Understanding Functional Neurological Disorder: Causes, Symptoms and Treatment

Functional neurological disorder (FND) is an umbrella term that is used to describe a number of common neurological movement disorders. It’s thought that anywhere between 50,000 and 100,000 adults in the UK have the condition, but despite its prevalence, not many people are aware of what FND is, how it affects the body, and what treatment entails. 

In this article, we’re going to explore FND in more detail, outlining what causes it, what the symptoms are, and how the condition is managed. 

What is FND?

As mentioned, FND is an umbrella term that is given to a range of neurological movement disorders. It was formerly known as ‘conversion disorder’ or ‘functional neurologic symptom disorder’. 

When a person has FND, they will display a number of symptoms that are typically indicative of an issue in the nervous system, but there isn’t actually a physical neurological disorder or disease present that is responsible for the symptoms. To an extent, this means the symptoms are medically unexplained, but this doesn’t mean they’re not there. Instead, ‘functional’ means that, although there is no identifiable cause for the symptoms, it’s clear that the body isn’t working as it should be. 

Patients with FND have an issue with how their brain sends and receives information, but the specific issue can’t typically be traced back to a source because the structure of the brain and the nervous system appear to be working normally. 

For most people with FND, the symptoms tend to be short-lived, meaning they subside after a short while; however, in a small number of patients, symptoms can persist for months or even years at a time. In these instances, living a normal life can become difficult due to the nature of the symptoms. 

Symptoms of FND

There are a wide range of symptoms associated with FND, with most people finding they experience issues with their motor, sensory and cognitive functions. 

Motor Symptoms

Motor symptoms impact physical movements. In a person with functional movement disorder FND, common motor symptoms tend to include paralysis, tremors and abnormal movements. These are similar symptoms to those seen in neurological disorders like Parkinson’s disease (PD) and multiple sclerosis (MS), but as mentioned, FND doesn’t have the same underlying neurological cause. 

Sensory Symptoms

Sensory symptoms refer to feelings and sensations. Common sensory symptoms in FND typically include numbness, tingling and pain. These are similar to the symptoms seen in conditions like peripheral neuropathy or fibromyalgia, but without the same cause. 

Cognitive Symptoms

Cognitive symptoms affect how a person thinks. Cognitive symptoms often seen in people with conversion disorder FND include memory loss, confusion and difficulty concentrating. These symptoms are similar to those observed in conditions like dementia or a traumatic brain injury (TBI), but in people with FND, the brain shows no physical changes to cause the symptoms.

Psychogenic Nonepileptic Seizures

One of the main types of FND is called functional seizures, which causes psychogenic nonepileptic seizures. This is when a person has seizures that mimic epileptic seizures, but they don’t have epilepsy. Seizures can cause the sudden onset of uncontrolled shaking, unresponsiveness, or dissociation. 

It is important to note that there can be significant differences in FND symptoms between individuals. Some people may experience mild, fleeting symptoms, while others may have more severe and debilitating symptoms. 

The Importance of Understanding FND

Understanding FND is crucial for healthcare professionals and patients alike. For medical personnel, understanding functional neurological disorders can help them to provide more accurate diagnoses and effective treatments, especially because FND symptoms often mimic those of other neurological conditions. This can make determining an accurate diagnosis challenging, but with better insights and research, neurological healthcare professionals can better differentiate it from other disorders and provide appropriate treatment to alleviate and manage symptoms faster, resulting in enhanced patient outcomes.

For patients, understanding FND can provide validation and reassurance that their symptoms are real and not imagined, as many patients feel when there is no identifiable root cause for what they’re experiencing. Additionally, the more patients understand their condition, the more empowered they feel to participate in their own care and make informed decisions about their treatment. 

Causes of Functional Neurological Disorders

The causes of FND are complex and not fully understood. While there is no identifiable brain or nerve damage that can explain the symptoms, research has shown that psychological factors may play a significant role in the development of FND, as well neurotransmitter imbalances. Overall, FND is thought to be caused by a combination of psychological, environmental and biological factors, although more research is needed to fully understand the underlying causes of the condition.

Trauma / Abuse

Trauma and abuse, particularly childhood trauma or abuse, has been identified as a significant factor in the development of FND. Studies have shown that people diagnosed with FND are anywhere between two and four times more likely to have experienced trauma or abuse at some point in their life. We know that trauma can lead to changes in the brain and nervous system, which can affect how the body processes and responds to stress and high tension situations. 

We also know that many people with FND have a comorbid condition such as depression or anxiety, and such conditions can also be triggered by abuse and trauma. These factors could explain the onset of some FND symptoms. 

For example, some people who are anxious may develop a tremor or shake as a way to cope with what they’re feeling. Tremors can be a symptom of FND. Psychological interventions, such as therapy, have been shown to reduce FND symptoms in some patients with comorbid mental health conditions, suggesting that by addressing the potential trigger of the FND (such as trauma), FND symptoms may be better managed.

