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Semin Neurol
DOI: 10.1055/a-2753-9066
Review Article

The Dawn of Functional Neurologic Disorder

Authors

  • Mary A. O'Neal

    1   Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States

  • Barbara Dworetzky 

    2   Department of Neurology Mass General Brigham, Harvard Medical School, Boston, Massachusetts, United States
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Introduction

There has been a renaissance in the understanding of Functional Neurological Disorder (FND). This is reflected by the increasing interest of clinicians and scientists in this common and disabling disorder, reflected in part by the successful establishment of the International Functional Neurological Disorder Society in 2018, the society's steadily increasing membership, and the rise of publications on the disorder, including this volume of Seminars in Neurology. The FND society emerged from interested clinicians and scientists meeting to discuss these patients who were not being adequately helped by the medical system, and despite how commonly they are seen (see the paper on epidemiology by Gilmour et al), are underfunded by research programs. Mark Hallett almost two decades ago recognized this as “a crisis for neurology” and helped provide support through his work with the Movement Disorder Society (now called the International Parkinson and Movement Disorder Society), to bring the disorder out of a neglected state and to work toward understanding the neurophysiological mechanisms and subtypes of the disorder to begin to help the multitude of patients seen in our clinics and wards across the world in order to provide up to date education on management so that clinicians seeing these patients know how to help and not harm people living with the disorder.[1] [2] Along with esteemed colleagues all over the world, but especially Jon Stone and Alan Carson in Edinburgh, FND is now becoming a recognized neurological disorder with some evidence-based treatments and has become a growing area for fruitful research.

The original name for FND was Hysteria. The definition of hysteria dates back to ancient Greek medicine, where it was described as a disorder of females and thought to arise from disturbances or movement of the uterus. The idea was that affected females had a wandering uterus moving throughout the body, which produced a variety of physical and psychological symptoms.[3] Boylan et al have written in this issue about female predominant disorders and risks for FND. It was Jean-Martin Charcot, considered to be the founder of modern Neurology, who brought a spotlight to the disorder among his many other accomplishments in neurology. As chief of the Salpêtrière Hospital in Paris in the late 19th century, he took a great interest in studying patients in their asylum to better understand the brain mechanisms of hysteria. He introduced the concept of “dynamic lesions,” suggesting that hysteria was due to changes in brain function rather than structural pathology.[4] He also pioneered the use of hypnosis as both a diagnostic and therapeutic tool.[5]

In the 20th century, Freud introduced the concept of “conversion” to describe what he believed was at the root of what he was observing: a process by which unconscious psychological conflict was transformed into physical symptoms. The transition to the term conversion led to a shift from a neurological to a psychiatric framework to understand the disorder.[6] During World War I, it became clear that men too suffered from a similar disorder, and the original term “shell shock” was changed to “battle fatigue.”[7] However, this approach of emphasizing psychological mechanisms over time has led to increased stigma and diagnostic uncertainty, with neurologists perhaps feeling absolved of the need to help manage the disorder along with psychiatrists.[8] This contributed to patients feeling blamed for their symptoms and not obtaining medical support, as both psychiatrists and patients continued to feel that neurologists should help them. In addition, the multitude of different names used for the disorder over the centuries and across the globe has added to the confusion and was a large driver to move to a single name acceptable for patients to engage in available treatments to try to help them improve as early as possible after diagnosis, rather than to continue their search for someone who might be knowledgeable or confident in what is ailing them.



Publication History

Received: 29 September 2025

Accepted: 11 November 2025

Article published online:
03 December 2025

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