Comment on Psychogenic Versus Functional Movement Disorders We read with great interest the recent viewpoints of Drs. Edwards, Stone, and Lang and Drs. Fahn and Olanow on appropriate terminology of psychogenic versus functional movement disorders.1,2 Obviously what they write carries a lot of weight and hence it is important to enter this debate, as we do think that different opinions need also to be voiced. We understand that the use of the term psychogenic in movement disorders has been indeed critical for the distinction of different conditions, particularly dystonia, in the era in which knowledge about phenomenology and pathophysiology was fragmented, and clear terminological division was necessary to prevent misdiagnoses. However, we do believe it is difficult to reconcile the contemporary use of this term with advances in basic neuroscientific and clinical knowledge. Despite being loosely defined,3 the term psychogenic in movement disorders refers to a presumed causal relation between psycho(patho)logical factors and the generation of abnormal movements. However, the psychopathological profiles of patients with psychogenic/functional movement disorders are broadly similar to those of patients with organic movement disorders or healthy controls.4 It is inherently paradoxical for neurologists to label patients as psychogenic without though being able to diagnose psychogenicity and/or even more explain its role in generation of symptoms, and thus, deferring responsibility to a different discipline. In fact, even if neurologists were convinced of doing so, the called-upon psychiatry experts would not use psychogenicity as a prerequisite for diagnosing conversion disorder (or functional neurological symptom disorder) according to the criteria of the latest Diagnostic and Statistical Manual of Mental Disorders version.5 Also, as previously highlighted, the term psychogenic propagates the dualistic distinction of the mind from the brain.1 This conceptual dichotomy creates confusion and disciplinary division, rather than the much-needed synergy of expertise across neurologists, psychiatrists, psychologists, and rehabilitation specialists to treat patients with such disorders. We agree that the term functional is not optimal and merits greater precision in its application.6 Indeed, most contem-
porary clinical literature, including our own, uses the terms functional and psychogenic interchangeably. We also recognize that the application of either of the two terms may differ between languages. However, the use of the term functional to define a syndrome without etiological inferences but taking into account different factors, including physical contributors7 and signs,8 is, we believe, a more scientific approach and stimulates a true bio-psycho-social approach to research.1 It also leaves space for the much-needed patient acceptance9 and thus leads the way for improved engagement with treatment. Christos Ganos, MD,1,2 Roberto Erro, MD,1 Kailash P. Bhatia, MD,1 and Michele Tinazzi, MD3 1 Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, University College London, London, United Kingdom 2 Department of Neurology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany 3 Department of Neurological and Movement Sciences, University of Verona, Verona, Italy
Edwards MJ, Stone J, Lang AE. From psychogenic movement disorder to functional movement disorder: it’s time to change the name. Mov Disord 2014;29:849-852.
Fahn S, Olanow CW. “Psychogenic movement disorders”: they are what they are. Mov Disord 2014;29:853-856.
Lewis A. ’Psychogenic’: a word and its mutations. Psychol Med 1972;2:209-215.
Kranick S, Ekanayake V, Martinez V, Ameli R, Hallett M, Voon V. Psychopathology and psychogenic movement disorders. Mov Disord 2011;26:1844-1850.
American Psychiatric Association. Diagnostic and statistical manual of mental health disorders: DSM-5. 5th ed. Washington, DC: American Psychiatric Publishing, 2013.
Pritchard EA. The functional symptoms of organic disease of the brain. Lancet 1955;268:363-366.
Parees I, Kojovic M, Pires C, et al. Physical precipitating factors in functional movement disorders. J Neurol Sci 2014;338:174-177.
Stone J, Edwards M. Trick or treat? Showing patients with functional (psychogenic) motor symptoms their physical signs. Neurology 2012;79:282-284.
Stone J, Wojcik W, Durrance D, et al. What should we say to patients with symptoms unexplained by disease? The "number needed to offend." BMJ 2002;325:1449-1450.
-----------------------------------------------------------*Correspondence to: Dr. Christos Ganos, Clinical Movement Disorders Group, Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, University College London, London, United Kingdom, E-mail: [email protected]
Relevant conflicts of interest/financial disclosures: Nothing to report. Full financial disclosures and author roles may be found in the online version of this article. Received: 21 June 2014; Accepted: 24 August 2014 Published online 24 September 2014 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/mds.26038
Movement Disorders, Vol. 29, No. 13, 2014
Functional/Psychogenic Movement Disorders: Do We Know What They Are? Fahn and Olanow’s viewpoint article1 in response to our original paper2 argues for the retention of the term psychogenic on the basis, among other points, that “they are what they are.”