functional neurological disorder: what to know about causes, symptoms and treatments
fnd is linked to how the brain functions, affecting the nervous system and impacting body functions, speech, movement, memory and concentration.
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common problems of fnd are episodes of altered or loss of consciousness called dissociative attacks. these episodes often look like fainting or epileptic seizures.
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functional neurological disorder (fnd) is a neurological condition where the brain’s communication system is disrupted, causing symptoms that look like signs of parkinson’s disease, multiple sclerosis or stroke—but there’s a different problem at work. while degenerative disorders like parkinson’s damage brain structure, fnd is linked to how the brain functions, affecting the nervous system and impacting body functions, speech, movement, memory and concentration.
a simple way to explain what is recognized as a group of debilitating fnds is to think of your brain as a computer. for someone living with fnd, the hardware or cables are in working order but the software has numerous glitches.
the incidence of fnd in the general population is comparable to the prevalence of multiple sclerosis in canada, which is estimated at 290 out of every 100,000 canadians. one patient describes fnd as “the most common disorder you’ve never heard of.” dr. anne-marie abe, a neuropsychiatrist specializing in functional neurological disorders in ottawa, ont. notes that fnd is the second most common reason for referral to outpatient neurology clinics and presents in up to 30 per cent of people with a diagnosed neurological disorder that is followed by outpatient neurology.
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functional seizures make up 10 to 26.5 per cent of all seizures seen in the emergency department, where there’s a lack of concrete emergency treatment options for fnd and a knowledge gap of emergency physicians relating to fnd.
unfortunately, patients living with fnd say they’ve been stigmatized by the medical system. in a patient survey by the fnd hope organization for research and advocacy around fnd, 82 per cent of patient respondents indicated they had been treated poorly because of stigma relating to their fnd diagnosis, primarily by emergency physicians.
what causes functional neurological disorder?
fnd has no known cause or predisposing factor. older ideas that fnd is “all psychological” and therefore always associated with stress or past trauma have changed since the mid-2000s, according to the national organization for rare disorders. the new understanding, including modern neuroscientific studies, has shown that fnd is a disorder of the nervous system with specific clinical features of its own. it can affect anyone, at any time, although it is uncommon in children under 10. it is about two to three times more likely to affect females than males for most symptoms, although it occurs equally in both groups for people over 50. most people with fnd start to have symptoms around their late 30s, and symptoms of functional seizures most often begin in a person’s late 20s.
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more recent theories suggest that fnd has many causes, which vary from person to person, much like heart disease that can be linked to smoking, genetic factors, diet and depression. for some people with fnd, psychological factors like past trauma or stress at the time of symptom onset are key to understanding how the brain has gone wrong. in others, migraine or a physical injury may be the most important contributor.
symptoms of functional neurological disorder
common problems of fnd are episodes of altered or loss of consciousness called dissociative attacks. these episodes often look like fainting or epileptic seizures, but there’s no misfiring of electrical activity in the brain that happens with epilepsy.
signs of fnd can also include the following:
- difficulty walking
- tremors
- numbness like the sensation of pins and needles
- limb weakness or even full-body paralysis
- speech disturbance
- cognitive and sensory issues
- digestive issues
- extreme fatigue
- chronic pain
essentially, every function that is controlled by the brain can be affected. some experts describe fnd symptoms as nervous system symptoms that can’t be explained by a neurological disease or other medical condition. these involuntary symptoms can appear suddenly, increase with attention to them, and decrease when the person is distracted. some symptoms last for years.
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diagnosis and treatment of functional neurological disorder
conventional tests such as mri brain scans and eegs are usually normal in people with fnd. however, research studies that have used functional neuroimaging and neurophysiology —which focus on how the brain works rather than what it looks like—have shown changes in the connections between different areas of the brain. in fnd, the brain is unable to send and receive signals properly, so patients often have trouble controlling their actions. there’s also research that reveals increased activity in the limbic system, which deals with emotions and behaviours, leading to difficulty regulating emotion and responding to stress.
not surprisingly, fnd can be difficult to understand for the person with the disorder, their family and friends, and their healthcare team. physicians can attribute symptoms to other disorders, and adding to the complexity, fnd can co-exist with other illnesses like stroke and epilepsy. the healthcare team will look for specific triggers and patterns of symptoms to help make a diagnosis, and a neurologist is typically required to assess which symptoms relate to fnd and to monitor where required for any new symptoms
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as with many disorders, early diagnosis and treatment can help lessen symptoms and promote healing.
as noted expert in the field, dr. jon stone, told bmj, “treatment depends on helping people understand their condition and using rehabilitation therapies like physiotherapy and psychological therapy.” communication between the healthcare provider and the patient is foundational for the patient to actively participate in their own treatment and improve outcomes. a healthcare team of various specialties ideally work together with the individual to develop a treatment plan of physical therapy and psychotherapy.
medications may help with certain symptoms including anxiety, depression, insomnia and headache that may happen with fnd. patients with functional seizures, however, should not take epileptic anti-seizure medications which could make symptoms worse. it helps to identify warning signs and learn techniques to avoid injury during and after the seizure.
other therapies are also showing promise for fnd, including transcranial magnetic stimulation (tms), where magnetic fields generated outside the skull stimulate nerve cells in the brain. and transcutaneous electrical stimulation (tens), which uses low-voltage noninvasive electrical current to activate nerves, can help with pain relief in some patients.
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as stone remarked to bmj about fnd patient successes, “when i help people get their seizures under control, see them walk again, or sometimes even help blind patients see again, it feels pretty amazing.”
international fnd awareness day is celebrated on april 13, 2025. to learn more about the ongoing awareness efforts, visit fnd hope.
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