I have been struck by how often academics and clinicians writing about functional disorders feel the need to announce the death of dualism – aka mind-body dualism or even Cartesian dualism, depending on the author. It isn’t easy to understand what is meant exactly by this claim and I have been doing a bit of reading between the lines to clarify, at least for myself.
Dualism in philosophy
First, it is worth saying that Descartes understood the mind and body not as radically separate but as in some way highly integrated. Here he is in the VI Meditation on First Philosophy:
‘Nature also teaches me, by these sensations of pain, hunger, and thirst, that I am not merely present in my body as a sailor is present in a ship, but that I am very closely joined and intermingled with it, so that I and the body form a unit. If this were not so, I, who am nothing other than a thinking thing, would not feel pain when the body was hurt, but would perceive the damage only by intellect, just as a sailor perceives by sight if anything in his ship is broken.’
I now understand the mind to be coextensive with the body – the whole mind in the whole body and the whole mind in any of its parts.
Descartes was writing nearly 400 years ago, so it’s not surprising that the terms used in the debate have changed somewhat. Modern philosophy of mind concerns itself, in this context, with the nature of consciousness or intentionality and how subjective experiences are to be explained, and (typically) with the question of how such experiences are related to something physical in the structures and functions of the brain. I think it’s fair to say that philosophers (well, the ones I’ve read) regard the idea that studying the brain can sort this out as bordering on the absurd. Tim Crane for example suggests that in exploring the mind-body relationship we should stop “considering those options which frustrate our understanding of our minds – for example…that we should look for consciousness by inspecting the sticky fatty matter of the brain”. Putting it slightly differently, Galen Strawson comments that even accepting that “…the known phenomena of experience are wholly a matter of the physical nature of ordinary matter under mild conditions (the mild of special conditions that obtain in the brain), … the physics and neurophysiology of the brain don’t enable us to understand how this is so”.
Dualism in clinical thinking
Actually, I don’t think that “dualism” is being used, in the context of clinical writings about functional disorders, in the philosophical sense at all. Rather it refers to the idea that a comprehensive account should include both mind and body mechanisms as expressed here: “A dualistic mind-body understanding of functional neurological disorders (FNDs), also known as conversion disorders, has led to the view that the cause of the symptom should be either psychological (psychogenic) or physical (neurogenic-“organic”).” … “The authors argue that the conversion concept is consistent with recent neuroscientific research findings, and the model allows psychological and neurobiological concepts to be reconciled within a single account of FND that begins to resolve the dualistic mind-body dichotomy.”
In one sense this is not at all a new idea – we have known for a long time that brain states accompany mental states and no doubt this is what Tony David meant when he said that dualism between mind and body “went in the nineteenth century”.
Looking further at this idea…here is an anecdote from the memoir of Geoffrey Keynes, a surgeon who served in the Great War:-
“On one occasion, when I happened to be in my dressing station …. a message came that a gunner had been wounded and was lying beside his gun at the edge of the lake. Would I, please, come at once? I then experienced a feeling which it is hard to describe. It was my duty to walk immediately with stretcher-bearers from a position of comparative safety to a gun pit, which was being accurately shelled every few minutes. I ordered my legs to take me there, but at first they refused to move. My mind was equal to the ordeal, but another part of my brain declined to pass on the necessary instructions….”
Geoffrey Keynes The Gates of Memory 1983
Can we describe a mechanism whereby the brain declines to pass on the mind’s instructions? The dualism abolitionists would say – perhaps not perfectly but we’re getting there. I think that’s wrong, and here’s a different vignette to explain why. Suppose I am crying at a funeral and three friends are discussing my plight. A psychiatric friend says – he has been bereaved (a social state), and he is crying because he is grieving (a mental state). The neurologist standing next to her says – ah, but he is crying because of activation of a multi-component pathway in the brain that includes the anterior cingulate gyrus. Wretched dualists! says the third, can you not see that the mental state of grief causes activation of the neural pathway and you need both elements to answer your question? Apart from noting what odd friends I have, you might wonder if my anti-dualism friend is really contributing anything apart from putting the two accounts (psychological and neurological) into the same sentence.
Dualism in clinical discussions
This points to what I take it the end-to-dualism claim actually means in practice: not that we have resolved the mind-body problem nor that we can produce a genuinely unitary account of functional disorders – how could we without solving the mind-body problem? Instead it means that when we speak about functional disorders we know longer use highly-articulated psychological explanations for what is going on. We pull this off in one of two ways.
One approach is to drop the psychological altogether or to trivialise or marginalise it. We should understand instead that for functional neurological disorders the problem “lies within the brain and its complex networks” and we should communicate this to patients in ways that enable them to say to themselves “I have a real dysfunction of networks in my brain”. If we use analogies they should be mechanical ones like the computer hardware-software distinction, or other neurological problems like phantom limb.
