Some More Thoughts on Functional Neurological Disorder

By David Tuller, DrPH

Last week I wrote a post on some of the signs used to diagnose people with “functional neurological disorder” (FND)–the phrase that has largely supplanted “conversion disorder” to describe neurological symptoms with no identified organic cause. In that post, I should have been clearer that I do not question whether people experience these symptoms. There is obviously a large group of patients with extremely disabling conditions that remain undiagnosed and in many cases likely cannot be diagnosed through current medical technologies.

My concern is the longstanding insistence of psychiatrists and neurologists that these patients have no physiological dysfunctions that could account for the symptoms, and that the symptoms were therefore psychologically induced–whatever exactly that would mean. The relatively recent adoption of the more neutral-sounding FND does not wipe out this history. As with conversion disorder, the newer category has vague and expansive boundaries, making it possible for clinicians to define more or less anything they have trouble diagnosing as FND.

The term ‘medically unexplained symptoms” (MUS) raises similar concerns. Many people have symptoms that remain unexplained. To take that as de facto evidence that they are unexplainable and by definition psychogenic is a leap of logic that ignores the possibility of future scientific and medical advances. Like FND, MUS might be a useful descriptive term of certain phenomena in some contexts. But it is problematic when MUS becomes a diagnosis used to shunt people into psychotherapy after a primary care consultation, as happens in the UK through the expanding program known as Improving Access to Psychological Therapies.

In addition to rebranding conversion disorder as FND, psychiatrists and neurologists have in recent years taken to analogizing these complaints to “software” as opposed to “hardware” problems. That is, major cerebral structures are viewed as comparable to “hardware” and the communications and other functions linking regions of the brain represent the “software.” And if software is the problem, the optimal solution would be to replace or reprogram it. Following this analogy, I guess emotions and cognitions and beliefs would be considered parts of the malfunctioning “software.”

Despite the popularity of the hardware/software meme among FND experts, this binary presentation of the science turns out to be pretty inaccurate. According to a review of relevant research published last March in the journal NeuroImage: Clinical, unexplained neurological complaints are in fact associated with measurable hardware” abnormalities across a number of regions of the brain. These findings would appear to contradict many previous claims.

The paper is called “Structural alterations in functional neurological disorder and related conditions: a software and hardware problem?” The authors conclude that the answer is yes. As they write, “While the framing of FND as a ‘software’ problem is well-received, this conceptualization may require more nuanced considerations. Emerging structural neuroimaging findings point towards a parallel ‘hardware’-related neurobiology in some FND populations.”

The authors also note that “it remains unclear whether structural abnormalities relate to predisposing vulnerabilities or consequences of the disorder.” In other words, they don’t have much idea what is causing which or how best to interpret the findings.

From a field that has spent a century or more vehemently denying any organic basis for complaints with no known organic explanation, this acknowledgement of “hardware” problems is rather remarkable. Leading voices in the FND domain should pursue major efforts to disseminate this news to patients, given its significance. Yet the high-profile and widely read ** website–created by a co-author of the “hardware review”–continues to describe FND in strictly binary terms that apparently no longer fit the emerging science.

*[In this sentence and another mention of this website below, I initially wrote “” instead of “” I apologize for the error.]

In a page on “causes,” the site includes this statement: “If you were a computer its [sic] like having a software problem rather than a hardware problem. If you have a software bug on your computer, it might keep crashing or work really slowly. You wouldn’t solve that problem by opening up the computer and looking at the components. You wouldn’t see anything if you did an x-ray of that computer…You’d have to solve it by reprogramming the computer, working out which programs were causing the problem.” The phrase “its [sic] like having a software problem rather than a hardware problem” is highlighted as a pull-quote on the page.

