Functional neurological disorder (FND) is a problem with how the brain and nervous system work, not with their structure. Scans are usually normal. The symptoms are real, and they are not under voluntary control. FND can cause seizure-like attacks, weakness in an arm or leg, tremor and other movement problems, and memory or concentration difficulties.
A neurologist diagnoses FND from positive signs found on examination, such as Hoover's sign. A normal scan on its own is not enough. Treatment starts with understanding the diagnosis. Then comes rehabilitation: FND-informed physiotherapy, occupational therapy, psychological therapy or speech therapy, as needed. Two large UK trials, one of physiotherapy and one of CBT, both missed their main target. Both still improved several other outcomes. Some people recover well. Others live with symptoms for years.
NHS inform, Scotland's health information service, uses a computer comparison. In FND there is no damage to the hardware, the structure of the brain. It is the software that is not working properly.
NHS inform says the problem happens at a level of the brain you cannot control. Neurologist Jon Stone's patient guide, neurosymptoms.org, puts it simply: people with FND are not imagining it. Older or alternative names include "conversion symptoms", "psychogenic" and "non-epileptic attacks".
NHS inform lists several reasons the brain can start working this way. There is often more than one:
Stressful events, PTSD, depression or anxiety are relevant for some people and not for others. The risk rises if you have another neurological condition, and may rise with autism or ADHD. If trauma is part of your story, our guide to what the guidelines recommend for PTSD covers treatment for that separately.
FND can also sit alongside other conditions. NHS inform says that in around a quarter of cases it occurs with another neurological condition, such as epilepsy or multiple sclerosis.
FND is one of the most common reasons people see a neurologist. A study of 3,781 new patients across all NHS neurology centres in Scotland recorded the diagnoses neurologists made. "Functional and psychological symptoms" was the second most common category, at 16%. Only headache was more common, at 19%. That category is broader than FND alone, so treat 16% as an approximate share.
In Ireland, the HSE estimates that up to 10,000 people are living with FND.
Sources: NHS inform and neurosymptoms.org.
Neurosymptoms.org notes that functional tremor is the most common functional movement disorder. It is sometimes mistaken for Parkinson's or essential tremor. Our guide to essential tremor versus Parkinson's explains how those two differ.
NHS inform lists other FND symptoms: numbness or pins and needles, speech and swallowing problems, visual symptoms and sudden falls. It also includes persistent postural perceptual dizziness (PPPD), a constant dizziness that worsens when walking or in crowds. Most people with PPPD also have another cause of dizziness at the same time. Our guide to vertigo, BPPV and vestibular neuritis covers the common ones.
Other problems often come along with FND. NHS inform lists chronic pain, fatigue, sleep problems, migraine, irritable bowel syndrome, anxiety, depression and PTSD. Our guide to chronic pain and central sensitisation covers the pain side.
NHS inform is clear on this. FND should be diagnosed because you have clinical features typical of FND. It should not be diagnosed just because scans or tests are normal. Your doctor may still order tests, partly because FND can coexist with other conditions.
A key feature is that movement is often worse when you try hard, and better when it is automatic. Neurosymptoms.org describes several signs that use this.
Hoover's sign (leg weakness). You try to push the foot of your weak leg down into the bed, and it is weak. The doctor then asks you to push up with your other leg. As you do, strength in the weak leg returns. When your attention is on the other leg, automatic movement comes back. That shows the weakness is not caused by damage.
Entrainment test (tremor). You copy a rhythm with your unaffected hand. A functional tremor may stop briefly or change its rhythm.
Seizures. The specialist asks you and witnesses what happens and looks at any video footage. NHS inform gives eyes closing during attacks as one typical feature. If doctors are unsure, an EEG with video, recorded during an attack, can help. It shows an abnormal pattern in epileptic seizures, but not in functional seizures.
Is the diagnosis often wrong? A 2005 systematic review of 27 studies (1,466 patients with motor or sensory symptoms) found misdiagnosis rates of about 4% in studies since 1970. Earlier studies reported much higher rates, which the authors linked to poorer study quality. A Scottish follow-up study of new neurology patients whose symptoms were judged unexplained by disease went further. After 18 months, only 4 of 1,030 (0.4%) had a new disease diagnosis that explained their original symptoms.
