Functional Neurological Disorders

Disease/Disorder

Definition

Conversion disorder (CD) is a condition now also referred to as Functional Neurological Symptom Disorder (FNSD) classified in DSM-5 as related to Somatic Symptom Disorder (SSD).  FNSD presents with motor and/or sensory symptoms initially suggesting identifiable neurologic pathology as the potential cause. However, subsequent diagnostic evaluation fails to reveal neurological structural disease as the etiological explanation for the symptoms.¹ When FNSD presents primarily as an abnormality of voluntary movement—either a lack or an excess of movement—the term Functional or Psychogenic Movement Disorder (PMD) has been employed. Presentation is typically acute in onset and symptoms may develop consequent to a psychologically conflictual situation, although anticipated psychological distress linked to the potentially ominous somatic symptoms may not be evident. In contrast to Factitious Disorder (FD), symptoms are not simulated through conscious intention in FNSD, although specific symptom form and plausibility may be influenced by the patient’s prior experiences, degree of medical sophistication, and cultural background. The clinical distinction between FNSD and the consciously simulated symptomatology of FD is difficult and can often only be definitively made with a confession of deceit or when the patient is caught out in a broader deception or with covert surveillance.² When, in addition to being aware of willful simulation of symptoms, the patient consciously intends the presentation of symptomatology for the purpose of tangible secondary gain, then the patient meets criteria for a diagnosis of malingering.

A partial list of more common FNSD symptoms includes paralysis or paresis, involuntary movements, abnormal gait, blindness, sensory alteration, and psychogenic nonepileptic seizures (PNESs).

Diagnostic criteria (all must be met) for FNSD based on the DSM-5 include:

• One or more symptoms of altered voluntary motor or sensory function.
• Clinical findings providing evidence of incompatibility between the symptom(s) and recognized neurological or medical conditions.
• The symptom(s) or deficit(s) are not better explained by another medical or mental disorder.
• The symptom(s) or deficit(s) cause clinically significant distress or impairment in social, occupational, or other important areas of functioning, and/or warrant medical evaluation.

It should be noted that the diagnosis of FNSD does not definitively exclude the possibility of coexistent and potentially overlapping organic disease.

Etiology

FNSD was originally considered purely psychologic in etiology and described as a physical manifestation of psychological distress. However, this understanding has changed over time. Now, FNSD is considered a disease at the intersection of psychiatry and neurology.³ As such, the updated DSM-V diagnostic criteria no longer require the presence of precipitating psychological distress. The etiology is not fully elucidated but is thought to be a complex interplay of predisposing factors, including but not limited to history of trauma/stress, somatic symptoms, illness exposure, symptom monitoring and neurobiological factors.⁴ Increasing research is being done that explores the specific neurobiological changes seen in individuals with FNSD. Through functional imaging, abnormalities have been identified in regions of the brain involved in self-agency, emotional processing, and attention-related processes.⁴

Epidemiology including risk factors and primary prevention

Epidemiologic studies are limited by inconsistencies in case definition (e.g., medically unexplained physical symptoms vs true FNSD) and inaccurate case ascertainment. Some associated factors are given in Table 1.

Table 1. Epidemiology of FNSD

RRR: relative risk ratio

An increased incidence in relatives of probands with FNSD has been reported suggesting a genetic predisposition. Psychogenic seizures may occur in up to one fifth of patients referred for assessment to an epilepsy treatment center.⁶

A large meta-analysis of case-control studies examined the history of stressful life events and maltreatment in FNSD. The study established increase OR of FNSD given certain history of maltreatment.⁷

 OR: Odds ratio

Patho-anatomy/physiology

Functional neuroimaging studies have found multiple areas of impaired communication between brain systems, including areas involved in motor conceptualization, sensation, self-agency, emotion control, attention and perception.⁸ Patients with motor FNSD have shown increased responsivity and reduced habituation in the amygdala to emotionally provocative stimuli. An abnormally strong functional linkage between the amygdala and the supplementary motor area (SMA) of the nondominant right hemisphere has been identified in functional neuroimaging.⁹ The SMA is involved in voluntary movement selection and the regulation of internally generated action. A recently published systematic review and meta-analysis of neuroimaging studies in FNSD patients reports that multiple areas that are important for motor-planning, motor-selection or autonomic response seem to be especially relevant.⁸

Disease progression including natural history, disease phases or stages, disease trajectory (clinical features and presentation over time)

As noted, onset can be correlated with acute psychological stress or a personal social crisis; however, this is not always seen. As a result, the DSM-V definition of FNSD no longer requires the presence of a precipitating psychological stressor for the diagnosis of FNSD.

