Why should ‘psychogenic’ be parenthetical in functional (psychogenic) neurological disorder?

Abstract

Future NeurologyAhead of Print CommentaryOpen AccessWhy should ‘psychogenic’ be parenthetical in functional (psychogenic) neurological disorder?Laurent Vercueil & Christo BratanovLaurent Vercueil *Author for correspondence: Tel.: +33670316120; E-mail Address: lvercueil@chu-grenoble.frhttps://orcid.org/0000-0003-3323-0091Laboratory of Psychology and Neurocognition, Université Grenoble Alpes, 38000 Grenoble, FranceNeurology Department, CHU Grenoble Alpes, Grenoble, FranceSearch for more papers by this author & Christo BratanovNeurology Department, CHU Grenoble Alpes, Grenoble, FranceSearch for more papers by this authorPublished Online:2 Nov 2023https://doi.org/10.2217/fnl-2022-0018AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinkedInRedditEmail Keywords: functional neurological disorderpsychogenicFunctional neurologic disorder (FND) refers to a group of common neurological symptoms arising from the voluntary and conscious motor or somatosensory nervous system but experienced as involuntary. In FND, there is no significant structural damage in the brain, or the damage is unrelated to the symptoms. The exact cause of FND is unknown. A substantial amount of debate has risen in the recent literature about adequate naming of the formerly so-called ‘hysteria' [1,2]. Actually, terms, such as ‘conversion’, ‘somatoform’, ‘medically unexplained’, ‘psychogenic’, ‘dissociation’, ‘somatoform’ and ‘functional disorders’ have been concurrently and successively used over the past decades [3]. More recently, a consensus has emerged to promote the use of 'functional neurological disorder' in medical publications, leading to the foundation of the FND Society in 2018 [4]. However, since the beginning of the 2010s, the use of 'functional (psychogenic) neurological disorder' (‘psychogenic’ being put into brackets after ‘functional’) appeared consistently in titles, keywords or abstracts of articles, with a growing frequency, although no consensus or recommendation for using this labelling have been found by the authors. By conducting a bibliographic research in medical and scientific online database (MEDLINE PubMed – end 2022), we found a total of 145 occurrences of ‘functional [psychogenic]’ (F[P]) associated terms since 1960, either in the title of the reference, within the abstract or as keyword (details in the Supplementary Material). First occurrence of the association ‘functional psychogenic’ were retrieved in the English translation from Russian [5] and Romanian [6] articles titles in 1978, respectively, on ‘functional psychogenic disorders of the cardiovascular system’ and ‘functional psychogenic dysphonia’. However, these titles did not use brackets for the term ‘psychogenic’. Seven occurrences from the 145 were not real parenthetical brackets (as in ‘functional (psychogenic)’) but forward slashes (‘functional/psychogenic’), thus suggesting a kind of equivalence between ‘functional’ and ‘psychogenic’, which seems different from what is suggested by using brackets as we will discuss below. The very first occurrence of brackets F(P) was identified in 1987, occurring in the abstract of a paper on pain [7] and the translated title from a German article on F(P) causes of vertigo [8]. Occurrence of brackets F(P) was then retrieved in the English abstract of an Hungarian paper on ‘functional (psychogenic) syndromes’ in 1998, and in the translation of a Spanish title in 2005 on movement disorders of functional origin (psychogenic) in children. However, since 2012, a sudden rise in F(P) utilization was noticed with rapid plateauing. In details, F(P) was mostly used to qualified ‘F(P) movement disorders’ and ‘F(P) seizures’ but many other clinical terms were also involved (Table 1). The fact that the first use of F(P) occurred in the late 1980s, predating FNDS foundation and FND consensus, suggests that the brackets were not used to remind an abandoned term as, for example, in ‘functional (formerly psychogenic)’. Actually, as we have shown in our bibliographic research, the parenthetical ‘(psychogenic)’ has been used for several decades, with a certain upsurge in recent years. In our opinion, putting the word ‘psychogenic’ into brackets in ‘functional (psychogenic)’ suggests that it bears some precision to ‘functional’, given that information placed in parentheses