Childhood Trauma

Childhood trauma, including physical or sexual abuse, has been highlighted as one of the potential main triggers of FND in some people. There are several types of childhood trauma that have been linked to the development of the condition. These include:

  1. Physical abuse: This involves the use of physical force that causes harm or injury to a child. Examples include hitting, slapping, punching, and kicking.
  2. Emotional abuse: This includes any behaviour that causes emotional harm to a child, such as belittling, insulting, or rejecting them.
  3. Neglect: This refers to the failure of a caregiver to provide for a child’s basic needs, such as food, shelter, and medical care.
  4. Witnessing violence: This entails children being exposed to violence or abuse, such as seeing domestic violence between parents.
  5. Separation or loss: This involves the loss of a parent or caregiver through death, divorce, or other forms of separation.

All of these types of childhood trauma can have lasting effects on a child’s mental and physical health, and could contribute to the development of FND later in life.

Emotional Distress

Emotional distress can have a significant impact on the brain and nervous system, which could contribute to the development of FND. Chronic stress and emotional distress can lead to changes in the HPA axis, a system that regulates the body’s response to stress. These changes can lead to increased levels of stress hormones, such as cortisol, which can have negative effects on the brain and nervous system; particularly in areas involved in the processing of emotions and pain. These changes could contribute to the development of some FND symptoms, such as chronic pain, paralysis, or tremors.

Neurological Disorders

While FND can occur in isolation, it is also common for individuals with FND to have an existing neurological condition such as epilepsy or Ehlers Danlos syndrome (EDS).

The exact prevalence of FND in people with these conditions is not clear, but research suggests that they may be more susceptible to developing the condition nonetheless. 

For example, studies have found that people with epilepsy are more likely to experience non-epileptic seizures, which are a common manifestation of functional seizure type FND. Similarly, people with EDS may be at increased risk for developing FND symptoms related to joint hypermobility and pain.

It’s important to note that anyone can develop FND, and many people with the condition don’t have a pre-existing neurological condition, a comorbid mental health condition, or a history of trauma and/or abuse. More research is being done to further explore the causes of FND, but as yet, it’s thought that those who have a neurological condition, a traumatic or abusive past, and mood disorders are more predisposed to developing FND based on incidence rates observed so far. 

Diagnosing FND

Diagnosing functional neurological disorders can be challenging due to the wide range of symptoms and the fact they align with lots of other conditions. For this reason, diagnosing FND is often a process of elimination. This means lots of tests and scans may be done to determine what isn’t causing the symptoms. If symptoms persist and the tests show no neurological damage or conditions present, and there is no other viable explanation for the symptoms, an FND diagnosis may be made. 

To get to this stage, numerous neurological and psychological tests may be done. Neurological tests could include assessing motor function, sensation and reflexes, while psychological tests may include testing cognitive function and personality traits. Imaging studies, like MRI or CT scans, may also be used to evaluate the structure and function of the brain and rule out other conditions.

A closer look into life experiences and medical histories may also be taken in order to determine if there could be a predisposition to FND, such as a recent stressful event or a traumatic childhood. 

Treatment for FND

Due to the wide scope of symptoms, there are multiple different treatment options for FND. 


Medication is one of the main treatments for managing FND symptoms, with antidepressants, antipsychotics and anticonvulsants often used to manage symptoms such as anxiety, depression or seizures. 


Psychotherapy is another common treatment option for people with FND. Cognitive-behavioural therapy (CBT), psychoanalytic therapy and mindfulness-based therapy are all types of psychotherapy that can be helpful in managing certain FND symptoms.  

Alternative Therapies

Complementary and alternative therapies, such as acupuncture, yoga and meditation, may also be useful in managing FND symptoms. These therapies can help with things like stress management, which can exacerbate some FND symptoms.

Physical Therapy

Physical therapy is an important component of FND treatment. Physical therapists can help patients improve their physical function and reduce pain. There are several types of physical therapy that can be used for treating FND, including:

  • Rehabilitation therapy: This type of therapy focuses on improving physical function and reducing pain through exercise, stretching and other physical therapies.
  • Vestibular therapy: This involves focusing on improving balance and reducing dizziness or vertigo symptoms.
  • Gait training: This type of therapy helps people with FND to improve their ability to walk and move around.
  • Sensory re-education: This type of therapy is used to help patients retrain their senses, such as touch, sight and sound, to improve their ability to function overall.

In addition to physical therapy, occupational therapy may also be helpful in managing FND symptoms. Occupational therapists work to develop strategies for managing daily tasks and activities, such as self-care, work and leisure activities, all of which can be severely impacted by FND if it isn’t effectively managed.

A multidisciplinary approach to treatment is typically recommended for people with FND. This usually involves a team of varied healthcare professionals, including neurologists, psychiatrists, physical therapists, and occupational therapists, coming together to provide an advanced treatment plan that addresses most, if not all, of the symptoms of FND. 

Private Functional Neurological Disorder Specialists at Dementech

At Dementech Neurosciences, our team of leading neurologists provide expert advice, diagnostic services, and treatment for people with functional neurological disorders. Our team of specialists are committed to providing compassionate care and personalised, multidisciplinary treatment plans to help patients manage their symptoms and improve their overall quality of life. 

If you or a loved one is experiencing symptoms of FND, please contact us today to schedule a consultation with one of our experienced private neurologists.