Symptoms usually have a rapid and intense onset, having a significant impact on the individual’s function and quality of life. There can be periods of spontaneous remission and/or fluctuation in symptom severity.¹⁰ Overall, the disease trajectory of FNSD is quite variable with some individuals achieving remission while others have persistent symptoms for years. Chronicity may relate to severity and persistence of the underlying stress, untreated superimposed or coincident psychiatric difficulties, the comorbid presence of a personality disorder, or continuing environmental reinforcement. Early diagnosis and early access to treatment including physical and psychological therapy is crucial to recovery for these patients.¹⁰

Specific secondary or associated conditions and complications

FNSD is a diagnosis to be entertained only after excluding an organic etiology for the symptoms. In less than 5% of cases, an organic condition eventually surfaces.³ Psychiatric comorbidities, such as depression, anxiety, and personality disorders, as well as other functional somatic disorders, such as irritable bowel syndrome, are frequently seen.³ Patients usually deny emotional difficulty and resist psychodynamic formulation and psychiatric consultation. Over-aggressive pursuit of a medical explanation with multiple diagnostic tests or initiation of inappropriate medical treatments can precipitate iatrogenic complications.

Essentials of Assessment

History

A detailed comprehensive history can identify if there may be a viable organic etiology to be considered and excluded.¹⁰ A comprehensive psychosocial history is critically important. Developing stressors or historical traumatic experiences may be disclosed if a trusting patient-practitioner relationship can be established. History can mirror symptom severity and the extent to which symptoms currently interfere with daily function. Besides FNSD, conversion symptoms can be seen in conjunction with other clinical conditions including somatization disorder, substance abuse, affective disorder, and can overlap with co-morbid organic neurologic or medical illnesses.

Physical examination

Physical examination with attention to mental status and neurologic signs should be completed. The distribution and type of impairment often is not homogeneous with neuroanatomical pathways. Specific signs (e.g., Hoover’s sign, give-way weakness, contralateral sternocleidomastoid weakness) can help distinguish organic impairment from functional illness but cannot differentiate between FNSD and malingering. Under the DSM-V, these positive physical examination signs are used to “rule-in” the diagnosis of FNSD.¹⁰ Pathologic reflexes indicate organic etiology. Patients may overstate or functionally heighten manifestations of underlying organic pathology further complicating the assessment and adding to variability of clinical observations across different examiners.

Functional assessment

Functional testing should also be observed as incompatible findings on formal examination and behavior in functional situations often occur. For example, a patient who is unable to lift an upper extremity during the examination may do so while grooming. Observation of gait and mobility may also show inconsistent limitations and sometimes bizarre or incongruent non-physiologic patterns of motor impairment. Patients may show blunted or conflicting emotional responses of indifference/preoccupation regarding implications of reported symptoms. Insight and judgment are often diminished or impaired.

Laboratory studies

Laboratory studies should be judiciously utilized to exclude organic causes. Sensory-evoked potentials can document normal physiologic pathway transmission. With PNESs, electroencephalography with simultaneous video monitoring may be considered, although a normal result does not exclude organic seizures. A prolactin level drawn 30 minutes after a seizure is elevated after organic, but not after nonepileptic seizures.

Imaging

Normal imaging of the brain and spinal cord can help eliminate organic conditions or developing pathology, such as multiple sclerosis/neoplasm.

