What is Functional Neurological Disorder (FND) and How Is It Diagnosed in the UK?

Functional Neurological Disorder (FND) is a genuine neurological condition that affects the way the brain and nervous system function. No it isn't someone putting it on.

FND can cause a wide range of symptoms, including problems with movement, sensation, speech, awareness, memory and concentration. Symptoms can be extremely disabling and may fluctuate over time.

Despite this, FND is still not well understood by everyone, including some healthcare professionals. This can make getting a diagnosis and finding appropriate support a difficult experience.

Our Surrey FND support group is working with FND Action, a UK charity dedicated to supporting people affected by Functional Neurological Disorder, to help raise awareness and provide a local community for people with FND, their families and carers.

What exactly is FND?

The word functional can sometimes be confusing.

In FND, the problem is with how the nervous system is functioning, rather than there necessarily being visible structural damage to the brain or nervous system.

One way of thinking about it is that the brain's "hardware" may look normal on conventional scans, but there is a problem with how the brain's networks are processing and communicating information.

FND is therefore a neurological disorder, not simply a psychological condition.

Research into FND is continuing to improve our understanding of how different brain networks involved in movement, sensation, attention and awareness can become disrupted.

Importantly, FND symptoms are real and involuntary. People with FND are not consciously producing their symptoms or simply "making them happen".

FND Action describes FND as a problem with how the brain and nervous system send and receive information.

What symptoms can FND cause?

FND can affect people in very different ways. Some people have one main symptom, while others experience several different symptoms.

Possible symptoms include:

• Limb weakness or paralysis

• Difficulty walking or changes in walking pattern

• Tremor or shaking

• Muscle spasms or abnormal movements

• Functional dystonia

• Functional seizures

• Numbness or altered sensation

• Changes in vision

• Speech difficulties

• Problems with swallowing

• Dizziness or balance problems

• Problems with memory and concentration

• Fatigue

• Pain

• Altered awareness

Symptoms can fluctuate. Someone may be able to perform an activity relatively normally at one time but have considerable difficulty performing it at another.

FND can also occur alongside other neurological or medical conditions. Having an FND diagnosis does not automatically mean that every symptom a person experiences is caused by FND.

How is FND diagnosed?

One of the most important things to understand about FND is that it should not simply be diagnosed because other tests are normal.

Historically, FND was sometimes described as a "diagnosis of exclusion". Modern understanding is different.

FND is generally diagnosed as a positive neurological diagnosis.

This means that a neurologist looks for particular clinical features or signs during a neurological examination that are characteristic of FND.

For example, in someone experiencing functional leg weakness, a neurologist may use a test known as Hoover's sign. Other clinical tests can be used for symptoms such as tremor or abnormal movements.

For functional seizures, the clinician may look at the characteristics of the episodes and, where appropriate, use investigations such as video-EEG to help distinguish functional seizures from epileptic seizures.

FND Action emphasises that the diagnosis should be based on positive clinical signs rather than simply on the absence of another diagnosis.

What happens when you see your GP?

For someone experiencing neurological symptoms that could potentially be FND, the first step will often be an appointment with their GP.

The GP will normally take a medical history and assess the symptoms. Depending on the circumstances, they may arrange initial investigations or refer the person to a neurologist.

It is important to remember that many neurological conditions can produce similar symptoms. A person with new neurological symptoms therefore needs an appropriate medical assessment rather than trying to diagnose themselves from information on the internet.

What happens at a neurology appointment?

A neurologist will normally take a detailed history and carry out a neurological examination.

They may ask about:

• When the symptoms started

• How the symptoms have changed

• What makes them better or worse

• Previous illnesses or injuries

• Other neurological or medical conditions

• Medication

• Episodes of weakness, movement problems or altered awareness

• The impact symptoms are having on everyday life

The neurological examination is particularly important because the neurologist is looking for positive signs of FND.

Additional investigations may also be appropriate.

These can include blood tests, MRI or CT scans, EEG or other neurological investigations, depending on the symptoms and the differential diagnosis.

These investigations are not necessarily being used to "prove" FND. They may be important for identifying another condition, checking for conditions occurring alongside FND, or resolving diagnostic uncertainty.

Does a normal MRI mean that someone has FND?

No.

A normal MRI does not, by itself, establish a diagnosis of FND.

