Conversion Disorder (Functional Neurological Disorder)

What conversion disorder is

The older term "conversion" came from the idea that emotional distress was "converted" into physical symptoms. Research now shows FND is better understood as a problem of brain functioning: attention, prediction and movement control networks work abnormally, like a software problem rather than a hardware fault. Stress and trauma can be risk factors, but many people with FND have no obvious psychological trigger, which is why the DSM-5-TR no longer requires one for diagnosis.

FND is one of the most common reasons for referral to neurologists. It occurs at any age, more often in women, and frequently starts after a physical event such as an injury, infection, migraine or surgery.

Symptoms

Motor symptoms

• weakness or paralysis of a limb or one side of the body
• tremor that changes in rhythm or stops with distraction
• jerks or spasms
• abnormal posture of a hand or foot (functional dystonia)
• dragging walk, buckling knees or unusual gait

Sensory symptoms

• numbness, tingling or loss of feeling
• blurred vision, tunnel vision or loss of vision
• hearing changes

Functional (dissociative) seizures

Also called psychogenic non-epileptic seizures (PNES). Attacks of shaking, collapse or unresponsiveness that look like epileptic seizures but are not caused by the abnormal electrical discharges of epileptic seizures. Eyes are often closed, attacks may last longer than epileptic seizures, and movements may wax and wane.

Other symptoms

• slurred, stuttering or whispering speech
• difficulty swallowing or a lump in the throat feeling
• cognitive symptoms such as memory and concentration problems
• fatigue and chronic pain often accompany FND

Causes and risk factors

• Physical triggers: injury, illness, migraine, pain, surgery
• Psychological factors: anxiety, depression, PTSD, childhood adversity, stressful life events
• Other conditions: somatic symptom disorder, epilepsy, migraine, multiple sclerosis and other neurological diseases can coexist with FND
• Brain mechanisms: excessive attention to the body, altered expectations of movement, and a reduced sense of control over movements

Diagnosis

FND is diagnosed by a neurologist based on positive clinical signs, not simply by excluding other conditions. Examples:

• Hoover's sign: weakness in hip extension that returns to normal when the person flexes the opposite hip against resistance
• Tremor entrainment: a tremor that changes to match a rhythm tapped by the other hand
• Distractibility: symptoms that improve when attention is directed elsewhere
• Video EEG: recording a typical attack with normal brain waves confirms functional seizures

MRI, EEG, nerve studies and blood tests are used to check for other conditions, which can coexist. A clear explanation of the diagnosis is itself an important part of treatment.

Treatment

Understanding the diagnosis

Learning that the symptoms are real, common and potentially reversible, and why they happen, is the first step. Many people find patient resources such as neurosymptoms.org helpful.

Physiotherapy

Specialized physiotherapy for functional motor disorder retrains movement using distraction, automatic movements and gradual practice rather than focusing on the weak limb. It is different from standard physiotherapy for injuries.

Psychological therapy

• Cognitive behavioral therapy (CBT): strong evidence for functional seizures and helpful for other symptoms
• Trauma-focused therapy when relevant
• Treatment of coexisting anxiety and depression

Other treatments

• occupational therapy for daily activities and fatigue
• speech and language therapy for speech and swallowing symptoms
• managing pain and sleep problems
• reducing medicines that are not helping, such as anti-seizure medicines in people who have only functional seizures

Outlook

Outcomes vary. Many people improve significantly with treatment, especially when diagnosis is early and they accept the explanation. Others have persistent or recurring symptoms, but can still learn to manage them. Long-standing symptoms are harder to treat, but improvement is possible at any stage.

Frequently asked questions

What is conversion disorder?

Conversion disorder is an older name for functional neurological disorder (FND). It causes real neurological symptoms, such as weakness, tremor, numbness or seizures, because the brain is not sending and receiving signals properly, even though the nervous system is not structurally damaged.

Are FND symptoms real or fake?

They are real. People with FND do not control or invent their symptoms. Brain imaging research shows differences in how the brain functions during symptoms. The symptoms can be as disabling as those of other neurological conditions.

What causes functional neurological disorder?

There is no single cause. FND often follows a physical trigger like an injury or illness. Stress, trauma, anxiety and depression raise the risk in some people. Changes in brain networks controlling attention and movement are thought to produce the symptoms.

How is FND diagnosed?

A neurologist diagnoses FND by finding specific positive signs on examination, such as Hoover's sign or a tremor that changes with distraction. For functional seizures, video EEG recording of an attack is the gold standard. Tests are also used to check for other conditions.

Can conversion disorder be cured?

Many people recover fully or improve substantially, particularly with early diagnosis and treatment. Specialized physiotherapy and cognitive behavioral therapy are the most effective treatments. Some people have ongoing symptoms but learn strategies to reduce their impact.