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UnderstandingWhy in FND body and mind belong together – and “psychological” does not mean “imagined”.
Body or mind? The question is wrongly posed. In FND the two belong together – as in almost every illness. And “psychological” is not a synonym for “imagined”.
As early as 1977, the physician George L. Engel described the biopsychosocial model: health and illness arise in the interplay of biological, psychological and social factors – not from a single cause (Engel 1977, Science). This applies to almost every condition. In Functional Neurological Disorders it becomes particularly clear.
FND is multifactorial. Usually several factors work together: a biological predisposition, physical or psychological triggers (such as an injury, an infection or a distressing situation) and mechanisms that maintain the symptoms – such as altered attention and faulty predictions of the brain (Aybek & Perez 2022, BMJ).
Important here is the difference between cause and trigger: the one, clearly nameable cause usually does not exist in FND. A trigger is the impetus that sets the symptoms in motion – but not the same as a solely responsible cause. The psyche expressly belongs to this – as one of these factors, on an equal footing with the physical ones. But it is neither the sole cause nor proof that “nothing physical” is present. The dispute “body versus mind” therefore leads astray – the two belong inseparably together.
“My doctor pushed me into the psycho corner” – many of those affected say this sentence themselves. Understandable, because behind it often lies the feeling of not being taken seriously. But the phrasing has a catch: it treats “psychological” as something derogatory – a corner into which no one wants to belong – and thereby unintentionally discriminates against oneself and others. Yet “psychological” is nothing shameful and no synonym for “imagined”: psychological and physical processes are the same biological event in the brain.
This feeling is reinforced by the often years-long doctor odyssey: many of those affected experience that their symptoms are not taken seriously or are dismissed as “nothing organic”. If the word “psychological” then falls, it sounds to many like “you are imagining this” – and the faulty equation psyche = imagined entrenches itself. It is exactly this equation that we want to dissolve. Our aim is to take the psyche out of the corner: psychological factors belong to being human – and make an illness not one bit less real.
Many of those affected go through a wearing search for a physical cause – one examination appointment after another, MRI, EEG, CT. It is often driven by the thought: “Only when something can be demonstrated is it real.” But this thought is not correct. A normal finding does not mean the condition is not real – it only excludes certain other causes. Today FND is actively established by typical positive signs, not by the mere absence of a finding.
In the usual examinations (for example the MRI), no structural damage as in a stroke is found in FND. But this does not mean that “nothing” is there: modern, functional imaging shows, at group level, changes in the function and connectivity of the brain (Bègue et al. 2019, NeuroImage: Clinical). A striking example: in a study involving the Kliniken Schmieder (Lurija Institute, Allensbach), people with functional (conversion) paralysis and healthy people who only feigned a paralysis showed similar but not the same activation patterns in the frontal brain – the functional symptoms are therefore not produced consciously (Hassa et al. 2016, NeuroImage: Clinical).
Important in all this: such imaging findings are so far correlations, not proven causes. Whether the observed changes cause the symptoms or are rather their consequence is scientifically not yet conclusively clarified; as a diagnostic test, imaging is (still) not suitable (Perez et al. 2021, NeuroImage: Clinical). But this much is clear: the symptoms are physically real – and not produced voluntarily.
That expectations change the body measurably is scientifically well established and long since no longer ridiculed. In the placebo effect, the brain releases the body’s own messengers – such as opioids and dopamine – through the mere expectation of an effect, and demonstrably changes its activity (Benedetti 2011, Neuropsychopharmacology). The flip side is the nocebo effect: negative expectations can really intensify symptoms (Colloca & Barsky 2020, NEJM).
Such self-fulfilling expectations (self-fulfilling prophecy) also play a role in FND: when the brain “expects” a symptom and directs attention at it, it can bring forth exactly that symptom. This is not imagination, but neurobiology – and at the same time an opportunity: because such patterns are in part learned, they can also be re-learned. This is exactly where treatment begins (Deutsche Hirnstiftung).
In short: body and mind are not opposites. FND shows, exemplarily, that symptoms can be at once real, physically felt and influenceable by experience, attention and expectation. Whoever understands this stops asking “real or imagined?” – and begins to ask: “How can we help?”
Further reading: a vivid case report from the University Hospital Bonn ↗ shows, using the example of a 13-year-old, why the artificial separation of “physical” and “psychological” must be overcome – and FND is at once real and treatable (PDF, in German).
⚕️ This article serves general education and does not replace medical advice, diagnosis or treatment.