What is FND
Functional Neurological Disorder (FND) is a condition where there is a problem with how the brain and nervous system function, rather than a structural disease or damage. In plain terms, you might think of it as a “software” issue with the brain’s signalling, not a “hardware” issue. The basic wiring of the brain and nerves is intact, but the signals are getting misinterpreted or disrupted. This means individuals with FND experience very real neurological symptoms, even though standard scans or tests often show no lesion or damage.
Symptoms
FND can produce a wide range of symptoms. In fact, FND is known as a “brain network” disorder encompassing diverse neurological symptoms. For example, it can cause:
- Tremor: shaking in an arm or leg that may come and go and sometimes stops if the person is distracted.
- Functional Dystonia: painful muscle spasms that may cause a hand to clench, a foot to twist, or facial spasms.
- Functional Myoclonus: sudden jerks or jumps in the body.
- Functional Tics: quick, repeated movements or sounds that happen without control.
- Walking difficulties: problems such as dragging a leg, sudden knee buckling, unsteady steps, or feeling like walking on ice.
- Weakness: an arm or leg that feels heavy or unable to bear weight. This can also affect bladder or bowel control.
- Paralysis: temporary loss of movement in part of the body, lasting hours or even days. This can look similar to a stroke.
Functional and Dissociative Seizures (previously called Non-Epileptic Attack Disorder, NEAD) may look like epileptic seizures but are not caused by unusual electrical activity in the brain. They can still happen alongside epilepsy or other FND symptoms. They may involve blackouts, collapsing, twitching, or jerking. Sometimes people are aware of what’s happening around them but cannot respond.
Strange sensations (such as skin crawling, shocks, or twitches), sensitivity (being overly affected by light, sound, smell, touch, or taste), and cognitive issues (difficulties with memory, concentration, speech, or finding words) can also occur.
This very useful NHS site contains lots of useful information about FND - Click here to find out more
In real life, FND symptoms can look very different from one person to another. One person might suddenly be unable to walk, while another may have frequent blackouts or non-epileptic seizures. Some people develop unusual symptoms such as functional tics or even changes in their voice or accent. Symptoms can appear gradually or all at once, and their intensity often rises and falls, especially during times of stress or tiredness.
It’s important to understand that FND is both real and common. It can affect people of any age, and for many, the symptoms are serious, disabling, and can significantly change day-to-day life. Research suggests that up to a third of neurology clinic visits involve functional symptoms. So if you have FND, you’re not alone, and you’re not “imagining” your symptoms—your nervous system is experiencing a functional disruption.
Causes of FND can include...
Physical or biological factors
For example, a head injury, the body’s response to surgery, or an illness like a viral infection.
Psychological or social factors
Such as traumatic life events or ongoing stress, which can trigger FND symptoms.