Supplemental assessment tools

Standardized health status questionnaires and symptom inventories can assess outcomes. Depression scales and anxiety measures can help assess psychiatric comorbidity. The use of a scale to assess occurrence of stressful life events can help to identify associated sources of stress.¹¹ Measures of health care utilization can assess reduced dependence on provider services.

Early predictions of outcomes

Longer duration of symptoms, expectation of nonrecovery, untreated psychiatric comorbidity, tremor and/or nonepileptic seizures at the time of initial consultation are associated with worse prognosis.¹²

Environmental

Environmental factors can play an important role in the development of FNSD. An association has been found between childhood and adult stressful life events and FNSD. While a preceding psychological stressor is no longer needed for diagnosis of FNSD, they are still considered risk factors and are seen in some individuals with FNSD.⁷

Social role and social support system

The depth and breadth of the individual’s relational communication and support matrix (including intrapersonal, interpersonal, and sociocultural factors) determines a patient’s timeline regarding seeking assistance/participation in recommended treatments. And to some extent, the eventual functional outcome and prognosis.

Professional issues

Variance between patient and practitioner may result from disagreement regarding etiology. Persisting symptoms can incite feelings of powerlessness, mistrust, as well as provider frustration, which can impair therapy.¹⁵ Owens and Dein emphasized the importance of not labeling patients as manipulative, dependent or as exaggerating their difficulties, to preserve a functional therapeutic alliance.¹³ Avoid confronting and appeasing the patient with unnecessary interventions. Assume an empathic approach that affirms symptom credibility while focusing on a course of practical and functional improvement measures, rather than an extensive search for an elusive organic explanation. Take care in discussing the diagnosis with the patient.^15,16,17

Rehabilitation Management and Treatments

Discussing the diagnosis

The first step of management is appropriately addressing this new diagnosis and educating the patient and the family. It is in the patients’ best interest to tactfully educate them on their diagnosis as well as their prognosis. When patients do not believe that their illness is functional in nature and when they do not believe they are going be able to recover, patients are twice as likely to have poor outcomes at a year after diagnosis.¹⁵ Many authors have given different versions of how to deliver this diagnosis as patients can be sensitive to accepting it.

It can be helpful to reiterate the test results, state that it is a good thing that no stroke, seizures, or other abnormalities were found on testing. Reassure the patient that the symptoms they are experiencing are real and that they will need to receive follow up for these symptoms from some combination of neurology, psychiatry, psychology, physical therapy, occupational therapy and physiatry since they have “what is called a ‘functional neurological disorder’ or ‘FNSD.’” The clinician should explain that many patients with FNSD have been found to have a history of trauma or abuse in their past and that is why it will be important to include psychiatry and psychology in on the team to help them fully address the roots of their symptoms. Reassure the patient that even though there was nothing observed on imaging, that does not mean that these symptoms are not real. Therefore, follow up is important.¹⁷

Given the nature of this disorder, acceptance and understanding can take a while. For this reason, educational materials provided to the family are beneficial.¹⁶

Many clinicians may avoid the burden of informing the patient of their diagnosis for fear of imparting the stigma of mental disorder on the patient and documenting as such. However, delaying the delivery of this diagnosis will result in unnecessary medical costs, multiple opinions from subsequent clinicians, and worse patient outcomes.^15,16

Pharmacotherapy

Currently, the diagnosis of FNSD is not specifically an indication for any pharmacotherapy. No placebo-controlled randomized trials exist to date. Evidence for antidepressants only comes from a few uncontrolled studies.¹⁶ However, co-existing conditions, such as anxiety, depression, and irritable bowel syndrome, should be treated if present. For individuals with PNES confirmed to not have a co-existing seizure disorder, antiepileptic therapy should be discontinued.¹⁶ Although there is a high correlation between psychiatric disorders and FNSD, psychogenic medication only has anecdotal evidence of efficacy.