According to the recent “hardware” review, however, investigators have so far found quite a lot on that metaphorical computer x-ray. So perhaps looking at the “components” and not just the “bugs” in the “software” makes sense after all–contrary to the standard pronouncements of psychiatrists and neurologists as well as the current statement on

A commentary last month in JAMA Neurology raises similar concerns. In the essay, Harvard neurologist Matthew Burke reports that there is a “silent epidemic” of people with FND–and he highlights the (now arguably inoperative) hardware/software analogy. He cites the range of neuroimaging studies that provide “physiological explanations for once mysterious links between regions implicated in emotional processing and the generation of ‘physical’ symptoms (eg, pain, fatigue, weakness)”–but he does not specifically mention the reported findings of structural abnormalities.

Then he writes the following:

“Despite the growing scientific literature, there has been minimal shift in physician attitudes toward these patients. Physicians seem quite comfortable with the idea of structural brain lesions causing psychological symptoms, such as a frontal lobe stroke causing depression or a temporal lobe tumor causing delusions. However, the reverse causality of psychological factors (borne of the same substrate–neurotransmitters, neurons, and synaptic connections) leading to neurological or systemic symptoms is often hastily dismissed and remains highly stigmatized. Thus, many physicians either simply ignore these kinds of symptoms or wrongfully assume that patients are malingering.”

Burke comes across as a sympathetic clinician concerned about the well-being of patients, and his point about unacceptable or questionable physician attitudes is well taken. But perhaps it should not be surprising that many physicians ignore or misinterpret “these kinds of symptoms.” For more than a century, psychiatrists and neurologists have promoted the dogma that unexplained neurological complaints resulted from the unconscious conversion of anxieties and psychological distress into somatic manifestations, not from pathophysiological processes.

And Burke himself continues to insist on the primacy of “psychological factors” in FND. Yet the neuroimaging studies he cites document apparent associations. They do not and could not document his theorized “reverse causality of psychological factors.” (He acknowledges that these “psychological factors” are “borne of biochemical substrates,” but he leaves it at that; perhaps more analysis of that point would have been warranted.)

Given the long list of recognized diseases formerly attributed to “psychological factors,” the source of Burke’s confidence that such entities are “leading to” neurological symptoms is unclear. He could be right that there is a silent epidemic of people with misunderstood neurological disorders. But his analysis seems blind to the historical role that psychiatry and neurology have played in creating this misunderstanding in the first place with their entrenched practice of slapping dismissive psychiatric labels on patients that confound them.

(If these two disciplines actually want to demonstrate that they are moving beyond their biases, perhaps they should terminate the phrase “psychogenic non-epileptic seizures.” After all, the “hardware” review included reports of “reduced inferior frontal gyrus” and “altered orbitofrontal CTH [cortical thickness]” in these patients. For multiple reasons, it is hard to justify the continued use of the word “psychogenic” in this context.)





21 responses to “Some More Thoughts on Functional Neurological Disorder”

  1. Wendy Boutilier Avatar
    Wendy Boutilier

    MUS & FND provide the tool to write off the cruelty it inflicts.
    Pseudoscience includes beliefs, theories, or practices that have been or are considered scientific, but have no basis in scientific fact. This could mean they were disproved scientifically, can’t be tested scientifically, or lack evidence to support them. What’s next – Voodoo?

  2. CT Avatar

    So Jon Stone has known since last March or before about the ‘hardware’ issue but hasn’t bothered to let doctors and patients know via his website? That doesn’t seem very transparent to me, especially since the website is widely recommended (in the UK and overseas) to both doctors and patients.

    Thanks for this blog David, it’s important that ME sufferers understand what’s going on with FND.

  3. Richard Vallee Avatar
    Richard Vallee

    The big tell is the growing trend in the field of puzzling over why the patients reject the descriptions they give and how to better convince them of the superiority of those beliefs. The big “innovation” of FND appears to be lying to the patients in order to gain their trust, which is basically perfidy. It’s telling that the people who defend it as patients are confused over this, having been lied to, that it absolutely 100% means the same thing as hysteria, with one extra step of lying about it.

    Sorry but when a musician goes on stage and people are cringing and putting hands on their ears to stop the musical offense, the audience isn’t the problem. Maybe a different audience would be more receptive, but then that’s just a false solution in search of a problem, not how any of this is supposed to work. A full century of failure is straight up embarrassing at this point.

