Functional neurologic disorder (FND), also known as conversion disorder and functional neurologic symptom disorder, refers to a group of common neurological movement disorders caused by an abnormality in how the brain functions. FND is not caused by another disorder and there is no significant structural damage in the brain. The exact cause of FND is unknown. FND was thought to be a “conversion disorder” by Sigmund Freud because he believed a psychological disorder converted into a neurological one.

Someone with FND can function normally, they just can't at that moment. Their brain is unable to send and receive signals properly and there is a disconnection in the function of the lobes and emotional processing. Memory, concentration, cognition, and the processing of sensations also can be affected.

FND causes real symptoms that significantly interfere with how you function and cope with daily life. If you have FND, your unplanned movements and symptoms occur without you consciously starting them and are inconsistent and distinct from symptoms that are intentionally produced. FND can involve any part of your body. Symptoms may appear suddenly, increase with attention to them, and decrease when you are distracted.

FND can be difficult for you, your family, and doctors to understand. Early diagnosis and treatment can help lessen symptoms and aid in healing.

Anyone can develop FND. An estimated four to 12 people per 100,000 will develop FND. Fundamental causes may involve biological factors (such as early childhood trauma and early life stress, emotions, a propensity of anxiety, witness to violence, maltreatment, or childhood sexual abuse) or sociological factors (including interpersonal relationships and stress). Some of these factors can trigger episodes of FND.

The disorder is more common in women and particularly in those who have a history of early life sexual trauma. It can occur but is uncommon in children under age 10. There appears to be an association with depression and anxiety, early life trauma, a dysfunctional family life, and even a dislike of job.

FND sometimes has a psychological cause as one of the relevant factors and may result from a somatic symptoms disorder (characterized predominantly by multi-system symptoms that are associated with distress and/or dysfunction and look like a physical illness).

FND has two primary categories:

1. Psychogenic nonepileptic seizures (PNES)
2. Functional movement disorder (FND)

There are many types of FND, with a diverse mix and range of neurologic symptoms and disorders. For some people, symptoms are short-lived, while they may last for years for others.

Psychogenic nonepileptic seizures (PNES) may look like generalized or other forms of epileptic seizures but are caused by brain dysfunction and not by abnormal electrical signaling in the brain. You may have episodes of movement, sensation, and behavior similar to an epileptic seizure and may have a temporary loss of attention or memory lapse. You also may have confusion or loss of consciousness without shaking. You might feel “disassociated” (or somewhat disconnected) from thoughts or feelings or from the environment.

PNES can be stress-related, emotional, or psychological reactions to an inability to cope with a sudden or past event or events. They mostly affect women and often begin in young adulthood. Seizures may be frequent and prolonged. With proper treatment, PNES may cease in some individuals or reduce in frequency. Children and adolescents with PNES tend to have a higher rate of recovery.

Functional movement disorder (FND) affects movement of the body. Symptoms may include:

• Leg and arm weakness or paralysis
• Tremor
• Sudden, brief involuntary twitching or jerking of a muscle or group of muscles (myoclonus)
• Involuntary muscle contractions that cause slow repetitive movements or abnormal postures (dystonia)
• Problems with walking motion (gait), posture, or balance
• Spasms and contractures (in which the tendons become fixed in awkward or uncomfortable positions)
• Muscle stiffness
• Tics

Symptoms that affect other brain functions may include:

• Speech difficulties, such as sudden onset of stuttering or trouble speaking
• Problems with seeing or hearing
• Pain (including chronic migraine)
• Extreme slowness and fatigue
• Numbness or inability to sense touch

No single test can confirm a diagnosis of FND. A doctor will assess your health and medical and family history to rule out any neurological or other condition that may cause symptoms since FND can co-exist with other disorders.

A neurologist and a psychiatrist or psychologist may look for specific patterns of symptoms or signs to make a diagnosis.

Tests include physical, neurologic, and psychiatric exams, as well as imaging scans, in part to rule out other disorders, and examine symptoms such as tremor, weakness, walking, and vision.

