fnd: what is functional neurological disorder?

functional neurological disorder is the second most common reason people need to see a neurologist, after headaches, according to alberta health services, one of the few places in the country that offer an fnd program.

by dave yasvinski

published apr 13, 2023

last updated apr 14, 2023

4 minute read

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4 minute read

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since fnd exists between psychiatry and neurology, it has been understudied and its causes remain largely unknown. getty

functional neurological disorder (fnd) is an umbrella term used to encapsulate complex medical conditions in which there is an issue with the way the nervous system operates and how the brain and body send and receive signals. the issue is functional in nature, meaning it affects the “software” of the nervous system as opposed to other conditions that can affect the “hardware,” such as the damage caused by a stroke. symptoms of the disorder, according to fnd together, manifest in physical, sensory or cognitive ways that have no underlying structural cause and do not fall under any other currently recognized condition or disease. because the disorder exists in the grey area between psychiatry and neurology, it has been understudied and its causes remain largely unknown.

fnd can be triggered by traumatic events

the disorder, which can be triggered by traumatic or stressful events, has gained attention recently because some patients have experienced symptoms following vaccination against covid-19. according to a canadian study, however, these symptoms are not an adverse reaction to vaccines themselves, but manifestations of fnd that have been triggered by the stress of the pandemic and the need for vaccination. the condition has also been known to occur in people who have had nothing more done than a blood test or suffered from a minor wrist sprain.

a common misconception of fnd is that patients are in control of their own symptoms. this is not the case — at least not in any conscious way. the symptoms of fnd are very real and can appear suddenly, progress rapidly and disappear just as quickly. it is the second most common reason people need to see a neurologist, after headaches, according to alberta health services, one of the few places in the country that offer an fnd program. the program, located at south health campus in calgary, helps patients understand and overcome the physical and psychological issues related to the disorder.

it is thought that a multitude of factors predispose a particular individual toward fnd and that these same factors can trigger and exacerbate the condition. because the disorder is so elusive and hard to identify, the simple act of diagnosing a patient and educating them on fnd is the most effective treatment and often the only one required.

symptoms of fnd

the signs of fnd can vary from patient to patient and even change over time within the same patient. these diverse symptoms can include:

movement disorders, such as trouble walking or tremors
dissociative seizures (non-epileptic)
cognitive, memory or sensory changes or dysfunction
dizziness, weakness or paralysis

diagnosing fnd

determining the presence of fnd can be a long, frustrating process because of the wide range of potential symptoms and the absence of tests that determine its presence. as there is nothing wrong with the hardware of the brain or the nervous system, imaging scans will not reveal anything telling. they may be prescribed anyway, if only to eliminate the likelihood of other neurological disorders. on average, it takes around seven years from the onset of symptoms for patients to receive a correct diagnosis.

for this diagnosis, the canadian study says neurological symptoms “need to be incongruent with recognized neurological or medical disease, not better explained by another condition and result in significant functional impairment.”

despite the increased attention the disorder has received since the start of the pandemic, the study concluded that “no evidence exists to suggest a direct causal relationship between specific constituents in the sars-cov-2 vaccine and fnd; patients may develop fnd after vaccination owing to a variety of complex and incompletely understood factors.”

treating fnd

addressing the symptoms of fnd primarily involves informing patients of their diagnosis and helping them to better understand the disorder. sometimes, simply putting a name to the things they have been experiencing and reassuring them that there are no serious underlying issues are all the treatment they need.

in other cases, a multidisciplinary (or collaborative) approach that incorporates an individual patient’s biological, psychosocial and social circumstances has generally been found to produce the best results. this can involve physiotherapy (to retrain the body to move properly), psychological or cognitive behavioural therapy (to reduce the severity of symptoms) and medication. while there are no drugs currently approved for the treatment of fnd, medications that address depression, fatigue and anxiety have proven helpful for some patients.

preventing fnd

it is difficult to prevent an encounter with fnd because so little is known about it. for those who have received a diagnosis, a better understanding of disorder and the individual triggers that can cause it to occur may help send the disorder into remission.

prevalence of fnd

according to the journal of psychiatry and neuroscience, fnd occurs in around 4-12 out of every 100,000 people, a prevalence similar to multiple sclerosis and amyotrophic lateral sclerosis.

support for fnd

for more news and information about fnd or to find peer-to-peer support for the disorder, visit fnd together. fnd awareness day is on april 13.

dave yasvinski is a writer with  healthing.ca.

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dave yasvinski

fnd: what is functional neurological disorder?