Functional neurological disorder (FND) is a condition in which a person experiences temporary physical symptoms, such as blindness or paralysis, that do not have a physical cause.

While the exact cause of functional neurological disorder is unknown, researchers believe it can be in response to stressful situations or trauma, and changes in the way the brain networks function.

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Historically, it is thought that FND was a physical response to mental, physical, or psychological trauma. However, the exact causes are unknown, and certain factors that are unique to each individual may trigger or exacerbate the symptoms. MRI studies actually show abnormal connections, and sometimes connections increase to certain areas of the brain. At other times, connections decrease.

Symptoms include shaking, paralysis, or double vision.

Triggers can include:

  • stressful events
  • emotional or physical trauma
  • changes in brain function at the structural, cellular, or metabolic level
  • illnesses such as the flu

FND may also occur when there is no apparent trigger, and a person may have other vulnerabilities that make the above triggers possible to activate FND.

The exact cause, however, varies from person to person. While researchers have speculated that the cause relates to stressful events, the precise medical reason is still unknown.

Some of the symptoms of FND typically include:

A person may not have them all at the same time.

Symptoms of FND vary between individuals and depending on the type of neuralgic disorder a person has.

Symptoms can be mild or severe, may stop and start or be continuous, and usually affect the body’s ability to function correctly.

A doctor will diagnose FND using the most recent Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria. These criteria include:

  • loss of control of movement or sensory symptoms
  • symptoms that do not appear to have an underlying medical or physical cause
  • symptoms that interrupt a person’s everyday activities

A doctor may also suggest other tests to rule out other medical conditions. These tests include:

Once diagnosed, there are a variety of ways to treat FND.

Anyone experiencing symptoms of FND should seek immediate medical attention, as an underlying medical condition may cause the symptoms.

Suggested treatments for FND may include:

FND symptoms are real and distressing but there is no underlying structural problem with the nervous system. Usually, this is good news as it means that a person does not have a serious neurological disorder such as multiple sclerosis (MS) or epilepsy. FND is a common disorder and many people recover from FND with proper supports.

The symptoms of FND can be very distressing and may have an impact on a person’s well-being. Symptoms may prohibit them from carrying out everyday activities.

Specific symptoms, such as seizures or temporary paralysis, may increase a person’s risk of disability. It is crucial to seek a diagnosis and treatment as quickly as possible.

Treatments such as psychotherapy and physical therapy can help a person live a typical life with FND.

The first signs of FND include:

  • weakness
  • paralysis
  • seizures
  • tremors
  • sensory difficulties such as numbness or pain
  • cognitive issues such as memory loss or difficulty concentrating

Triggers for FND may be unique to the individual, but may include:

  • stress or trauma
  • physical illnesses
  • underlying neurological conditions

The symptoms of FND usually resolve with treatment and time. Delaying diagnosis and treatment could lead to more persistent symptoms and further complications.

With treatment, it is possible to reduce and manage the symptoms of FND.

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