What Does Neuroscience Tell Us About the Conversion Model of Functional Neurological Disorders?, 2019, Cretton et al

[Andy]

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”). One of the most influential psychological approaches is the Freudian model of conversion, which suggests that FNDs arise from a defense process in which emotional stress is converted into physical symptoms. This conversion theory has been challenged in recent years, accompanied by a shift in emphasis toward neuropathophysiological models of FND and away from historical psychological concepts. In this review, the authors consider the contemporary relevance of the conversion model from the neuroscientific perspective to reconcile the role of both psychological and biological factors in FND. A narrative review of recent neuroscientific findings pertaining to the conversion model of FND, encompassing neuroimaging, cognitive psychology, biological markers, and epigenetic studies, was performed. Research on the role of psychological stressors is discussed. Neurobiological mechanisms of repression of traumatic memories and their translation into physical symptoms are then explored. Finally, the role of physical symptoms as a potential protective defense mechanism against social stressors is considered. 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.

Paywall, https://neuro.psychiatryonline.org/doi/10.1176/appi.neuropsych.19040089
Not currently available via Scihub.

 

[Mithriel]

So there are people out there who still think that the drug addled theories of a nineteenth century quack have relevance to modern science?

CS Lewis, professor of literature, spoke about talking to a scientist in the 30's. They were discussing Freud and Lewis said that Freud's views on literature were rubbish but he supposed his ideas on science must be significant. The scientist looked taken aback and said that he had always thought Freud's science was dreadful but his views on literature must be sound.

 

[shak8]

Hang on, when a psychiatric disorder is clearly predominant, don't lump it into this FND category. Just because every generation has to rearrange its categories due to new science or just the need to move the furniture around and write papers about it, no reason to throw out good science and good clinical judgement.

I would really start to worry when Munchausen's Syndrome by Proxy falls into the FND drawer, and the kid isn't saved.

 

[SNT Gatchaman]

Functional neurological disorder or conversion disorder (here referred to FND) is a neuropsychiatric condition in which patients experience neurological symptoms, such as motor dysfunctions (e.g., limb paralysis, tremor, and gait disorder), nonepileptic seizures, or sensory symptoms, in the absence of classical neurological disease (i.e., without experiencing a stroke, inflammatory or neuroinfectious disease, etc.)

In this perspectives article, we focus on the question of why FNDs develop in certain individuals, with a particular focus on the role of stressors as a potential risk factor for, or precipitant of, the condition as part of the historical Freudian “conversion” model. The idea that psychological stressors are central to the etiology of FND has a long history in neurology and psychiatry, and these conditions continue to be described as “psychogenic” by many practitioners. Nevertheless, it has become apparent that FND is likely to have multiple triggering and predisposing risk factors, and in clinical practice, many neurologists and other medical clinicians are often unable to identify a specific stressor in their encounters with FND patients.

we revisit the role of psychological stressors in the development and maintenance of FND from the perspective of contemporary neuroscience and demonstrate that the role of psychological factors does not need to be opposed to biological mechanisms in FND.

In these respects, conversion can be thought of as serving a protective function from the emotional and environmental stressor (and can thus be viewed as an “adaptive” mechanism). The downside of this process is that it renders the individual unable to recognize, acknowledge, or process the underlying conflict, resulting in a disabling, often chronic, functional symptom (making it a “maladaptive” mechanism).

Subsequent developments of the conversion model have emphasized this inability to symbolize (i.e., mentally represent) the affect associated with adverse events as an important feature of people with functional neurological symptoms, so-called alexithymia (literally translated as “no words for feelings”).

What, so if I don't feel it's necessary to describe "the issue" in words, because it's just not that important to me, that's the pathology? Proven? Amazing.

It may be that some patients do not readily recall or recognize adverse life experiences; others who accurately report no history of abuse may have experienced other significant life events or stressors that are not captured by typical trauma measures or that they do not personally characterize as trauma. These events include losses of family or friends (or even significant pets for some)

Reaching much? "Please inform us of your trauma. Please."

37% of patients with FND reported physical events immediately prior to FND symptom onset (including injuries of the soft tissues or fractures, flu-like infectious illnesses, a neurological illness such as Bell’s palsy migraine, acute pain, drug reactions, surgery, or syncope), increasing to 80% of patients reporting events in the 3 months before symptom onset

So you can't find psychological causes and in fact most patients have physiological pathologies. Don't let that stop you though.

Does this mean that FND is a “psychogenic” or a “neurogenic” disorder? In our view, the answer is: both. To suggest otherwise, even to frame this as an “either-or” question, implies a dualist position that FND is either all psychological—that is “in the mind”—or all biological— that is “in the body.”

Is it A or B? It's both. If you suggest it's not both — even if you ask the question (as we just did at the beginning of the paragraph - oopsies - I guess we're dualists), implies that you are asking whether it might be A or B. That would be really, really bad. You mustn't do that.

 

[Trish]

You've got me laughing and groaning simultaneously, @SNT Gatchaman. Does that make me a dualist?

Seriously though, this is exactly what they do with ME/CFS. Even when evidence is staring them in the face they keep insisting on psychiatric/psychogenic/psychosomatic explanations.