Psychological therapy

Cognitive behavioral therapy (CBT) has been shown to be effective in the treatment of functional neurological disorders including psychogenic non-epileptic seizures.^15,16,17 CBT for individuals with FNSD often includes education regarding the diagnosis, bottom-up regulation interventions, and when indicated, family therapy.⁴

Physical and occupational therapy

Benefit has been noted for as long as a year after three weeks of inpatient physical therapy (PT) and occupational therapy (OT).¹⁷ This was assessed in a randomized control trial with 60 patients with a disabling walking gait who had been experiencing symptoms for 1-48 months. Patients exhibited a statistically significant lasting increase in FIMS score, decreased need for assistive devices, and increased physical quality of life at 12 months. The interdisciplinary team consisted of physician, PT, OT, nurse, and adapted physical activity educator, but no psychologist. It should be noted that a core component of cognitive behavioral therapy (CBT) involves rewarding good behavior. This makes it more nuanced to separate the benefits of physical and occupational therapy from CBT.¹⁷

In 2020, consensus recommendations were created by a group of physiotherapists, neurologists, and neuropsychiatrists, with extensive experience treating individuals with functional motor disorders.¹⁶ These stated that treatment should focus on education, movement retraining and self-management strategies with the goal of addressing illness beliefs, self-directed attention and habitual movement patterns.

Patient exercise progression should be stepwise and incorporate increasingly challenging movement tasks as used with analogous neurological disorders.¹⁶ The progression would proceed as follows: establish rapport, engage in bed mobility and general strengthening, then progress to walking in the parallel bars, followed by open spaces, and eventually ambulating in the community. This progression can be altered to address each individual patient’s clinical presentation, symptoms, and overall function. Staffing changes should be kept to a minimum to foster an environment of increasing rapport and trust.

The need for inpatient versus outpatient therapy should be evaluated similarly to individuals without a functional neurological disorder based on requirements for inpatient rehabilitation.

Coordination of care

Effective treatment of FNSD is best undertaken with a multidisciplinary team allowing for comprehensive interdisciplinary collaboration to provide holistic patient-centered care and ultimately improve outcomes for patients with FNSD.^15,16

Patient & family education

Transparent treatment includes education of the patient and caregivers regarding the nature of the problem and its management. This includes constructive explanations of physical symptoms linked to strategies for reducing their functional impact.¹⁶ It is important to ensure that caregivers are aware of how they can assist the patient by reinforcing progress toward independence rather than rewarding symptom manifestation.

Families provide essential roles in participating in the patient’s formal PT/OT in order to carry over the progress made during therapy into the patient’s home environment. Family members will also be able to learn by example of therapists demonstrating to ignore unwanted behavior and reward desired behavior.

Emerging/unique interventions

With increasing research and knowledge regarding FNSD, there has been development of multidisciplinary clinics dedicated to treating individuals with FNSD. These centers bring together neurologists and neuropsychiatrists as well as direct connections to clinical psychologists and rehabilitation physicians and therapists with the goal of providing patient-centered holistic care for this population.¹⁸

Translation into practice: practice “pearls”/performance improvement in practice (PIPs)/changes in clinical practice behaviors and skills

• Insight-oriented psychotherapy or short-term cognitive-behavioral therapy in conjunction with conventional rehabilitation therapies can be of benefit.
• More resistant chronic cases may require strategic double-bind behavioral therapy.
• Care should be patient-centered, multidisciplinary and collaborative, creating an expectation for recovery and return to full independence.
• Keep the focus on pragmatic recovery of meaningful function with the expectation for functional improvement and effective symptom management despite not being able to determine a specific causative mechanism.
• Pay attention to contributing environmental and contextual psychosocial factors.

Cutting Edge/Emerging and Unique Concepts and Practice

Smith and Dwamena proposed a comprehensive approach to patients with medically unexplained physical symptoms (MUPS), including CD.¹⁹ Patients are classified according to 3 dimensions: symptom severity (mild, moderate, and severe), duration (acute, subacute, and chronic), and comorbidity (psychiatric, medical, or both). Clinical management decisions, such as the extent to which one should pursue diagnosis of an underlying organic disease, can then be guided by this scheme. The authors propose that this approach facilitates successful and cost-effective symptom management.

