Functional neurological symptom disorder

There are a great number of symptoms experienced by those with a functional neurological disorder. While these symptoms are very real, their origin is complex, since it can be associated with severe psychological trauma and idiopathic neurological dysfunction.{{Cite web|title=Functional neurologic disorders/conversion disorder - Symptoms and causes|url=https://www.mayoclinic.org/diseases-conditions/conversion-disorder/symptoms-causes/syc-20355197|access-date=2022-01-04|website=Mayo Clinic|language=en}} The core symptoms are those of motor or sensory dysfunction or episodes of altered awareness:{{Cite web|date=2022-01-05|title=Functional neurological symptom disorder|url=https://www.medicalnewstoday.com/articles/318534|access-date=2022-01-08|website=www.medicalnewstoday.com|language=en}}{{Cite web|title=Functional neurologic disorders/conversion disorder - Symptoms and causes|url=https://www.mayoclinic.org/diseases-conditions/conversion-disorder/symptoms-causes/syc-20355197|access-date=2022-01-08|website=Mayo Clinic|language=en}}{{Cite web|title=Functional Neurological Disorder|url=https://www.physio-pedia.com/Functional_Neurological_Disorder|access-date=2022-01-08|website=Physiopedia|language=en}}{{Cite web |title=Symptoms – Functional Neurological Disorder (FND) |url=https://www.neurosymptoms.org/en_GB/symptoms/ |access-date=2022-08-18 |language=en-GB}}

• Limb weakness or paralysis
• Non-epileptic seizures – these may look like epileptic seizures or faints
• Movement disorders including tremors, dystonia (spasms), myoclonus (jerky movements)
• Visual symptoms including loss of vision or double vision
• Speech symptoms including dysphonia (whispering speech), slurred or stuttering speech
• Sensory disturbance including hemisensory syndrome (altered sensation down one side of the body)
• Numbness or inability to sense touch
• Dizziness and balance problems
• Pain (including chronic migraines)
• Extreme slowness and fatigue

A systematic review found that stressful life events and childhood neglect were significantly more common in patients with FNSD than the general population, although some patients report no stressors.{{cite journal | vauthors = Ludwig L, Pasman JA, Nicholson T, Aybek S, David AS, Tuck S, Kanaan RA, Roelofs K, Carson A, Stone J | display-authors = 6 | title = Stressful life events and maltreatment in conversion (functional neurological) disorder: systematic review and meta-analysis of case-control studies | journal = The Lancet. Psychiatry | volume = 5 | issue = 4 | pages = 307–320 | date = April 2018 | pmid = 29526521 | doi = 10.1016/S2215-0366(18)30051-8 | hdl = 2066/187770 | url = https://discovery.ucl.ac.uk/id/eprint/10074178/ }}

Converging evidence from several studies using different techniques and paradigms has now demonstrated distinctive brain activation patterns associated with functional deficits, unlike those seen in actors simulating similar deficits. {{Cite book |doi = 10.1016/b978-0-12-801772-2.00007-2|chapter = Imaging studies of functional neurologic disorders|title = Functional Neurologic Disorders|series = Handbook of Clinical Neurology|year = 2016| vauthors = Aybek S, Vuilleumier P |volume = 139|pages = 73–84|pmid = 27719879|isbn = 9780128017722}} The new findings advance current understanding of the mechanisms involved in this disease, and offer the possibility of identifying markers of the condition and patients' prognosis.{{Cite web|date=2019-11-28|title=Imaging Study Provides New Biological Insights on Functional Neurological Disorder|url=http://www.itnonline.com/content/imaging-study-provides-new-biological-insights-functional-neurological-disorder|access-date=2022-01-08|website=Imaging Technology News|language=en}}{{cite journal | vauthors = Bennett K, Diamond C, Hoeritzauer I, Gardiner P, McWhirter L, Carson A, Stone J | title = A practical review of functional neurological disorder (FND) for the general physician | journal = Clinical Medicine | volume = 21 | issue = 1 | pages = 28–36 | date = January 2021 | pmid = 33479065 | pmc = 7850207 | doi = 10.7861/clinmed.2020-0987 }}

FNSD has been reported as a rare occurrence in the period following general anesthesia.{{cite journal | vauthors = D'Souza RS, Vogt MN, Rho EH | title = Post-operative functional neurological symptom disorder after anesthesia | journal = Bosnian Journal of Basic Medical Sciences | volume = 20 | issue = 3 | pages = 381–388 | date = August 2020 | pmid = 32070267 | pmc = 7416177 | doi = 10.17305/bjbms.2020.4646 }}