    None of us are not thinking anything particular or have any beliefs about the things these people obsess over, we have much better things to do. They just don’t seem to get the message because they broke the feedback mechanism, leaving them blind, thinking they’re nailing it as they’re getting booed. I’m sorry, I mean being boo-urnsed. Yes, that’s right, they are saying boo-urns. Nailed it, champs.

  4. @MECFSNews Avatar


    Please write an article on illnesses that were previously viewed as psychogenic but no longer are. An examination of how attitudes towards an illness change when it becomes viewed as organic would also be interesting.

    The de facto purpose of psychogenic labels appears to be to create a degrading narrative of the patient to justify their subsequent mistreatment (usually in the form of refusing to help them in any meaningful way, or by exploiting them with placebo treatments). This is how the label seems to play out in practice.

  5. Alicia Butcher Ehrhardt Avatar
    Alicia Butcher Ehrhardt

    And it’s so often male doctors telling women patients that their uteri are wandering. Women are far more likely to be treated as nut cases in need of a little paternalistic guidance (CBT misapplied, the Lightning Process). Since women are more likely to be diagnosed with ME/CFS, it compounds the lack of help they are dealt.

    I can’t wait for research to find the cause of ME – as the AIDS victims were waiting for the discovery of HIV and a treatment for it.

  6. Maija Haavisto Avatar
    Maija Haavisto

    Most cases of illnesses diagnosed as FND would be relatively easy to diagnose correctly if the doctors just bothered. E.g. a woman I talked to who was diagnosed with conversion disorder and insisted the diagnosis must be right. I told her she cannot have conversion disorder, as it does not exist. It is something else. It turned out to be MELAS. She had been told that MELAS and other mitochondrial diseases had been excluded, but it wasn’t true.

  7. Lady Shambles Avatar
    Lady Shambles

    CT, you mean the same Jon Stone who recently tweeted about the importance of being transparent in relation to FND - ?

    A man of his word! (Not! and therefore why trust anything else he says?)


    David: many thanks for this .. I know it’s the tip of a very large iceberg, but what with climate change etc even icebergs can’t hide their dangerous underbelly indefinitely.


    One thing that I feel needs airing wrt MUS and FND (and all synonyms) and the fight to unveil their perfidy is that there is only one honest and true ‘right’ in this discussion. For David and others like him who research this topic they have to contend with the weight and specificity of that truth. It’s not easy to find necessarily and it can’t be skewed when it has been found. In contrast the unscrupulousness of creating a fake dogma provides the perfect opportunity to alter and massage and create new ‘add-on’ bits of dogma at the flick of a wrist. We’ve seen the way the word to describe this dogma has changed over time… why?: purely to deceive those who challenge the dogma, be they patient or researcher. The BPS school can create at whim a whole new set of clothes, now complete with dodgy websites to convince the vulnerable they aren’t being lied to. Lying is easy… the truth is hard won.
    How did we come to this…. a massive, international, government-endorsed lying-machine, designed to malign the genuinely (bio-medically) ill and to throw them onto a scrapheap of cheap and very brief CBT and then into medical oblivion where every further medical problem is written off as psychogenic or hysterical..same thing.. just different clothes? How did this happen? Shame on us all as human beings that this could occur so willfully.

    ‘Flick of the wrist and you’re dead baby’ : thanks Freddie I think you’ve rather summed it up.

  8. CT Avatar

    Thanks for that Twitter link Lady Shambles – haha, Stone walked straight into that one, didn’t he? Transparency and sharing information with patients indeed! [I don’t think it’s the first time that someone’s come a cropper (on Virology blog) through what they’ve posted on Twitter.]

