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Functional neurological disorder

The term functional neurological disorder encompasses a wide range of symptoms that are often very debilitating. Doctors tend to categorise these symptoms according to their medical frame of reference, but often fail. Functional neurological disorders have no formal way of being diagnosed by doctors. They can, however, be treated.

At a glance

  • Functional neurological disorders (FND) cause physical symptoms not explained by other conditions.

  • Common symptoms include tingling, tremors, headaches, vision changes, and difficulty with memory.

  • The symptoms are not faked and all medical tests are usually normal.

  • Treatments focus on managing symptoms, using therapies like physiotherapy or psychotherapy.

  • Medications are generally not recommended for FND symptoms.

  • Understanding your condition and joining support groups can help you manage symptoms.

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What are functional neurological disorders?

The medical world has made some great advances in the last thirty years or so. But in recent times it has become apparent that there are a lot of symptoms out there that doctors just can't put their finger on.

When someone has problems or symptoms that don't fit into a specific diagnosis or can't be shown on a blood test or scan, doctors often use the term 'functional'. Some patients don't like this term because it can sound like they're being dismissed; however, other patients find it helpful to be given some sort of label. Patients who have been told they have functional disorders have begun to form groups to help understand their problems: this is very helpful as they can compare symptoms and help each other become aware of treatments.

Common symptoms that are experienced by people with a functional neurological disorder include:

  • Tingling in the hands or feet.

  • A tremor in one or both arms.

  • Headaches or migraines.

  • Changes in eyesight, like blurred vision or seeing flashing lights.

  • Difficulty with memory or doing complicated tasks.

  • Problems sleeping, including sleeping too much or too little.

  • Changes to personality, like becoming more irritable or depressed.

  • Seizures or shaking of the body.

  • Pain in the arms or the legs that cannot be controlled by normal painkillers.

  • Problems with the bowels and the bladder, like passing water more than usual or having difficulty moving one's bowels.

  • Sudden fainting or loss of consciousness.

  • An inability to move an arm or a leg properly, or a heavy feeling down one side of the body.

  • Problems concentrating.

Specialists have found two broad sub-types that are the most common - motor problems and seizures.

The difficulty is many of these symptoms are present in other neurological conditions like Parkinson's disease, multiple sclerosis and epilepsy. That is why a doctor will usually rule out these conditions before considering a functional neurological disorder.

This is an area of contention because doctors can't find a definite 'cause': all blood tests, scans, and other investigations are normal. But the person certainly isn't 'making it all up': they are not malingering or faking.

One theory is that the brain, although wired up OK, doesn't control movements or receive sensations normally: hence the unusual movements like tremors, and the abnormal feelings like tingling or pain.

Many people who do not have functional neurological disorders themselves often attribute the person's symptoms to stress or emotional problems. This is valid in some cases but may be over-simplifying things. Many people with functional symptoms have had an emotional or psychological trauma in the lead-up to them developing symptoms, but others haven't. Sometimes two things coincide: a physical illness like the flu or a bad viral illness, coupled with a recent emotional trauma.

This is therefore an area where modern medicine, despite its many advances, cannot fully explain something that affects a large number of people. Another difficulty with talking about 'causes' is that the language used (with words like 'psychological', 'stress' and 'trauma') is often interpreted differently by different people.

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Doctors from almost every specialty will be familiar with patients whose symptoms do not fit a specific diagnosis or a 'box'. It is hard to quantify exactly how many people in society experience these symptoms, because many may not consult a doctor.

What is known for certain is that the symptoms are debilitating: people with functional neurological disorders rate their condition as just as devastating as people with Parkinson's disease, for example. And most family doctors, or GPs, will know how these problems can often severely affect a person's ability to live a normal life.

Most people with functional neurological disorders find that medications do not help. It is tempting to take medications and, indeed, it is tempting for doctors to prescribe them, but each medicine carries its own set of side-effects.

Treatments generally consist of managing the symptoms and finding a way of living with them and understanding them.

Rehabilitation with physiotherapy or occupational therapy has been shown to be helpful for the more 'movement' side of functional neurological disorders, like weakness or tremors.

For the more 'sensory' type of symptoms like pain and seizures, psychotherapy and cognitive behavioural therapy can help.