The other approach is to use a sort of language mash-up, as in a recent review that summarised studies from neuroimaging, cognitive psychology, biological markers, and epigenetic studies to generate a model that “…allows psychological and neurobiological concepts to be reconciled within a single account of FND that begins to resolve the dualistic mind-body dichotomy”. This is a (well-meaning) fudge: What happens is that a faux-integrated accounts allows for a misleading impression that the psychological side has been properly worked out because the neural mechanisms associated with it are now better understood. It would better to say that there are likely psychological mechanisms at play and likely neurological mechanisms, and we don’t understand how the one acts on the other.
Dualism lives – in philosophy, in clinical practice and (hidden in plain sight) in the accounts we offer of functional disorders. Nothing to be embarrassed about, even if some people are made uncomfortable by thinking about psychological causes for illnesses.
Research and treatment should involve understanding why and not just how they develop
The group of clinical conditions that are now described as Functional Neurological Disorder (FND) used to be known by more uncomfortable names – hysteria, conversion disorder, or the hybrid hysterical-conversion. The change of terminology is welcome, although perhaps not its usage in the singular; after all the category brings together some quite disparate conditions.
With this change in terminology comes a change in the academic and clinical discourse. For the last century or so, the majority view has been that these functional disorders have psychological causes: how they develop comes about through a process of loosening and disconnection between usually connected functions that need to be co-ordinated for effective motor or sensory function – dissociation; why they develop is explained as a response to some sort of psychological conflict that cannot be satisfactorily resolved – the emergence of disorder representing either symptomatic breakdown or a defensive manoeuvre to contain the conflict.
A shift in emphasis
The current FND discourse is relatively uninvolved with ideas about why FND occurs. Its focus is on antecedents that seem relatively trivial psychologically and upon mechanisms of symptom production – the how. Modern approaches in neuroscience allow studies of the physiology of symptom production that give new meaning to older ideas like dissociation and somatosensory amplification and more recent ideas about interoception, helping to explain some of the specifics of presentation – how some symptom states are generated – or to suggest why some individuals are especially susceptible. Such research may yield interesting insights into the nature of these conditions and perhaps offers the future possibility of new therapeutic approaches.
A corollary has been a tendency to downplay the role of interpersonal factors in aetiology or maintenance: early or later life experience is hardly discussed as having a potentially meaningful relationship to onset or persistence of FND. Enthusiasts for a quasi-neurological cause for FND are keen to quote a systematic literature review1 which found that many people do not report severe life events as antecedents to onset. Three of the most widely used patient-facing resources2 lead on “problems with functioning of the nervous system” in their definitions of FND, while not offering the possibility that an important cause might be psychological. Psychological intervention, if any is offered, is focussed on overcoming barriers to social and physical rehabilitation and formal psychological therapy may not even mentioned as an option3-4.
There are apparent clinical benefits to this approach, which no doubt account for its current popularity. Most significantly it can facilitate engagement during consultations and thereby rehabilitation efforts, especially in those cases where a less medical-sounding diagnosis is “not well accepted by patients who feel that (it) implies that their symptoms are inauthentic…”5
Where does psychotherapy fit in now?
Against this background a recent systematic literature review6 has summarised evidence for the effectiveness of psychological therapies in FND – 12 studies of CBT and seven of psychodynamic therapy. Therapy trials ought to be a test of some of the ideas about causes of FND and its associated disability, because CBT sits mainly as an adjunct to rehabilitation whereas psychodynamic therapy is aimed at the interpersonal distress that, putatively, has a causal as well as maintaining role.
The results are, frustratingly but not surprisingly, inconclusive. Most of the studies are small and had methodological weaknesses that prevent us getting a definitive answer. The lumping together of participants with quite different clinical presentations makes it impossible to answer the question “what might work for whom?”. We don’t know what proportion of eligible patients will accept either therapy when it is offered in an encouraging and supportive way.
Even so, two results stand out from this useful and well-conducted review. The first is that psychotherapy, including psychodynamically-informed therapy, can be acceptable to people with a range of functional disorders. The second is that the CODES trial7 – by far the largest and best conducted in the field – produced a number of non-specific benefits in mood, wellbeing, quality of life and so on, but had no effect on the frequency or severity of the primary presenting problem which was non-epileptic (functional) seizures.
