Functional neurological disorder (FND) explained

Functional neurological disorder, or FND, is a condition where the brain and body are not sending and receiving signals properly. It can cause real and sometimes disabling symptoms, such as weakness, tremor, seizures, numbness and problems with memory and concentration.

Many people with FND have been told their tests are normal and left without a clear explanation. This guide explains what FND is, how it is diagnosed, which treatments can help, and where neuropsychology fits in.

What is functional neurological disorder?

The Australian Institute of Health and Welfare describes FND as a condition that results from improper functioning of the central nervous system, where signals between the brain and different parts of the body are disrupted.

A common way to explain it is to compare the brain to a computer. In many neurological conditions, such as stroke or multiple sclerosis, there is a problem with the hardware, meaning the physical structure of the brain. In FND, the hardware is usually intact, but there is a problem with the software, meaning how the brain is running its programs. As the Brain Foundation puts it, the brain’s structure is usually normal, but its functioning is disrupted.

You may also see older terms such as conversion disorder. Most clinicians now prefer the term FND because it describes the problem without assuming a cause.

How common is FND?

The AIHW estimates that at least 21,500 Australians were living with FND in 2024, and notes that the true number is likely higher. In the 2023 to 2024 financial year there were around 6,100 hospital stays where FND was the main diagnosis, and about three quarters of these were for females. FND can affect people of any age or background.

Common symptoms

FND looks different from person to person, and symptoms can change over time. The AIHW and the Brain Foundation list symptoms including:

• weakness or paralysis of a limb
• tremor, jerks or other abnormal movements
• walking and balance difficulties
• functional or dissociative seizures, which look like epileptic seizures but have a different cause
• numbness or altered sensation
• speech and swallowing problems
• vision problems and dizziness
• fatigue and pain
• thinking problems, often described as brain fog
• bladder and bowel symptoms

An international review in The Lancet Neurology by Hallett and colleagues emphasises that these symptoms are genuinely experienced. People with FND are not imagining or faking their symptoms.

What causes FND?

Researchers are still learning about the causes. The Brain Foundation explains that changes in brain networks involved in movement, attention, emotion and processing sensations may contribute to symptoms.

Hallett and colleagues note that psychological stressors are common risk factors, but are often absent. Other things that can come before FND include a physical injury, an illness, a medical procedure, pain or another neurological condition. Some people with FND also have a condition such as epilepsy or migraine.

This matters because many people with FND have been told their symptoms are all in the mind or caused by stress. That explanation is incomplete and can feel dismissive. Hallett and colleagues describe FND as a disorder at the meeting point of neurology and psychiatry, where brain, body and mind all play a part.

How FND is diagnosed

FND is usually diagnosed by a neurologist. A key point is that it is diagnosed on positive signs, not simply because other tests are normal. The Brain Foundation explains that doctors look for characteristic patterns during a neurological examination. Brain imaging may be done to rule out other conditions, but results are often normal in FND.

An Australian article in the Medical Journal of Australia describes a rule-in approach. For example, leg weakness due to FND may vary with distraction, posture or activity. These features help doctors recognise FND with confidence.

FND can occur alongside other conditions

Having FND does not rule out other health problems. A person can have FND and epilepsy, or FND after a stroke or head injury. This is one reason a careful assessment by a neurologist matters, and why new or changing symptoms should always be checked.

The same article highlights the value of a clear explanation of the diagnosis. Understanding what FND is, and that it can improve, is often the first step in treatment.

Treatment and recovery

There is no single treatment for FND. The AIHW notes that while there is no cure, FND can be successfully managed with a multidisciplinary medical approach. Depending on symptoms, treatment may include:

• Education: understanding the diagnosis and how symptoms are produced
• Physiotherapy: retraining movement, often using techniques that shift attention away from the affected limb
• Occupational therapy: strategies for daily tasks, fatigue and returning to activities
• Speech pathology: for speech or swallowing symptoms
• Psychological therapy: such as cognitive behaviour therapy, which can help with symptom management, stress and any anxiety or low mood

Outcomes vary. The Brain Foundation notes that some people improve significantly or recover, while others continue to have ongoing symptoms. Getting a diagnosis and suitable treatment earlier may help.

Getting the most from appointments

Because FND affects people so differently, it helps to give your treating team a clear picture. You might:

• keep a simple diary of symptoms, what you were doing when they started, and what seems to help
• list your main goals, such as walking to the shops or returning to work
• bring a support person to help remember information
• ask for written information about FND to share with family, employers or teachers

Living with FND can be exhausting and isolating. If you are in danger, call 000. For 24-hour crisis support, call Lifeline on 13 11 14.

FND, memory and thinking: where neuropsychology fits

Thinking problems are common in FND. People describe forgetfulness, trouble concentrating, word-finding difficulties and mental fatigue. For some, these symptoms are the main problem, which is sometimes called functional cognitive disorder.

A systematic review by McWhirter and colleagues found that around a quarter of people seen in memory clinics received diagnoses that might indicate a functional cognitive disorder. These people are not developing dementia, and a correct diagnosis helps avoid unnecessary worry and treatment.

A neuropsychological assessment can help by:

• measuring attention, memory, language and processing speed in detail
• looking at how fatigue, pain, sleep, mood and anxiety affect everyday thinking
• helping the treating team tell functional cognitive symptoms apart from other causes
• providing practical strategies for work, study and home

How Invictus Health can help

Our neuropsychologists provide neuropsychology assessments that can help clarify thinking difficulties as part of wider FND care. We also offer counselling and psychology and can prepare NDIS assessments and reports where they are needed. We work alongside your GP and neurologist.

This article is general information and does not replace advice from your own doctor or treating team.