A diagnosis of a functional neurological disorder is dependent on positive features from the history and examination.{{cite journal | vauthors = Espay AJ, Aybek S, Carson A, Edwards MJ, Goldstein LH, Hallett M, LaFaver K, LaFrance WC, Lang AE, Nicholson T, Nielsen G, Reuber M, Voon V, Stone J, Morgante F | display-authors = 6 | title = Current Concepts in Diagnosis and Treatment of Functional Neurological Disorders | journal = JAMA Neurology | volume = 75 | issue = 9 | pages = 1132–1141 | date = September 2018 | pmid = 29868890 | pmc = 7293766 | doi = 10.1001/jamaneurol.2018.1264 }}

Positive features of functional weakness on examination include Hoover's sign, when there is weakness of hip extension which normalizes with contralateral hip flexion.{{cite journal | vauthors = Sonoo M | title = Abductor sign: a reliable new sign to detect unilateral non-organic paresis of the lower limb | journal = Journal of Neurology, Neurosurgery, and Psychiatry | volume = 75 | issue = 1 | pages = 121–125 | date = January 2004 | pmid = 14707320 | pmc = 1757483 }} Signs of functional tremor include entrainment and distractibility. The patient with tremor should be asked to copy rhythmical movements with one hand or foot. If the tremor of the other hand entrains{{clarify|date=May 2025}} to the same rhythm, stops, or if the patient has trouble copying a simple movement this may indicate a functional tremor. Functional dystonia usually presents with an inverted ankle posture or clenched fist.{{cite journal | vauthors = Thenganatt MA, Jankovic J | title = Psychogenic tremor: a video guide to its distinguishing features | journal = Tremor and Other Hyperkinetic Movements | volume = 4 | pages = 253 | date = 27 August 2014 | pmid = 25243097 | pmc = 4161970 | doi = 10.7916/D8FJ2F0Q }}

Positive features of dissociative or non-epileptic seizures include prolonged motionless unresponsiveness, long duration episodes (>2 minutes) and symptoms of dissociation prior to the attack. These signs can be usefully discussed with patients when the diagnosis is being made.{{cite journal | vauthors = Mellers JD | title = The approach to patients with "non-epileptic seizures" | journal = Postgraduate Medical Journal | volume = 81 | issue = 958 | pages = 498–504 | date = August 2005 | pmid = 16085740 | pmc = 1743326 | doi = 10.1136/pgmj.2004.029785 }}{{cite journal | vauthors = Pick S, Rojas-Aguiluz M, Butler M, Mulrenan H, Nicholson TR, Goldstein LH | title = Dissociation and interoception in functional neurological disorder | journal = Cognitive Neuropsychiatry | volume = 25 | issue = 4 | pages = 294–311 | date = July 2020 | pmid = 32635804 | doi = 10.1080/13546805.2020.1791061 | s2cid = 220410893 | doi-access = free }}{{Cite web| vauthors = Wiginton K |title=What Is Dissociation?|url=https://www.webmd.com/mental-health/dissociation-overview|access-date=2022-01-08|website=WebMD|language=en}}{{cite journal | vauthors = Adams C, Anderson J, Madva EN, LaFrance WC, Perez DL | title = You've made the diagnosis of functional neurological disorder: now what? | journal = Practical Neurology | volume = 18 | issue = 4 | pages = 323–330 | date = August 2018 | pmid = 29764988 | pmc = 6372294 | doi = 10.1136/practneurol-2017-001835 }}

Patients with functional movement disorders and limb weakness may experience symptom onset triggered by an episode of acute pain, a physical injury or physical trauma. They may also experience symptoms when faced with a psychological stressor, but this isn't the case for most patients. Patients with functional neurological disorders are more likely to have a history of another illness such as irritable bowel syndrome, chronic pelvic pain or fibromyalgia but this cannot be used to make a diagnosis.

