What is Functional Neurologic Disorder?
Conversion disorder, also known as functional neurological symptom disorder (FND), is a type of mental health condition where a person shows symptoms affecting their sensory or motor functions. This means they may experience problems with their senses (like sight or touch) or movement. However, these symptoms are not consistent with patterns of known brain diseases or other medical conditions, making it a unique disorder.
Despite not being linked to any physical diseases, the symptoms of FND can greatly impact a person’s capacity to function or carry out day-to-day activities. On top of this, the person can’t control these symptoms by just deciding to, and they’re not pretending to have these symptoms on purpose.
Sigmund Freud, a renowned neurologist and the pioneer of psychoanalysis, was the first to discuss conversion disorder in medical literature. Freud thought that this disorder arose from an unconscious conflict, where mysterious symptoms that couldn’t be linked to brain diseases or other medical conditions reflected an internal, mental struggle. This is where the term “conversion” comes in, as it means trading a physical symptom with a suppressed idea or thought.
However, there is still much we do not know about functional neurological symptom disorder. Doctors and researchers are constantly learning more about this disorder and how to best approach treatment.
What Causes Functional Neurologic Disorder?
A functional neurological disorder can occur due to a mix of mental, social, and biological factors. Often, a stressful event or trauma precedes the onset of this disorder’s symptoms. It has been observed that many people who have this disorder have a history of childhood abuse. Other factors can contribute as well, like poor coping skills and internal mental conflicts.
People who have certain mental conditions, like depression, anxiety, and personality disorders, are more likely to have a functional neurological disorder. They are also more likely to report physical complaints, like fatigue, weakness, or pain, for which no medical cause can be found. Sometimes, a physical injury or a neurological illness, like a stroke or migraine, can “trigger” the symptoms of this disorder. It is more commonly found in less educated people, those with lower socioeconomic status, and those living in developing or rural areas.
There are two main theories to explain this disorder.
The first, known as the psychodynamic model, suggests that the physical symptoms are a result of emotional conflict. According to this model, these conflicts are pushed into the subconscious mind and change into a symptom. It claims that this is a defensive response against negative feelings. Other psychodynamic theories highlight the early development of inadequate coping mechanisms and negative interpersonal relationships. These coping mechanisms or behaviors may reappear later in life if the individual encounters another traumatic event.
The other model, the cognitive-behavioral model, implies that exposure to information about a specific symptom could create a memory of that symptom. When an individual excessively worries about or looks for signs of that symptom, this memory is “activated”. This activation could override the sensory input, transforming into an actual symptom. For instance, if an individual sees someone having a seizure in a movie, it could create a memory of this event. Later on, they might misinterpret feelings of anxiety, light-headedness, or dizziness as symptoms of an imminent seizure, leading them to experience a non-epileptic seizure. According to this model, behavioral and perceptual processing happens automatically and outside of a person’s awareness. It claims that symptoms of this disorder could result from unconscious psychological influences.
While there are many theories to explain this disorder, no single one explains all its aspects. For instance, some experts suggest that the role of specific brain cells, immunity, and changes in the control of synaptic plasticity, which is the brain’s ability to strengthen or weaken signals between cells, could explain motor dysfunctions associated with this disorder.
Risk Factors and Frequency for Functional Neurologic Disorder
Functional neurologic disorder is a condition that varies in frequency depending on the populations studied. Research has shown an average incidence of the disorder to be about 4 to 12 cases per 100,000 people each year. Some studies suggest higher rates for this disorder, placing it at around 50 cases per 100,000 people each year. A study of 3,781 patients at an outpatient neurology center found that roughly 5.6% had the disorder. However, another study with 7,836 patients found that only about 4% of patients showed symptoms of the disorder. It’s important to note, though, that this second study was done back in 1989.
Studies have found that functional neurologic disorder is more common in adult women than in adult men, with the ratio ranging from 2 to 1 up to 10 to 1. Individuals of lower socioeconomic status and with less education also have higher rates of this disorder. Meanwhile, the disease does not seem to be influenced by race. As for children, the disorder is rare in those under 5 and is most commonly seen during puberty and adolescence.
- The rate of functional neurologic disorder in children is largely based on the population studied.
- A study conducted in Germany found the rate of functional neurologic disorder in children to be 0.2%.
- An Australian study found the rate of functional neurologic disorder in children to be between 2.3 to 4.2 cases per 100,000 each year.
- Girls over ten years old are three times more likely to develop functional neurologic disorder than boys of the same age.