Recent research suggests distorted interoception and a disturbance involving the ‘sense of body ownership’ and ‘sense of agency’ in patients with FNSD. Patients demonstrate reduced interoceptive-based bodily awareness with a retained sense of body ownership similar to dissociative disruption seen in other disorders of self-awareness, embodiment and agency. Other studies suggest that it is the sense of agency that is impaired in PMD as evidenced by decreased action-effect binding.

Transcranial magnetic stimulation

In 2014 a systematic review was performed by Pollak et al. of the use of Transcranial Magnetic Stimulation (TMS).²⁰ They looked at ten publications that addressed the effects before and after the use of TMS in 95 patients with MUPS. The authors concluded that despite most of the individual studies reporting TMS as a successful treatment, results remain inconclusive. Pollack et al concluded this due to lack of placebo controls, subjective outcome measures, transient effects, a low threshold to deem success (often less than 50% improvement in functional outcome measures), inadequate volume of TMS to produce neuromodulation and inappropriate placement of stimulation for effective neuromodulation. They posit that most of the studies were insufficient, and that there was too much heterogeneity in the studies to perform an appropriate meta-analysis determining effectiveness one way or the other.

Difficulty with studying FNSD

FNSD is difficult to study for various reasons. Primarily, there are many different types of FNSD – motor, sensory, dissociative, epileptic, etc.¹⁰ Treatment requires a multidisciplinary approach, which makes studying individual therapies difficult.¹⁰ There is also an ethical issue of using a randomized control trial for the patients receiving placebo – is it appropriate to place individuals in a placebo group? If so for how long? Additionally, the lack of consistency in nomenclature over the years adds complexity to systematic review on the topic. The various terminology used by the different versions of the DSM as well as International Classification of Diseases include functional neurological disorder, conversion disorder, psychogenic non-epileptic seizures, and hysteria.¹⁰

Gaps in the Evidence-Based Knowledge

While over the last few decades there has been significant growth in research, there are still many gaps in our knowledge and treatment of FNSD. Further elucidation of the specific pathophysiology of this disorder is needed and vital to ultimately guide improvements in individualized treatment plans. In addition, studies that evaluate long-term outcomes for individuals with FNSD would be helpful in determining a more precise disease trajectory, prognosis, and determining the value of different interventions.