    So why wouldn’t he want to share the ‘hardware’ findings on his website? Well perhaps because it’s extensively used across the NHS and further afield to persuade doctors and patients that there isn’t any ‘hardware’ problem, that unexplained symptoms in neurology clinics are ONLY due to mind-body interaction. Stone used the same word ‘only’ here - at 4.30 to 5.00 mins to refer to FND patients ‘only’ having a ‘functional’ disorder, suggesting to me that he perhaps considers them less deserving of resources and/or care. In the video he goes on to say that a diagnosis of ‘functional’ disorder should only be made on the basis of positive signs, not just because tests results are normal, but as I understand it (from one of his own papers), there is no positive sign for non-epileptic seizures, only a negative one (-that there are no findings on EEG), and yet these seizures are included with FND. How exactly? And why have patients without the requisite ‘positive’ signs for FND and without comprehensive tests/assessments being done to exclude other neurological disorders, been told that they have/ probably have ‘FND’, been told to go to the website and effectively been shown the door by NHS neurologists? It looks to me like FND serves as a convenient waste basket diagnosis for neurologists within the NHS, and the site is a considerable aid to them in this. I might alter my opinion if Stone updated to prominently inform patients and doctors that changes in the brain’s hardware have now been found.

  9. jimells Avatar

    Comparing biology to digital computers only shows their complete ignorance of computers and near-complete ignorance of biology. Sometimes I find it interesting to think of cell biology as working a bit like an analog computer (examples: slide rule, Norden bombsight) that continuously “adds up” all the various cell signalling molecules .

    But since most people have little understanding of either biology or computers, it is useless to try to explain one by comparing it to the other. In other words, it’s all just handwaving and gaslighting to make the patient go away and be satisfied with a referral for CBT.

  10. TT Avatar

    Coming at this excellent latest update from a Lupus/ Sjögren’s/ connective tissue disease perspective -my concern about any medic diagnosing FND is that the risk of rare, hard-to-diagnose, under researched autoimmune diseases being diagnosed as this is potentially dangerous.

    As a Scottish citizen I’ve already seen one parliamentarian to point this out because, once diagnosed with “FND” (primary or secondary overlay) it is then nigh on impossible to get this diagnosis redacted here.

    We have no right to second opinions under the Scottish NHS and out of area referrals are no longer being allowed either. So, with diseases such as Lupus, Vasculitis and Sjögren’s often taking many years, even decades, to diagnose and with “FND” being fairly obviously overdiagnosed (I’ve had this confirmed by various charity helplines now) there is a real risk that serious physical and psychological damage occurs as conditions that cannot ever entirely be excluded, are overlooked by neurologists and psychologists.

    This kind of medical gaslighting is known by various online health communities, to cause medical PTSD – often leading to severe depression and isolation – and of course lack of any meaningful investigations. And with Jon Stone working as an honorary professor in a Scottish university hospital – neurologists here In this small country are probably the most likely to support his work.

    It is so important that rare diseases are identified and diagnosed and researched. In my view every diagnosis of “FND” hinders this most important research by causing people to fear visiting their doctors, often not reporting neuro symptoms which may be actually be neurological manifestations of systemic diseases. In fact one of the earliest manifestations of the terminal cancer, multiple myeloma, can be neurotical symptoms. But if cause these systemic diseases probably don’t appear in the misdiagnosis stats given out by researchers – usually neurology or psychology trained.

    So I think it’s also high time that the failure to acknowledge neuro symptoms, overdiagnosed as “FND”, but actually caused by very underdiagnosed and misdiagnosed systemic diseases and under researched drug interactions, got a mention in this international debate.

    David, if you’re ever in Scotland as part of your journalistic research – do please feel free to contact me via my email address because I’m really keen to meet and discuss the lack of scientific evidence behind this so-called disorder. It really concerns me that neuro symptoms are being attributed to a conversion disorder associated with hypochondria, hysteria and simplified using the hardware/software metaphor.

    We aren’t robots – everything is organic!!

  11. Snow Leopard Avatar
    Snow Leopard

    The Hardware/Software analogy is just mind-body dualism rebranded. Old wine in new bottles as they love to say…

    As jimells said, the Hardware/Software demonstrates ignorance of both computers and biology and is merely a form of handwaving (if the medical practitioner isn’t very smart) or gaslighting (if they are smart).