usually provides the reader with additional information about the preceding statement or term. Thus, it seems logical that ‘psychogenic’ may constitute a clarification, adding some precisions to ‘functional’. On the other hand, the parenthetical use of ‘psychogenic’ might also constitute a kind of explanation of the latter term, especially regarding the several and still debated pathophysiological mechanisms proposed for FND. In this logical sense, the use of ‘psychogenic’, as a precision term, would imply the existence of either functional ‘psychogenic’ or ‘non-psychogenic’ neurological disorders, which is clearly misleading. In the last years, ‘functional’ has gained popularity among neurologists as a better and less offensive alternative for naming FND. Yet, if the term ‘functional’ is considered an alternative of ‘psychogenic’, then should the latter be applied as a precision of the former? Conversely, if ‘psychogenic’ is thought to be more precise than ‘functional’, why should it not completely replace it? It seems that even though both terms are equivalent in scope (as to the treated condition), they remain complementary regarding the information conveyed to the medical community as well as to the patient.Table 1. Number of occurrence of ‘functional (psychogenic)’ terms in the medical literature (referenced in PubMed).TermsnFunctional (psychogenic) movement disorders28Functional (psychogenic) seizures18Functional (psychogenic) dystonia7Functional (psychogenic) tremor7Functional (psychogenic) motor symptoms6Functional (psychogenic) gait disorders5Functional (psychogenic) neurological symptoms4Functional (psychogenic) parkinsonism3Functional (psychogenic) symptoms2Functional (psychogenic) form of dizziness2Only those occurring two or more times are depicted.Nevertheless, in our opinion the use of ‘psychogenic’ into brackets should be avoided as it might be confusing and suggestive of a pathophysiological mechanism that the use of ‘functional’ essentially tries to deflect. Moreover, although the stand-alone use of each term is possible and remains the choice of each author and physician, we believe that due to its neutrality and general acceptance, ‘functional’ should be promoted as the reference adjective in functional neurological disorders.Financial disclosureThe authors have no financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.Competing interests disclosureThe authors have no competing interests or relevant affiliations with any organization or entity with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.Writing disclosureNo writing assistance was utilized in the production of this manuscript.Open accessThis work is licensed under the Attribution-NonCommercial-NoDerivatives 4.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/4.0/References1. Loewenberger A, Davies K, Agrawal N, Poole N, Cope SR. What do patients prefer their functional seizures to be called, and what are their experiences of diagnosis? - A mixed methods investigation. Epilepsy Behav. 117, 107817 (2021).Crossref, Google Scholar2. Asadi-Pooya AA, Brigo F, Mildon B, Nicholson TR. Terminology for psychogenic nonepileptic seizures: making the case for ‘functional seizures’. Epilepsy Behav. 104(Pt A), 106895 (2020).Crossref, Google Scholar3. Bratanov C, Hot P, Vercueil L. 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Untersuchung des vestibulo-spinalen Reflexes zur Differenzierung zwischen organischer und funktioneller (psychogener) Ursache des Schwindels [Vestibulospinal reflexes in differentiating between organic and functional (psychogenic) causes of vertigo]. HNO 35(3), 128–135 (1987).CAS, Google ScholarFiguresReferencesRelatedDetails Ahead of Print STAY CONNECTED Metrics History Received 29 December 2022 Accepted 16 May 2023 Published online 2 November 2023 Information© 2023 The AuthorsKeywordsfunctional neurological disorderpsychogenicFinancial disclosureThe authors have no financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.Competing interests disclosureThe authors have no competing interests or relevant affiliations with any organization or entity with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.Writing disclosureNo writing assistance was utilized in the production of this manuscript.Open accessThis work is licensed under the Attribution-NonCommercial-NoDerivatives 4.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/4.0/PDF download