FNSD does not show up on blood tests or structural brain imaging such as magnetic reasonance imaging (MRI) or CT scanning. However, this is also the case for many other neurological conditions so negative investigations should not be used alone to make the diagnosis. FNSD can occur alongside other neurological diseases and tests may show non-specific abnormalities which cause confusion for doctors and patients.{{cite journal | vauthors = Stone J, Smyth R, Carson A, Lewis S, Prescott R, Warlow C, Sharpe M | title = Systematic review of misdiagnosis of conversion symptoms and "hysteria" | journal = BMJ | volume = 331 | issue = 7523 | pages = 989 | date = October 2005 | pmid = 16223792 | pmc = 1273448 | doi = 10.1136/bmj.38628.466898.55 | doi-access = free }}

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) lists the following diagnostic criteria for functional neurological symptom disorder:

1. One or more symptoms of altered voluntary motor or sensory function.
2. Clinical findings can provide evidence of incompatibility between the symptom and recognized neurological or medical conditions.
3. Another medical or mental disorder does not better explain the symptom or deficit.
4. The symptom or deficit results in clinically significant distress or impairment in social, occupational, or other vital areas of functioning or warrants medical evaluation.{{cite book | vauthors = Peeling JL, Muzio M | chapter = Conversion Disorder |date=2022 | chapter-url=http://www.ncbi.nlm.nih.gov/books/NBK551567/ | title = StatPearls |access-date=2023-03-05 |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=31855394 }}

The presence of symptoms defines an acute episode of functional neurological symptom disorder for less than six months, while a persistent episode includes the presence of symptoms for greater than six months. FNSD can also have the specifier of with or without the psychological stressor.

Epidemiological studies and meta-analysis have shown higher rates of depression and anxiety in patients with FNSD compared to the general population, but rates are similar to patients with other neurological disorders such as epilepsy or Parkinson's disease. This is often the case because of years of misdiagnosis and accusations of malingering.{{cite book |title=Gates and Rowan's nonepileptic seizures. |vauthors=Fiszman A, Kanner AM |date=2010 |publisher=Cambridge University Press |isbn=978-0-521-51763-8 |veditors=Schachter SC, LaFrance Jr WC |edition=3rd |location=Cambridge |pages=225–234}}{{cite journal |vauthors=Henningsen P, Zimmermann T, Sattel H |year=2003 |title=Medically unexplained physical symptoms, anxiety, and depression: a meta-analytic review |journal=Psychosomatic Medicine |volume=65 |issue=4 |pages=528–533 |doi=10.1097/01.psy.0000075977.90337.e7 |pmid=12883101 |s2cid=4138482}}{{cite journal |vauthors=Edwards MJ, Stone J, Lang AE |date=June 2014 |title=From psychogenic movement disorder to functional movement disorder: it's time to change the name |journal=Movement Disorders |volume=29 |issue=7 |pages=849–852 |doi=10.1002/mds.25562 |pmid=23843209 |s2cid=24218238}}{{cite journal |vauthors=Kranick S, Ekanayake V, Martinez V, Ameli R, Hallett M, Voon V |date=August 2011 |title=Psychopathology and psychogenic movement disorders |journal=Movement Disorders |volume=26 |issue=10 |pages=1844–1850 |doi=10.1002/mds.23830 |pmc=4049464 |pmid=21714007}} Multiple sclerosis has some overlapping symptoms with FNSD, potentially a source of misdiagnosis.{{cite journal | vauthors = Walzl D, Solomon AJ, Stone J | title = Functional neurological disorder and multiple sclerosis: a systematic review of misdiagnosis and clinical overlap | journal = Journal of Neurology | volume = 269 | issue = 2 | pages = 654–663 | date = February 2022 | pmid = 33611631 | pmc = 8782816 | doi = 10.1007/s00415-021-10436-6 }}

Non-epileptic seizures account for about 1 in 7 referrals to neurologists after an initial episode, while functional weakness has a similar prevalence to multiple sclerosis.{{cite journal |vauthors=Stone J |date=March 2011 |title=Functional neurological symptoms |journal=The Journal of the Royal College of Physicians of Edinburgh |volume=41 |issue=1 |pages=38–41; quiz 42 |doi=10.4997/JRCPE.2011.110 |pmid=21365066 |doi-access=free}}{{clarify|date=January 2025}}

Treatment requires a firm and transparent diagnosis based on positive features which both health professionals and patients can feel confident about. It is essential that the health professional confirms that this is a common problem which is genuine, not imagined and not a diagnosis of exclusion.{{Cite web|title=Functional Neurological Disorder|url=https://rarediseases.org/rare-diseases/fnd/|access-date=2022-01-20|website=NORD (National Organization for Rare Disorders)|language=en-US}}

A multi-disciplinary approach to treating functional neurological disorder is recommended.