Signs and Symptoms of Functional Neurologic Disorder
Functional neurological disorder is a condition where patients experience physical symptoms that most tests can’t explain. To diagnose this condition, it’s crucial for doctors to build a rapport with the patient, encouraging them to share their history and symptoms. Important aspects to consider when evaluating a patient include:
- Listing of all current symptoms
- History of treatments and suspected diagnoses
- Time frame and context of symptoms
- Recent events or stressors, and psychiatric history
- Family history of psychiatric conditions
- Information about previous similar symptoms and their treatments
Though there are reliable indicators for diagnosing functional neurological disorders, such as inconsistent symptoms, negative lab results, and significant psychiatric disorder, it’s still vital to rule out other organic disorders. It should be noted that patients with this condition may also have coexisting neurological disorders, which can complicate diagnosis.
The Diagnostic and Statistical Manual of Mental Disorders (DSM-5TR) provides criteria for diagnosing functional neurological disorder:
- Presence of altered voluntary motor or sensory function symptoms
- Evidence of incompatibility between the symptoms and recognized neurological conditions
- Other medical or mental disorders don’t better explain the symptoms or deficit
- Significant distress or impairment resulting from symptoms or deficit
It’s important to note that an episode lasting less than six months is defined as acute, while one with symptoms lasting over six months is deemed persistent. The disorder can also be identified with or without a psychological stressor.
Several subtypes of functional neurologic disorder exist, and they include conditions like psychogenic nonepileptic seizures, paralysis or weakness, abnormal movement, sensory loss, swallowing symptoms, and speech symptoms. These subtypes exhibit a range of symptoms that need to be carefully observed by healthcare professionals for a proper diagnosis.
Testing for Functional Neurologic Disorder
The main methods doctors use to diagnose functional neurological disorder are usually asking about your medical history and a physical examination. However, in some cases, they might need to carry out some laboratory tests or scans to make sure that there aren’t any other medical issues causing your symptoms. What kind of tests or scans they order will depend very much on your symptoms and your condition at the time you see the doctor.
For example, if you’re showing signs which might suggest you’re having non-epileptic seizures – seizures that aren’t caused by some of the usual brain activity that leads to epilepsy – then your doctor might order an electroencephalogram. This test, often called an EEG, is used to keep track of your brain waves, and it might show that you’re not having a typical seizure. They might also do tests on your blood to check the levels of substances like prolactin or creatine phosphokinase. These tests can help tell the difference between an epileptic seizure and a non-epileptic one.
People whose main symptom is weakness might need to have tests like electromyography, which measures the electrical activity in your muscles, or magnetic resonance imaging (MRI), which creates detailed pictures of the body. These tests give doctors a lot of information about what’s going on in your body.
In addition, more tests may be ordered if your doctor thinks that you may have some sort of other health condition that is happening at the same time as your functional neurological disorder.
Treatment Options for Functional Neurologic Disorder
The first step in treating functional neurologic disorder, which is a condition where your nervous system doesn’t work properly even though it’s not damaged, involves explaining the diagnosis effectively. It’s generally recommended that doctors don’t disclose the diagnosis in the first meeting with the patient. Instead, it’s important for the doctor to build a good relationship with the patient. The doctor should be interested in what the patient thinks is wrong and encourage them to talk about how they feel about their symptoms.
In subsequent meetings with the patient, there are several important points the doctors should focus on:
- Emphasize that the patient’s symptoms are real and that the doctor understands the impact those symptoms have on their life.
- Don’t tell the patient that nothing is wrong with them or suggest that their condition is simply a psychological problem.
The doctor can also give examples of physical diseases that are worsened or brought on by stress. Explaining how the diagnosis was made can reassure the patient, especially if the doctor points out why this isn’t a physical neurological illness. The most important piece to emphasize is that the symptoms can possibly be reversed, because there isn’t any structural damage.
Therapy forms the first line of treatment for functional neurologic disorder. In particular, cognitive-behavioral therapy (CBT) is very helpful. CBT involves analyzing how a person thinks and feels about a situation, and how that affects their behavior. Other types of therapy like psychodynamic psychotherapy, group therapy, family therapy, and hypnotherapy – are also helpful.
Alongside therapy, physical therapy is also an effective first-line treatment. This approach is especially helpful for physical symptoms and assures patients that the medical team is taking their symptoms seriously. The physical therapist can help decrease symptoms by encouraging normal movements and working on more complex tasks at each session. Physical therapy can also prevent genuine weakness or deficit caused by the patient’s symptoms.
Medication is also effective when a mental illness, such as anxiety or depression, is present. Antidepressants, anxiolytics, or mood stabilizers will be chosen based on the underlying mental health condition. Some studies have also suggested that certain antidepressants can be helpful for treating the symptoms of functional neurologic disorder even if a mental health condition isn’t clearly present.
Other treatments like transmagnetic stimulation (TMS), which uses magnetic fields to stimulate nerve cells in the brain, might also be beneficial. However, there is limited scientific research on the effectiveness of this treatment. Regardless of the treatment utilized, it’s essential for patients to have regular follow-up appointments with all involved clinicians to ensure effective disease management and prevention of unnecessary visits to emergency care or urgent care facilities.