Other tests such as electromyography (which records the electrical activity in muscles) and electroencephalography (which monitors the brain's electrical activity) can help identify a movement disorder. Video electroencephalography, which records what you are seeing or doing over a period of time (from several hours to days) while brain waves are being recorded until a seizure occurs, can help diagnose PNES and determine if other seizures that have unusual features are actually epilepsy.

• Prepare for your appointment by making a list of any symptoms you may be experiencing, a list of all of your medications, and a list of questions for your doctor. Be sure to include any family history of illnesses or trauma. Be prepared to answer questions about your past experiences, any mental health concerns you may have, and any recent social, emotional, or other life changes. Bring a notepad to take notes.

• Speak honestly with your doctor or primary health care specialist about your symptoms and consider an evaluation by a neurologist and a psychiatrist. Learning all you can about your disorder and knowing that your symptoms are real can help with your recovery and treatment options. Speak with your doctor about resources and support groups for you and your family. You may wish to bring a family member or friend for support and to help you remember what the doctor said.

• Work with your care team to set treatment goals and define an effective outcome.

• Lifestyle changes such as exercising, eating a balanced diet, participating in relaxation exercises, and getting enough sleep can help you reduce stress and anxiety.

There are no specific treatments for FND but there are treatments for some of its symptoms. A team of doctors and health professionals from various specialties work together to deliver a combination of treatments and comprehensive care. Learning that your symptoms are real despite there not being an underlying medical disease can help you to better cope with the disease, become motivated to making change, and aid in recovery. It's also possible to learn techniques to lessen your symptoms. You and your medical team will schedule follow-up appointments. Your family also should be involved to help understand FND and to support you as you deal with your symptoms, treatment, and any stigma associated with the disorder.

• Medications: Medications are available to treat pain, anxiety, depression, insomnia, or headache that may occur. Any anti-seizure medications prescribed to treat nonepileptic seizures should be discontinued, as the attacks of PNES and those of epilepsy are not the same and are treated differently.
  
• Psychotherapy: Psychotherapy involves having you talk with a licensed and trained mental health professional about negative or troublesome emotions, behaviors, and thoughts. Cognitive behavior therapy (CBT) can help you modify your thought patterns to change emotions, mood, or behavior. Psychodynamic therapy can help you identify and resolve patterns in your thoughts, beliefs, and emotions that may cause some of the neurological symptoms. Relaxation and mindfulness exercises can help reduce stress. Some individuals benefit from hypnosis to induce relaxation and lessen FND symptoms.
  
• Physical, speech, and occupational therapy: Physical therapy can treat muscle weakness or impaired movement. You might need to relearn normal movement control and ways to avoid excessive attention to abnormal movements. Occupational therapy is designed to improve how you function and perform everyday tasks. You might need speech therapy if your ability to speak or swallow is affected.
  
• Redirecting attention: FND symptoms might increase when your attention is directed to unwanted movements. Redirecting attention from the abnormal movement, such as having a conversation while the movement is taking place or tapping an unaffected arm or leg, can lessen your movement or other symptom.
  
• Other treatments: Transcranial magnetic stimulation (which uses magnetic fields generated outside your skull to stimulate nerve cells in the brain) is used to treat depression and anxiety and transcutaneous electrical stimulation (which uses low-voltage noninvasive electrical current to activate nerves) is used to relieve pain.

If you have PNES with warning signs you may be able to learn techniques to avoid symptoms. Be aware that relapses and flare-ups often recur, despite treatment.

NINDS researchers are studying the neurobiology of FND and nonepileptic seizures, as well as any clinical association of the effects of the COVID-19 pandemic on individuals with functional movement disorder.

Scientists funded by the NIH are working to better understand the underlying neuropathology of FND and are using magnetic resonance imaging to develop neuroimaging biomarkers—signs that may indicate risk of developing a disease or be used to monitor its progression—for FND and nonepileptic seizures. Among other research, investigators hope to develop a test to diagnose and better treat PNES and to test medications for PNES.