References

1. Aybeck S, Kanaan RA, David AS. The neuropsychiatry of conversion disorder. Curr Opin Psychiatry. 2008;21:275-280.
2. Allin M, Streeruwitz A, Curtis V. Progress in understanding conversion disorder. Neuropsychiatr Dis Treat. 2005;1:205-209.
3. Fobian AD, Elliott L. A review of functional neurological symptom disorder etiology and the integrated etiological summary model. J Psychiatry Neurosci. 2019 Jan 1;44(1):8-18. doi: 10.1503/jpn.170190. PMID: 30565902; PMCID: PMC6306282.
4. Perjoc RS, Roza E, Vladacenco OA, Teleanu DM, Neacsu R, Teleanu RI. Functional Neurological Disorder-Old Problem New Perspective. Int J Environ Res Public Health. 2023 Jan 8;20(2):1099. doi: 10.3390/ijerph20021099. PMID: 36673871; PMCID: PMC9859618.
5. Roelofs K, Spinhoven P, Sandijck P, Moene FC, Hoogduin KA. The impact of early trauma and recent life-events on symptom severity in patients with conversion disorder. J Nerv Ment Dis. 2005;193:508-514.
6. Benbadis SR, Allen Hauser W. An estimate of the prevalence of psychogenic non-epileptic seizures. 2000;9:280-281.
7. Ludwig L, Pasman JA, Aybek S, David AS, Tuck S, Kanaan RA, Roelofs K, Carson A, Stone J. Stressful life events and maltreatment in conversion (functional neurologic) disorder: systematic review and meta-analysis of case-control studies. The Lancet Psychiatry. 2018; 5(4):307
8. Perez DL, Nicholson TR, Asadi-Pooya AA, Bègue I, Butler M, Carson AJ, David AS, Deeley Q, Diez I, Edwards MJ, Espay AJ, Gelauff JM, Hallett M, Horovitz SG, Jungilligens J, Kanaan RAA, Tijssen MAJ, Kozlowska K, LaFaver K, LaFrance WC Jr, Lidstone SC, Marapin RS, Maurer CW, Modirrousta M, Reinders AATS, Sojka P, Staab JP, Stone J, Szaflarski JP, Aybek S. Neuroimaging in Functional Neurological Disorder: State of the Field and Research Agenda. Neuroimage Clin. 2021;30:102623. doi: 10.1016/j.nicl.2021.102623. Epub 2021 Mar 11. PMID: 34215138; PMCID: PMC8111317.
9. Voon V, Brezing C, Gallea C, et al. Emotional stimuli and motor conversion disorder. Brain. 2010;133:1526-1536.
10. Aybek S, Perez DL. Diagnosis and management of functional neurological disorder. BMJ. 2022 Jan 24;376:o64. doi: 10.1136/bmj.o64. PMID: 35074803.
11. Nicholson TR, Aybek S, Craig T, et al. Life events and escape in conversion disorder. Psychol Med. 2016;46:2617-2626.
12. Gelauff J, Stone J, Edwards M, Carson A. The prognosis of functional (psychogenic) motor symptoms: a systematic review. J Neurol Neurosurg Psychiatry. 2014 Feb;85(2):220-6. doi: 10.1136/jnnp-2013-305321. Epub 2013 Sep 12. PMID: 24029543.
13. Owens C, Dein, S. Conversion disorder: the modern hysteria. Adv Psychiatr Treat. 2006;12:152-157.
14. Gilmour GS, Nielsen G, Teodoro T, Yogarajah M, Coebergh JA, Dilley MD, Martino D, Edwards MJ. Management of functional neurological disorder. J Neurol. 2020 Jul;267(7):2164-2172. doi: 10.1007/s00415-020-09772-w. Epub 2020 Mar 19. PMID: 32193596; PMCID: PMC7320922.
15. O’Neal MA, Baslet G. Treatment for patients with a functional neurological disorder (conversion disorder): an integrated approach. Am J Psychiatry. 2018;175:4:307-314.
16. Nielsen G, Stone J, Matthews A, Brown M, Sparkes C, Farmer R, Masterton L, Duncan L, Winters A, Daniell L, Lumsden C, Carson A, David AS, Edwards M. Physiotherapy for functional motor disorders: a consensus recommendation. J Neurol Neurosurg Psychiatry. 2015 Oct;86(10):1113-9. doi: 10.1136/jnnp-2014-309255. Epub 2014 Nov 28. PMID: 25433033; PMCID: PMC4602268.
17. Jordbru AA, Smedstad LM, Klungsoyr O, et al. Psychogenic gait disorder: A randomized controlled trial of physical rehabilitation with one-year follow-up. J Rehabil Med. 2014;46:181-187.
18. Aybek, Selma, et al. “What is the role of a Specialist Assessment Clinic for FND? lessons from three National Referral Centers.” The Journal of Neuropsychiatry and Clinical Neurosciences, vol. 32, no. 1, Jan. 2020, pp. 79–84, https://doi.org/10.1176/appi.neuropsych.19040083.
19. Smith RC, Dwamena FC. Classification and diagnosis of patients with medically unexplained symptoms. J Gen Intern Med. 2007;22:685-691.
20. Pollack TA, Nicholson TR, Edwards MJ, et al. J Neurol Neurosurg Psychiatry. 2014;85:191-197.

Original Version of the Topic

Gary Goldberg, MD. Conversion disorder. 11/27/2012

Previous Revision(s) of the Topic

Gary Goldberg, MD. Conversion disorder. 3/27/2017

Antonio Quidgley-Nevares, MD, Justin Faye, MD, Eben Alexander IV, DO, Michael Guju, MD, Roberto Austin. Conversion Disorder. 6/16/2022

Author Disclosure

Samantha DiSalvo, MD
Nothing to Disclose

Yelim Chung, MD
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Hana Azizi, MD, MPH
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