What is FND?

Functional Neurological Disorder (FND) is one of the most common yet misunderstood conditions seen in neurology today. Despite affecting millions of people worldwide, many patients still leave appointments feeling confused, dismissed, or unsure how their symptoms could be “real” when their tests come back normal.

Let’s change that.

This blog breaks down what FND is, where the diagnosis came from, why stigma still lingers, and how people can access the right treatment and support.

What Exactly Is FND?

Functional Neurological Disorder occurs when the brain has difficulty sending and receiving signals correctly with the body. Many FND analogies exist, but you can think of it like a software issue rather than a hardware problem — the system is intact, but the communication isn’t flowing the way it should.

This mismatch can lead to symptoms such as:

• Changes in movement or control

• Weakness or paralysis

• Sensory changes

• Functional seizures

• Cognitive changes or brain fog

Even though these symptoms are very real and often very disabling, routine medical tests often appear “normal" or "unremarkable." That’s because the structure of the brain is intact — it’s the functioning that’s disrupted. Today, neurologists use positive clinical signs or tests to confirm FND, not simply rule out other conditions.

FND can also bring along “secondary” symptoms like chronic pain, fatigue, and anxiety related to the sudden loss of control or independence. Because the brain interprets functional changes as internal stress, treatment works best when it supports both the mind and the body.

A Complicated History (and Why Stigma Still Exists)

FND has been around for centuries — just under different names, each shaped by the beliefs of the time.

Supernatural Explanations

Hundreds of years ago, sudden changes in movement or consciousness were attributed to spirits or divine forces. Treatment involved prayer or rituals meant to drive out the cause.

Hysteria

As medicine evolved, symptoms were blamed on the uterus — especially since FND is more common in women. Treatments ranged from perfumes to marriage to dietary changes. Not exactly evidence‑based.

Conversion Disorder

Freud and Breuer reframed symptoms as psychological responses to trauma. For decades, treatment focused solely on psychotherapy. This term still exists in diagnostic manuals, but our understanding has moved far beyond it.

Functional Neurological Disorder (FND)

Only in the last decade has the diagnosis shifted to reflect modern neuroscience. We now know FND is multi‑factorial, involving brain networks, stress responses, learning mechanisms, and physical triggers. Treatment requires a combination of physical rehabilitation and psychological support.

Given this long, winding history, it’s no surprise that stigma and outdated beliefs still show up in medical settings. Some training programs still teach FND primarily as a conversion disorder, while others — especially in the UK — have begun integrating modern FND education into neurology and rehabilitation.

How Common Is FND? More Than Most People Realize

FND is not rare, it is underdiagnosed. In fact:

• It’s the second most common diagnosis seen in neurology clinics.

• 1 in 6 neurology referrals involve FND.

• Millions of people worldwide are living with this condition.

By age group:

• Children/Teens: ~18 per 100,000 (likely underestimated)

• Adults: 80–140 per 100,000 in recent studies

Despite these numbers, many patients still struggle to find clinicians who understand the condition well. And even more astonishing, with the stigma and lack of training that exists, misdiagnosis rates remain around 5% which is similar to other neurological disorders.

Who Treats FND? A Team Approach Works Best

FND recovery is strongest when multiple disciplines work together:

• Neurology: diagnosis, medical oversight, and treatment planning

• Psychology/Psychiatry: identifying triggers, building coping strategies, supporting return to roles

• OT / PT / ST: movement retraining, sensory regulation, ADL/IADL reintegration, pacing, routine building, and functional task engagement

This collaborative model helps patients rebuild confidence, independence, and control over their symptoms.

Where to Learn More

Reliable, patient‑friendly information is essential. Here are trusted places to start:

• RewireOT.com: What is FND + treatment at Rewire OT (Ellisville, MO) both in-person and virtual treatment options.

• Neurosymptoms.org: symptom explanations, videos, and handouts

• FNDHope.org: advocacy, education, and support groups

• Regional providers and community groups: local support and treatment options