What is Functional Neurological Disorder
Functional Neurological Disorder (FND) is a condition that affects the way the brain and nervous system work, leading to a range of neurological symptoms such as limb weakness, paralysis, seizures, walking difficulties, spasms, sensory issues, cognitive problems and more.
Anyone, at any age, can be diagnosed with FND. For many, the symptoms are severe, disabling, and life-changing.
Whilst the symptoms of FND may resemble those of other neurological conditions, such as Multiple Sclerosis, Parkinson’s Disease, and Epilepsy, the underlying cause of FND is different. Unlike these conditions, which involve structural damage or disease in the nervous system, FND is a result of how the brain and nervous system are functioning.
The basic “wiring” of the nervous system remains intact, but the brain may struggle to send and receive signals correctly. This can affect how the body performs tasks like controlling movement and focusing attention.
“Functional Neurological Disorder is often explained to patients as a psychological reaction due to past trauma, or as symptoms due to stress. These explanations often fail, leaving patients feeling alienated, stigmatized, and not believed. The reason for this failure is that these explanations turn a potential risk factor into the cause of the problem.”
– Cock HR, Edwards MJ (2018) Read the full reference here
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A diagnosis of FND should be made by a neurologist based on positive neurological signs and specific tests. For example, Hoover’s Sign is a test that can help diagnose limb weakness associated with FND.
Accurate diagnosis is essential to avoid misdiagnosis, as FND can sometimes present alongside other neurological conditions. It’s important to consider that FND may co-exist with other conditions, so comprehensive assessment is crucial.
Throughout history, a lack of understanding of FND has led to people being dismissed, neglected or not believed. To this day this is still happening across the UK, and below are some FND myths sourced from the consensus paper A practical review of functional neurological disorder (FND) for the general physician, written by some of the leading specialists in the field.
The diagnosis of FND should be ‘ruled in’ based on the presence of positive signs.
FND commonly co-occurs with other neurological conditions.
A bizarre presentation does not equate to a diagnosis of FND. Unusual presentations can occur with other neurological conditions.
Shared mechanisms and comorbidities, such as pain and fatigue, may be present between patients with FND.
FND symptoms are involuntary. Patients are not ‘putting them on’ as have no form of control. Feigning is very rare.
Investigations can be useful to identify comorbid neurological conditions. Other neurological conditions are a strong risk factor for FND.
FND is not misdiagnosed more than other conditions. Erroneously diagnosing FND as another neurological condition can be as harmful as the reverse.
Psychological factors are one of many possible risk factors for FND and should not be considered the sole aetiological cause.
Patients with FND are as disabled, and have as impaired quality of life, as patients with other neurological conditions.
FND treatment is individualised and multidisciplinary, involving combinations of physical and psychological rehabilitation.
Further reading: Lidstone SC, Araújo R, Stone J, Bloem BR. Ten myths about functional neurological disorder. Eur J Neurol. 2020 Nov;27(11):e62-e64. doi: 10.1111/ene.14310. Epub 2020 Jun 4. PMID: 32400011.
Although symptoms of FND are commonly seen in neurology, epilepsy, and paediatric clinics, the exact cause remains unclear. Research suggests that symptoms arise from a problem in how the brain functions – particularly how it processes and sends signals to the body – rather than from structural damage. For some people, FND may follow illness, injury, or psychological stress, but for many, symptoms appear without a clear trigger.
While standard brain scans are often normal, this doesn’t mean nothing is happening. Advanced imaging, such as functional MRI (fMRI), has started to reveal differences in brain network activity in people with FND. These findings reflect the complexity of the brain–body relationship and underscore the need to understand health through a biopsychosocial lens – not just in FND, but across all areas of medicine. As research continues, it’s helping to build a fuller picture of how symptoms develop and how recovery might be supported.
To learn more about Functional Neurological Disorder, we recommend visiting the neurosymptoms website, a key medical resource managed by a leading expert in the field. This site offers valuable insights into understanding FND and is widely used by healthcare professionals.
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