NHS inform describes FND treatment as rehabilitation therapy. It aims to "retrain the brain" and improve everyday function. Some people go into remission. Others keep symptoms despite treatment.
FND-informed physiotherapy differs in many ways from rehabilitation after a stroke. Rather than trying hard to move a weak leg, you might kick a ball or focus on a spot ahead, using automatic movement.
The key trial is Physio4FMD, published in The Lancet Neurology in 2024. It enrolled 355 adults with functional motor disorder at 11 hospitals in England and Scotland. People got either nine sessions of specialist physiotherapy plus follow-up, or a referral to community neurological physiotherapy.
There are caveats. COVID-19 disrupted the trial, and 89 participants were excluded from the main analysis. The comparison group still got physiotherapy, just not the specialist kind. The usual-care group also waited longer to start treatment. And the authors note that most outcomes, including the main one, were self-reported.
CODES, published in The Lancet Psychiatry in 2020, randomised 368 adults with dissociative seizures. Everyone got standardised medical care. Half also got CBT designed for dissociative seizures.
The secondary results were not corrected for multiple comparisons, so they are less certain than the primary result. The authors concluded that adults with dissociative seizures "might benefit" from adding this CBT to specialist care.
NHS inform also lists occupational therapy, speech and language therapy and psychological therapy. Not everyone needs psychological therapy. Medication can help related problems such as pain, depression or anxiety. NHS inform notes that some medicines, including opiates such as codeine, can make FND worse. Do not stop any prescribed medicine without talking to your doctor.
Fatigue is common in FND. If your fatigue crashes a day or two after effort, tell your team. That pattern, post-exertional malaise, is central to ME/CFS, where NICE advises against graded exercise therapy. Our guide to post-exertional malaise explains that change.
NHS inform calls FND "a really variable condition". Some people have short-lived symptoms. Others have them for many years.
Most of the long-term data covers motor symptoms. A 2014 systematic review of 24 studies found that, on average, 39% of people were the same or worse at follow-up. The range across studies was very wide, from 10% to 90%. Most studies looked back at records, and the review left out studies of specific treatments.
The same review found a shorter duration of symptoms, early diagnosis and high satisfaction with care predicted better outcomes in two studies. Delayed diagnosis predicted worse outcomes. A 2023 analysis of 8 studies (348 people) with functional limb weakness found no clear evidence that depression or anxiety worsened the outcome.
Start with your GP, who can refer you to a neurologist. If you already have a diagnosis, ask your neurologist what FND-informed physiotherapy, occupational therapy or psychology is available locally.
In Ireland, services are still being built. In May 2026 the HSE set out its position in two parliamentary replies:
That gap is widely felt. In a 2024 national survey of 314 Irish healthcare professionals, 85% said people with FND lacked access to appropriate services. FND Ireland is a volunteer-run, not-for-profit organisation offering information, peer connection and advocacy.
In the UK, NHS inform's FND guide is a good starting point. Other trusted sources include:
In an emergency. The NHS says to call 999 for an ambulance if it is someone's first seizure. Also call if it lasts longer than usual for them, or over five minutes if you do not know. Call too if they are seriously injured or struggle to breathe afterwards. In Ireland, 112 and 999 are both free. If you are struggling with low mood or thoughts of suicide, Samaritans are free on 116 123 in Ireland and the UK. In the US, call or text 988.
No. NHS inform says FND happens at a level of the brain you cannot control. Positive signs like Hoover's sign show how the nervous system is working. They do not show that someone is pretending.
Usually not. Scans in FND typically show no damage to explain the symptoms. That is why diagnosis rests on positive signs found on examination.
Yes, for some people, though not for everyone. NHS inform says some people go into remission with treatment. Others continue to have symptoms.
Not on your own. Some people have both epilepsy and functional seizures. Any change to anti-seizure medicine should be planned with your neurologist.
This article is general information, not medical advice. It does not replace an assessment by your GP or neurologist. Do not start, stop or change any medicine without talking to your doctor.
Reviewed by: Proco Team
Last updated: November 2026