including myself, raise these concerns too. This is a broader problem in how medicine handles uncertainty and how these labels shape care and access beyond neurology.
By shifting to a ‘software and hardware’ model, neurology is tinkering with the edges of a failed hypothesis.
If structural factors are causally involved, the ‘functional’ label no longer holds, which helps explain why targeted behavioral treatments have failed.
.
For decades, patients were told their symptoms were not biologically real while structural factors were likely at play. Patients lost years of proper treatment, were dismissed by doctors, denied insurance and disability support, and made to feel crazy.
Now that evidence has forced neurology to admit hardware matters, we get a quiet sneaky redefinition. Not a new name for the new model. So the stigma sticks.
And here is the real disgrace… they have not apologised. “No apology from neurology” (and I looked for apologies, and there’s none). No courage to say “we were wrong, the functional label was a mistake, we are retiring it.” Instead they tinker with the model to save face.
Also very little effort to educate the wider medical community outside of modern neurology that FND has changed its meaning. (I looked that up too). It’s so glaringly obvious what they are doing.
That is utterly appalling behaviour from a profession that expects patients to trust it. I certainly don’t trust them.