Definition

Functional neurological disorder (FND) is a condition in which there is a problem with how the brain receives and sends information to one or more parts of the body. FND is not caused by a disease or injury. For reasons not understood, the nervous (neurological) system does not work properly.

FND symptoms may include weakness and paralysis of the limbs, seizures, tremors and jerks, and other nervous system symptoms.

Alternative Names

Conversion disorder; Functional neurological symptom disorder

Causes

FND has no known cause. However, stress or a mental or physical trauma can trigger FND. It can also occur with no known trigger.

Certain factors may make a person more susceptible to FND:

• Having another neurological condition
• Having a mental health condition
• Chronic pain or fatigue
• Ongoing life stress
• Childhood abuse, neglect, or trauma

FND is uncommon in children under age 10. Before age 50, it is more likely to occur in women. After age 50 it affects both men and women equally.

While the cause of FND is unclear, this condition and its symptoms are real. It causes serious distress and cannot be turned on and off at will.

Symptoms

FND can cause a variety of symptoms that affect body movement, senses, and thinking:

• Vision problems (double vision or blindness)
• Speech problems (slurred speech or loss of speech)
• Numbness or loss of sensation
• Hearing problems
• Memory problems
• Trouble concentrating
• Pain
• Fatigue
• Weakness or paralysis
• Tremors, spasms, jerkiness, tics
• Involuntary repetitive movements
• Difficulty walking
• Loss of balance
• Difficulty swallowing
• Seizures or episodes of shaking and loss of consciousness (not caused by epilepsy)

Exams and Tests

There is no one single test for FND. Your provider will do physical, neurological, and psychiatric exams and may order diagnostic tests. These are to check for medical causes of the symptom.

Treatment

Treatment for FND will depend on what symptoms you experience. You may work with different providers, including:

• Neurologists
• Mental health professionals
• Primary care clinicians
• Speech, physical, or occupational therapists

Treatments may include:

• Talk therapy
• Cognitive behavior therapy to help alter thought patterns, emotions, behaviors and mood
• Relaxation and mindfulness exercises to manage stress
• Physical, speech, and occupational therapy
• Other treatments as necessary

It can also help to learn about FND and understand that your symptoms are real, even without a medical cause. Knowing that there is no serious medical cause may help you feel less anxious and more able to cope.

Support Groups

More information and support for people with FND and their families can be found at:

• FindHope.org - fndhope.org/what-we-do/support-blogs-groups/
• National Organization for Rare Disorders - rarediseases.org/rare-diseases/fnd/#program-resources

Outlook (Prognosis)

Symptoms usually last for days to weeks and may suddenly go away while others may last for years. The symptom itself is usually not life threatening, but complications can be debilitating.

When to Contact a Medical Professional

See your provider or mental health professional if you or someone you know has symptoms of functional neurological disorder.

References

American Psychiatric Association. Somatic Symptom and Related Disorders. Diagnostic and Statistical Manual of Mental Disorders. Fifth Edition, Text Revision (DSM-5-TR). Washington, DC: American Psychiatric Association Publishing; 2022.

Gerstenblith TA, Kontos N. Somatic symptom disorders. In: Stern TA, Fava M, Wilens TE, Rosenbaum JF, eds. Massachusetts General Hospital Comprehensive Clinical Psychiatry. 2nd ed. Philadelphia, PA: Elsevier; 2016:chap 24.