What else can Functional Neurologic Disorder be?
When dealing with the diagnosis of functional neurological disorder, doctors might consider the possibility of a number of psychiatric disorders that could show similar signs.
- Factitious disorder – Here, patients deliberately trick doctors by faking, exaggerating, or lying about symptoms, even to the extent of hurting themselves or manipulating their test results. Their goal is to be seen as ill and receive medical care, but not for personal or financial gain. Functional neurological disorder isn’t intentional like this.
- Somatic symptom disorder – This term collectively refers to what was previously known as somatoform disorders. It involves one or more physical symptoms that cause distress or a significant disruption to daily life, along with an excessive reaction to these symptoms. Some overlap may exist with functional neurological disorder, as patients often exhibit physical symptoms, but their reaction isn’t usually as extreme.
- Illness anxiety disorder – Previously known as “hypochondriasis”, patients obsess over the idea they have or will get a serious illness, even if they have few actual physical symptoms. They may obsessively check for signs of disease, or avoid doctors and hospitals. This kind of intense preoccupation is not typical in functional neurological disorder patients.
Note that malingering, though not a psychiatric disorder, could also be demonstrated. This involves someone pretending or exaggerating symptoms for personal or financial benefit, such as to avoid work or legal trouble, or to get hold of addictive medications. Contrary to people with factitious disorder, these individuals are generally less cooperative with medical examinations or treatments.
There are many general medical or neurological illnesses that may share features with functional neurological disorder. Some examples are:
- Multiple sclerosis – A demyelinating disease, where patients show signs of central nervous system dysfunction and typically follow a relapsing and remitting course. An MRI with characteristic brain and spinal cord lesions can confirm it.
- Epilepsy – Some differences exist between epileptic seizures and seizures found in functional neurological disorder, such as variations in serum prolactin levels. Seizures can also be triggered through placebo effect and photic stimulation during video-EEG monitoring.
- Myasthenia gravis – This is a disorder affecting the transmission between nerve and muscle, generating weakness in various muscles. Positive antibodies are often found in diagnostic tests, which can help confirm the diagnosis.
- Stroke – Strokes might cause a pattern of motor, sensory, or generalized neurological changes.
- Spinal disorders – Different spinal cord conditions may lead to motor and sensory disturbances that can be mistaken for functional neurological disorder. Examples include cervical myelopathy and spinal stenosis.
- Movement disorders – Functional movement disorders versus ones due to neurological conditions can lead to discrepancies in exam findings.
In the case of strokes, spinal disorders, and movement disorders, the important thing to note in functional neurological disorder is the inconsistencies in the patient’s neurological or anatomical pattern.
What to expect with Functional Neurologic Disorder
The outlook for a health condition called functional neurologic disorder isn’t usually very good. However, many things can influence this. If the disorder started suddenly, gets diagnosed early, has not lasted long, and there aren’t any other mental health disorders involved (particularly personality disorders), there’s a better chance of a positive outcome.
Having identified stress factors and a good relationship with your doctor can also help improve the situation. On the other hand, if patients experienced lots of physical symptoms or poor physical health before being diagnosed, they may have a higher risk of a less favorable outcome.
Possible Complications When Diagnosed with Functional Neurologic Disorder
Functional neurological disorder can lead to lasting disability and a reduced quality of life. Sometimes patients do not continue with their prescribed treatment or they become difficult to reach for follow up. Disability and impact on quality of life in patients with functional movement symptoms are similar to those in Parkinson’s disease, according to one study. Another study highlighted that patients with symptoms of paralysis experienced similar rates of disability to those with multiple sclerosis. Generally, people with psychogenic symptoms have a similar level of physical disability but a higher rate of psychological disability compared to those with actual neurological disorders.
Common Complications:
- Permanent disability
- Reduced quality of life
- Non-completion of prescribed treatment
- Patients becoming unreachable for follow ups
- Disability rates similar to Parkinson’s disease and Multiple Sclerosis
- Higher rates of psychological disability
Preventing Functional Neurologic Disorder
Teaching the patient all about their condition is a key part of the treatment for a functional neurologic disorder. It’s really important to provide them with resources they can read and discuss with their families. There are also support groups at a national level that the patient can join for additional help.
The doctor or healthcare worker should also try to have a separate conversation with the patient’s family to teach them how to positively reinforce the patient. The family should be encouraged to recognize that the patient’s symptoms are real, instead of simply telling the patient that they’re not really sick.
A supportive family can make a huge difference and they may also be able to help the healthcare worker find out what specific stress factors are causing the patient’s symptoms. The family can also help by making sure the patient goes to all their follow-up appointments and even participate in family therapy sessions.
Lastly, it’s important to understand that the diagnosis of a functional neurologic disorder can add to the family’s stress levels too. Because of this, they should be encouraged to join support groups specifically for individuals who have family members with mental health conditions.