Treatment options can include:

• Medication such as sleeping tablets, painkillers, anti-epileptic medications and anti-depressants (for patients with depression co-morbid or for pain relief)
• Cognitive behavior therapy (CBT) can help a person modify their thought patterns to change emotions, mood, or behavior
• Physiotherapy and occupational therapy

Physiotherapy with someone who understands functional disorders may be the initial treatment of choice for patients with motor symptoms such as weakness, gait (walking) disorder and movement disorders. Nielsen et al. have reviewed the medical literature on physiotherapy for functional motor disorders up to 2012 and concluded that the available studies, although limited, mainly report positive results.{{cite journal | vauthors = Nielsen G, Stone J, Edwards MJ | title = Physiotherapy for functional (psychogenic) motor symptoms: a systematic review | journal = Journal of Psychosomatic Research | volume = 75 | issue = 2 | pages = 93–102 | date = August 2013 | pmid = 23915764 | doi = 10.1016/j.jpsychores.2013.05.006 }}

For many patients with FNSD, accessing treatment can be difficult. Availability of expertise is limited and they may feel that they are being dismissed or told "it's all in your head" especially if psychological input is part of the treatment plan. Some medical professionals are uncomfortable explaining and treating patients with functional symptoms. Changes in the diagnostic criteria, increasing evidence, literature about how to make the diagnosis and how to explain it and changes in medical training is slowly changing this.{{cite journal | vauthors = Edwards MJ | title = Functional neurological symptoms: welcome to the new normal | journal = Practical Neurology | volume = 16 | issue = 1 | pages = 2–3 | date = February 2016 | pmid = 26769760 | doi = 10.1136/practneurol-2015-001310 | s2cid = 29823685 }}

Wessely and White have argued that FNSD may merely be an unexplained somatic symptom disorder.{{cite journal | vauthors = Wessely S, White PD | title = There is only one functional somatic syndrome | journal = The British Journal of Psychiatry | volume = 185 | issue = 2 | pages = 95–96 | date = August 2004 | pmid = 15286058 | doi = 10.1192/bjp.185.2.95 | doi-access = free }} FNSD remains a stigmatized condition in the healthcare setting.{{cite journal | vauthors = Kozlowska K, Sawchuk T, Waugh JL, Helgeland H, Baker J, Scher S, Fobian AD | title = Changing the culture of care for children and adolescents with functional neurological disorder | journal = Epilepsy & Behavior Reports | volume = 16 | pages = 100486 | date = 2021 | pmid = 34761194 | pmc = 8567196 | doi = 10.1016/j.ebr.2021.100486 }}{{cite journal | vauthors = O'Neal MA, Dworetzky BA, Baslet G | title = Functional neurological disorder: Engaging patients in treatment | journal = Epilepsy & Behavior Reports | volume = 16 | pages = 100499 | date = 2021-01-01 | pmid = 34877516 | pmc = 8633865 | doi = 10.1016/j.ebr.2021.100499 }}

Functional neurologic disorder, is a more recent and inclusive term for what is sometimes referred to as conversion disorder.

Throughout its history, many patients have been misdiagnosed with conversion disorder when they had organic disorders such as tumors, epilepsy, or vascular diseases. This has led to patient deaths, a lack of appropriate care and suffering for the patients.{{cite web |title=Sigmund Freud: somatization, medicine and misdiagnosis |url=http://www.richardwebster.net/freudandhysteria.html |url-status=dead |archive-url=https://web.archive.org/web/20040511073728/http://www.richardwebster.net/freudandhysteria.html |archive-date=May 11, 2004 |access-date=2016-02-21 |website=www.richardwebster.net |vauthors=Webster R}}

There is a growing understanding that symptoms are real and distressing, and are caused by an incorrect functioning of the brain rather than being imagined or feigned.{{cite web |title=Functional neurologic disorders/conversion disorder |url=https://www.mayoclinic.org/diseases-conditions/conversion-disorder/symptoms-causes/syc-20355197 |website=Mayo Clinic}}

• Conversion disorder

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• {{cite journal | vauthors = Kwon D | title = A Disorder of Mind and Brain: A mysterious condition once known as hysteria is challenging the divide between psychiatry and neurology | journal = Scientific American | volume = 323 | issue = 5 | date = November 2020 | pages = 58–65 (60) | quote = A variety of conditions that have variously been termed "hysteria", "conversion disorder", or "psychosomatic illness" have most recently been given the name "functional neurological disorder (FND), [which] is deliberately neutral, simply denoting a problem in the functioning of the nervous system }}

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Category:Neurological disorders