Many neurological conditions can have normal structural brain imaging, particularly when symptoms are related to how the nervous system functions rather than visible structural damage.

This is why the clinical examination and the identification of positive features are so important.

Similarly, having an abnormal scan does not necessarily rule out FND. Some findings on scans can be incidental, and a person can have FND as well as another neurological condition.

Is FND caused by stress or psychological problems?

This is one of the areas where there are many misconceptions.

Stress, illness, injury, pain, trauma and other factors can be associated with FND in some people. However, there is no requirement for someone to have experienced psychological trauma or significant stress before developing FND.

FND should not be diagnosed simply because someone has anxiety, depression, psychological difficulties or has recently experienced stress.

Similarly, the absence of psychological problems does not rule out FND.

FND Action highlights the importance of avoiding a diagnosis based solely on psychological features or recent stress.

What happens after diagnosis?

Receiving a diagnosis is an important first step, but it should not be the end of the process.

Good communication about the diagnosis is important. People should have an opportunity to understand:

• What FND means

• Why the clinician believes they have FND

• Which clinical signs support the diagnosis

• What treatment and rehabilitation options may be appropriate

• Whether they have other conditions that also need treatment

• Where they can obtain further information and support

Treatment is individual and depends on the person's symptoms and circumstances.

Depending on the problems experienced, support may involve physiotherapy, occupational therapy, speech and language therapy, psychological or neuropsychological support, pain management, fatigue management or other specialist services.

The aim is not simply to tell someone to "live with it". Rehabilitation can focus on improving function and helping people manage symptoms and participate in everyday activities.

NICE's current guidance on rehabilitation for chronic neurological disorders specifically includes FND and recommends personalised rehabilitation and information for people with FND and their families or carers.

What is changing in the UK?

There has been increasing recognition of FND within the NHS.

NHS England's specialised neurology service specification, effective from 1 April 2026, specifically includes Functional Neurological Disorder services.

The specification says that NHS services should provide access to neurologists who can diagnose and explain FND, appropriate investigations when needed, follow-up where clinically indicated, and pathways into rehabilitation and other specialist services. It also describes specialist multidisciplinary FND services for people who need further assessment or treatment.

This represents an important step towards recognising FND as a neurological condition requiring appropriate neurological and rehabilitation services.

However, access to services can still vary between different parts of the UK.

FND and the importance of support

An FND diagnosis can be difficult to understand, particularly if someone has spent a long time looking for an explanation for their symptoms.

It can also be isolating. Friends, family, colleagues and even healthcare professionals may not always understand why symptoms can fluctuate or why someone can sometimes perform an activity but struggle to do it at another time.

This is one reason why local support groups can be valuable.

Being able to talk to other people who understand the practical realities of living with FND can provide reassurance, information and a sense that you are not dealing with the condition alone.

FND Action and our Surrey support group

Our Surrey support group has teamed up with FND Action, a UK charity dedicated to supporting people affected by Functional Neurological Disorder.

FND Action provides information about FND, diagnosis, treatment and support, as well as community groups for people with FND, family members and carers.

There is also an FND Action Surrey Community Group, providing an opportunity for people affected by FND in Surrey to connect with others locally.

The current Surrey group meets at:

Woodhatch Community Centre
Whitebeam Drive
Reigate
RH2 7LS

The group currently meets on the third Thursday of each month, 2pm–4pm.

FND Action also provides UK-wide information and online community support. Details of the Surrey group and other FND Action community groups can be found on the FND Action website.

Where can I find reliable information about FND?

FND is a complicated condition, and information found online is not always accurate or up to date.

We recommend using reliable sources such as:

FND Action – information, support and community groups for people affected by FND.

NICE – national clinical guidance covering rehabilitation for people with FND.

NHS England – information about NHS service specifications and the development of specialist neurological services.

It is also important to remember that information about FND cannot replace an individual medical assessment.

If you have new or unexplained neurological symptoms, speak to your GP or another appropriate healthcare professional.

About our Surrey FND Support Group

Our group exists to provide a friendly and supportive local community for people living with Functional Neurological Disorder, as well as their families and carers.

You do not have to face FND alone.

Whether you have recently been diagnosed, have been living with FND for many years, or are supporting someone with the condition, you're welcome to find out more about our group.

Together with FND Action, we are working to improve understanding of FND and make sure that people affected by FND in Surrey know that support is available.