  12. Marion Brown Avatar
    Marion Brown

    This is most interesting altogether. Thank you David.
    I have been following a different path but have also come up against this FND ‘diagnosis’ being used – & more and more! I have written quite a lot about what our own lay research is showing up – and was interested to see one of my pieces show up on the S4ME site.
    It seems that FND is being used as a convenient ‘bin’ in which to cover up all manner of serious neurological damage … from a variety of causes. And not least from antidepressants & other meds (& dependence & withdrawal issues)….. which seem to be an extremely ‘contested’ issue…. Wonder why??

  13. Neurology Avatar

    Thanks for the blog about trial by error some more thoughts on functional neurological disorder, for more details visit :

  14. CT Avatar

    I noticed a comment on David’s Twitter thread that implied that comments on this blog here are unhelpful, self-centred and come from people who don’t have to live with the disabling symptoms that are associated with FND. To my mind, this is way off the mark, and I suggest that if the person who wrote it is reading this then they should seek more information and get to know more about people who are severely disabled and suffering horrendously with ME before wading in with such remarks. As far as I can see, nobody is belittling their ‘FND’ symptoms, and yet they appear to be belittling the experience of people with ME. FND IS relevant to ME sufferers since some or many will have been to neurologists in the course of their illness and been dismissed as having ‘FND’ or ‘MUS’.

    For those who don’t think that ME is related in any way to FND research, they should listen to this interview with David Perez - (29.40 to 33 mins) – describing how FND researchers envisage their next step to be comparing FND patients to patients with conditions that overlap, such as chronic fatigue, chronic pain, PTSD, and possibly depression. (Michael Sharpe is referred to towards the end in connection with CBT).

  15. Marion Brown Avatar
    Marion Brown

    I have previously had an email exchange with Jon Stone (early 2017) – after I had this piece published by GP View (GP View vanished without notice mid 2019).
    Jon Stone has a chapter in the book that I had referenced: ABC of Medically Unexplained Symptoms (Ed Chris Burton, BMJ publishing 2013) – and I asked if he would help to explore my observations and concerns. The email exchange was polite – but was ended quickly by him when he said that he could not discuss my concerns any further.
    I did write a further piece for GP View some months later:
    At the time of the email exchange (early 2017) I joined the online FND ‘mailing list’ so recently received notice of this upcoming 2020 conference, which may be of interest!?

  16. Marion Brown Avatar
    Marion Brown

    This is about neurological complications from prescribed drugs …. and from 2004…

  17. CT Avatar

    Thanks for the useful link, Marion. I think adverse drug reactions (ADRs) and withdrawal problems should be an important consideration in relation to unexplained symptoms but are often ignored by neurologists and doctors in general. A neurologist I saw failed to ask about what drugs/remedies I had been taking and refused to countenance that some of my problems could have been caused by an ADR to a common drug. It would be interesting to know if any papers/books etc present the information the other way around, i.e. list the potential neurological side-effects of specific drugs. I doubt that patients can rely on the patient information leaflets that come with their prescriptions when there appears to be a persistent problem of under-reporting of ADRs by doctors.

  18. TT Avatar

    Hi again David. I re-read what I wrote here and realise I should have edited it better before sending.

    So I thought I’d send another comment – this time one I wrote in reply to a person who was previously diagnosed with MS but has now had their diagnosis changed to FND – without any full investigations other then a brain MRI. They are wondering if this is legit – and asking why they haven’t been given a lumbar puncture and blood tests to exclude conditions such as Lyme and Lupus:

    “Hi there. Just to say that according to the chief proponent of “FND”, Jon Stone, this isn’t supposed to be a diagnosis of exclusion – it should always be made using certain diagnostic signs and tests such as Hoover’s, Romberg and tremor entrainment and also pin prick tests. These tests haven’t apparently been approved scientifically yet by the wider medical community. So the neurologist uses them at their own discretion – and this is controversial of itself.

    There is no black and white way to diagnose “FND” whatever they may tell you.

    But without a doubt you should have had these tests applied during consultations for a diagnosis of “FND” to be made according to honorary Professor Jon Stone.