In general, doctors who work in the field and patient support groups do not recommend medications for the symptoms of functional neurological disorders. An example is painkillers: many patients end up on huge quantities of pain relief which hardly ever helps; each painkiller has side-effects too and is often addictive.

Unfortunately, because conventional NHS doctors often can't help a great deal, there are a lot of practitioners with dubious qualifications out there. They often promise great cures, at vast expense. Vulnerable patients can then end up spending huge sums of money on an unattainable goal. Please be careful: try to find a reputable doctor who works in the field in a state-funded system (like the NHS) or who is covered by your insurance.

In general, the more you understand and know about functional neurological disorders, the better you can manage your symptoms. Try to find a local self-help group and meet others with the condition to find out what works for them.

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Thankfully functional disorders are now being taken more seriously by the medical world than ever before. It may be that a classification system will be set up to categorise different types of the condition. That way, treatments can be tested in trials and more can be learnt about the condition.

Frequently asked questions

Why do doctors use the term 'functional' if some patients dislike it?

Doctors use the term 'functional' when symptoms don't fit a specific diagnosis or can't be shown on blood tests or scans. While some patients may feel dismissed by the term, others find receiving a label helpful for understanding their condition and connecting with support groups.

How do doctors differentiate functional neurological disorders from conditions like Parkinson's or Multiple Sclerosis?

Many symptoms of functional neurological disorders are similar to those found in other conditions like Parkinson's disease, multiple sclerosis, and epilepsy. Because of this overlap, a doctor will typically rule out these other neurological conditions through various investigations before identifying a functional neurological disorder.

What is the medical community's current understanding of what causes these disorders?

The definite cause of functional neurological disorders is not yet clear, as all blood tests, scans, and investigations appear normal. One theory suggests that the brain, despite being structurally sound, doesn't control movements or receive sensations as it should. While some cases are linked to prior emotional or psychological trauma, this isn't always the case, and sometimes a physical illness combined with trauma can coincide before symptom onset.

If medications aren't generally recommended, what are the primary approaches to treatment?

Treatment for functional neurological disorders primarily focuses on managing symptoms and helping people understand and live with their condition. Rehabilitation therapies like physiotherapy and occupational therapy are helpful for movement-related issues, such as weakness or tremors. For sensory symptoms like pain and seizures, psychotherapy and cognitive behavioural therapy can be beneficial. It's noted that medications, including painkillers, often don't provide significant help and carry risks of side-effects or addiction.

How can I find reliable help and avoid unproven treatments for functional neurological disorders?

Since conventional treatments may not always be effective, it's important to be cautious of practitioners offering expensive cures with dubious qualifications. The article advises seeking a reputable doctor who works within a state-funded healthcare system (like the NHS) or is covered by insurance. Understanding and learning about functional neurological disorders, and finding local self-help groups, can also be very beneficial.

Further reading and references

  • Rommelfanger KS, Factor SA, LaRoche S, et al; Disentangling Stigma from Functional Neurological Disorders: Conference Report and Roadmap for the Future. Front Neurol. 2017 Mar 29;8:106. doi: 10.3389/fneur.2017.00106. eCollection 2017.
  • Bennett K, Diamond C, Hoeritzauer I, et al; A practical review of functional neurological disorder (FND) for the general physician. Clin Med (Lond). 2021 Jan;21(1):28-36. doi: 10.7861/clinmed.2020-0987.
  • Popkirov S, Nicholson TR, Bloem BR, et al; Hiding in Plain Sight: Functional Neurological Disorders in the News. J Neuropsychiatry Clin Neurosci. 2019 Fall;31(4):361-367. doi: 10.1176/appi.neuropsych.19010025. Epub 2019 May 23.
  • Aybek S, Perez DL; Diagnosis and management of functional neurological disorder. BMJ. 2022 Jan 24;376:o64. doi: 10.1136/bmj.o64.

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About the authorView full bio

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Dr Oliver Starr, MRCGP

MBChB, BMedSc, MRCS, MRCGP, DRCOG

Dr Oliver Starr is a general practitioner in Hertfordshire and an undergraduate tutor at University College Medical School.

About the reviewerView full bio

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Dr Toni Hazell, MRCGP

MBBS, BSc, MRCGP, DFSRH, Dip GU med, DRCOG, DCH (London, UK, 2000)

Dr. Toni Hazell qualified from St. Mary’s Hospital Medical School and did her VTS at Northwick Park Hospital.

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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