The discourse on FND needs to be rebalanced. A full formulation should include an understanding of psychological and social factors in the generation and maintenance of functional states – not just as coincidental co-morbidities or as natural consequences of disability but as meaningfully related to the disorder. Current evidence on life adversity is not robust enough to dismiss this possibility: severe threatening events are not what one would typically expect to find as the explanatory exposure in this context8, and life events interviewing is a blunt tool for exploring more nuanced interpersonal conflicts.
The framing of FND as primarily a problem of nervous system function may get in the way of this broader formulation, making it harder for people to discuss and understand the psychosocial aspects of their illness.
Caricaturing of psychological perspectives doesn’t help. If clinicians really say to their patients “It’s all in your head”9or describe them (presumably to colleagues) as work-shy hysterics10 then what’s needed is some re-education of those clinicians rather than reformulating functional disorders so that patients learn to say “I have a real dysfunction of networks in my brain”9. We must be careful not to collude with the stigmatising of mental health problems by a reluctance to acknowledge that they too are respectable states with which to be diagnosed. When I first started in medicine, patients were frequently not told they had cancer – as a way of avoiding distressing and uncomfortable consultations. Nobody accepts that now, but it feels as if that’s where we are with FND.
It is a mistake to believe that everybody wants a disease-like diagnostic label and not everybody is offended by sensitively handled discussion of psychological causes of physical illness. For example Markus Reuber and colleagues in Sheffield have shown, as does the latest literature review, that if care is taken with early introduction of the ideas then psychological therapy, even when informed by psychodynamic principles, can be delivered in brief and acceptable formats to people with functional symptoms. Of course not everybody will accept a psychological approach, but an early over-emphasis on mechanistic explanations and short-term goals in therapy just makes it more difficult to address important psychological and social issues at a later stage, if all is not going well.
Writing a little while ago, Anthony David11 talked about a happy “we’re-all-friends-together-let’s get-rid of Cartesian-dualism” camaraderie that pervades this field. He was talking about something a bit different, but it’s still true that “an end to dualism” won’t do to explain where we are now. Apart from the misunderstanding of dualism that the slogan implies, it’s wrong because what we need is more openness about discussing with patients the possible primarily psychological causes and treatments that are relevant in FND even if that may bring uncomfortable consultations – a part of the continuing confrontation of stigmatisation in psychological illness. These ideas need to be tested in careful clinical trials that allow for testing of the value of psychological formulation and intervention as a substantial rather than adjunctive part of treatment, and involve evaluation of mediators and moderators of outcomes that can help unpack the complex nature of this group of disorders. We should do no less – we are still a long way from understanding functional disorders and treating them effectively, and the prognosis for FND is certainly not good as things stand12.
Ludwig L, Pasman JA, Nicholson T, Aybek S, David AS, Tuck S, Kanaan RA, Roelofs K, Carson A, Stone J. Stressful life events and maltreatment in conversion (functional neurological) disorder: systematic review and meta-analysis of case-control studies. The Lancet Psychiatry. 2018 Apr 1;5(4):307-20.
Johns R. I feel I am missing a piece of the puzzle. BMJ. 2020 Apr 8;369.
Wong M. Telling me you don’t know is ok. BMJ. 2020 Jan 8;368.
Dimsdale J, Creed F, Escobar J, Sharpe M, Wulsin L, Barsky A, Lees S, Irwin M, Levensen J (2013). Somatic symptom disorder: an important change in DSM. Journal of Psychosomatic Research, 75, 223-228.
Gutkin M, McLean L, Brown R, Kanaan RA. Systematic review of psychotherapy for adults with functional neurological disorder. Journal of Neurology, Neurosurgery & Psychiatry. 2020 Nov 5.
Goldstein LH, Robinson EJ, Mellers JD, Stone J, Carson A, Reuber M, Medford N, McCrone P, Murray J, Richardson MP, Pilecka I. Cognitive behavioural therapy for adults with dissociative seizures (CODES): a pragmatic, multicentre, randomised controlled trial. The Lancet Psychiatry. 2020 Jun 1;7(6):491-505.
Kanaan RA, Craig TK. Conversion disorder and the trouble with trauma. Psychological Medicine. 2019 Jul;49(10):1585-8.
Burke MJ. “It’s All in Your Head”—Medicine’s Silent Epidemic. JAMA Neurology. 2019 Sep 16.
Popkirov S, Baguley DM, Carson AJ, Brown RJ, Stone J. The neurology of the Cuban” sonic attacks”. The Lancet Neurology. 2019 Sep;18(9):817.
David AS. Functional disorders, Cartesian dualism and stigma: where does the dualism really lie? Journal of Neurology, Neurosurgery & Psychiatry 2012;83:869.
Edwards MJ. Functional neurological disorder: an ethical turning point for neuroscience. Brain 2019 Jun 26;142(7):1855-7.