    As well as this you should have up to date brain and neck MRI and lumbar puncture to exclude MS. Also you should have a full battery of autoantibody tests done and full blood count and inflammatory markers, B12 and Vitamin D. And even if these are all normal it’s still possible to have Sjögren’s, Lupus or Vasculitis and other connective tissue disorders such as EDS. I had to have my Sjögren’s confirmed by lip biopsy. Lupus sometimes needs confirming by kidney or rash biopsy. 30% of people with autoimmune disease are seronegative and these are often the people who initially present with neuro symptoms unfortunately. So we have “FND” being overdiagnosed where autoimmune diseases such as Sjögren’s take average of 4-7 years to diagnose. By which time permanent damage To organs and joints and even the brain may have occurred.

    Also mast cell activation disorder and Lyme should be excluded. As should all vestibular disorders if your balance has been affected.

    Only when all these have been excluded can a neurologist ethically begin to discuss the possibility of neuro symptoms being caused bf functional disorders.

    Depending on where you live I would certainly email or write to your present neurologist setting out this situation as it appears to you.

    Bear in mind that many neurologists give themselves plenty of wriggle room so they can always say you have MS and FND overlay ..ditto with rheumatic diseases such as Lupus and Sjögren’s.

    The thing about systemic autoimmune diseases is that once they are confirmed then it really has to be a rheumatologist, not a neurologist, who decides whether your underlying disease is active or not.

    As you can probably tell I’m not convinced that anyone can be safely diagnosed with “FND”/ conversion disorder even if other stuff has all been included and the neurologist’s own bag of tricks/tests have shown positive.

    If a person feels they do have a conversion disorder to explain their neuro or pain symptoms then this is a separate issue – but to my mind the scientific evidence is still lacking.

    I suggest that you search for a neurologist who doesn’t routinely diagnose patients with functional disorders if you possibly can. If you’re in the UK there are helplines such as Lupus UK and the Brain & Spine foundation and MS Society where they might be able to recommend a good neurologist in your area.

    Otherwise you could write a letter to yours explaining all this and demanding more extensive investigations. Or do both. This is what I’ve had to do.

    Record any colour changes, rashes or swollen painful joints and connective tissue if you have any.
    Best of luck!”

  19. RB Avatar

    David, good summary. In the UK FND advocates have links to the PACE team and the insurance industry. FND seems to be UK neurology’s preferred name for conversion disorder today. The advantage it has for doctors is that patents don’t realise its a psychiatric diagnosis. The UK government has been told by doctors that patients with functional disorders don’t deserve any help financial or medical. Of note in Scotland several health boards recently told a Scottish Parliament committee investigating ME/CFS that ME/CFS doesn’t exist letting FND take over in Scotland.

  20. TT Avatar

    RB is there any way you can think of to galvanise those in Scotland who want to campaign to come together and effectively resist this political move towards diagnosing everything and anything that isn’t obviously biomedical as “functional”?

    For my part I did lobby my former MP (SNP) in 2018 – and would be happy to lobby my new Lib Dem MP and MSP if I felt that this would be effective. But, from experience, I’m afraid that it would be a waste of my very limited energy.

    I think we need a UK/ Scottish investigative journalist who is as shrewd and is prepared to work with David to expose the profound rottenness and lack of science associated with “FND” over here. The NHS has too much of a vested interest in allowing people to be diagnosed having had no meaningful (but expensive) investigations.

    Then, once the F word appears on our notes, it is pretty much impossible to get it redacted. And this “FND” colours everything from the way our doctors see us to the way we see ourselves,

  21. RITA GACON Avatar

    I was NOT informed that a thigh muscle biopsy (1982), produced results of “2 B attrification/petrification of the nerve and muscle tissue”. “We can find nothing wrong with you”. Perfidy. Mendacity. Ignorance and bare-faced lies. The Neurologist at Queen Sq., informed me in July 1983. He was disgusted. I was damaged and could have retired, preventing further damage. from 1977 to 1983..