Psych · General adult psychiatry
Functional neurological symptom disorder (conversion)
Also known as Functional neurological disorder · FND · FNSD · Conversion disorder · Functional neurological symptom disorder · Dissociative neurological symptom disorder · Functional seizures · Dissociative seizures · PNES · Functional movement disorder
Exam-exhaustive fellowship reference on functional neurological symptom disorder (conversion/FND) — DSM-5-TR and ICD-11 nosology, positive rule-in signs, predictive processing and agency models, FND clinic pathways, specialist physiotherapy, CBT for functional seizures (CODES/LaFrance), pejorative-language avoidance, prognosis, and exam discriminators. FRANZCP-primary, globally tagged.
Practise this topic
On this page
Study tools
Your progress
Saved on this device.
Target exams
Red flags
- Acute lateralising weakness or speech change that could be stroke — complete stroke pathway first; positive FND signs do not cancel emergency work-up when indicated
- First or atypical seizure-like events without established functional diagnosis — protect airway, time the event, and do not assume PNES until epilepsy is adequately considered
- Rapidly progressive neurology, fever, encephalopathy, or catatonic features — rethink autoimmune encephalitis and medical differentials
- Pejorative labelling ('faking', 'hysterical', dismissive 'pseudo') — iatrogenic harm and care disengagement
- Leaving a patient on escalating antiepileptic polypharmacy after a clear video-EEG diagnosis of functional seizures alone
- Assuming malingering without clear evidence of intentional symptom production
- Missing dual pathology (FND plus MS, epilepsy, or structural disease)
Meet the patient
A 26-year-old warehouse worker is admitted overnight with a "paralysed" right leg. A pallet brushed his lower back yesterday; the leg gave way and has not moved since. MRI of brain and spine: normal. The night intern has written "query conversion, attention-seeking?" in the notes. On the ward round you ask him to push his good hip up against your hand — and the "paralysed" leg presses firmly down into the bed.[5][6]
That is Hoover's sign, and it changes the next conversation completely. The intern's question — "is he faking?" — is the wrong question. The examiner's question — "what positive sign makes this diagnosis, and what exactly do you say to the patient?" — is this topic.[1][4][5]
References19ShowHide
- [1]Espay AJ, Aybek S, Carson A, et al. Current Concepts in Diagnosis and Treatment of Functional Neurological Disorders JAMA Neurol, 2018.PMID 29868890
- [2]Hallett M, Aybek S, Dworetzky BA, et al. Functional neurological disorder: new subtypes and shared mechanisms Lancet Neurol, 2022.PMID 35430029
- [3]Aybek S, Perez DL Diagnosis and management of functional neurological disorder BMJ, 2022.PMID 35074803
- [4]Stone J, Burton C, Carson A Recognising and explaining functional neurological disorder BMJ, 2020.PMID 33087335
- [5]Daum C, Hubschmid M, Aybek S The value of 'positive' clinical signs for weakness, sensory and gait disorders in conversion disorder: a systematic and narrative review J Neurol Neurosurg Psychiatry, 2014.PMID 23467417
- [6]Daum C, Gheorghita F, Spatola M, et al. Interobserver agreement and validity of bedside 'positive signs' for functional weakness, sensory and gait disorders in conversion disorder: a pilot study J Neurol Neurosurg Psychiatry, 2015.PMID 24994927
- [7]Edwards MJ, Adams RA, Brown H, Pareés I, Friston KJ A Bayesian account of 'hysteria' Brain, 2012.PMID 22641838
- [8]Maurer CW, LaFaver K, Ameli R, et al. Impaired self-agency in functional movement disorders: A resting-state fMRI study Neurology, 2016.PMID 27385746
- [9]Stone J, Carson A, Duncan R, et al. Symptoms 'unexplained by organic disease' in 1144 new neurology out-patients: how often does the diagnosis change at follow-up? Brain, 2009.PMID 19737842
- [10]Carson A, Stone J, Hibberd C, et al. Disability, distress and unemployment in neurology outpatients with symptoms 'unexplained by organic disease' J Neurol Neurosurg Psychiatry, 2011.PMID 21257981
- [11]Carson A, Lehn A Epidemiology Handb Clin Neurol, 2016.PMID 27719864
- [12]Ludwig L, Pasman JA, Nicholson T, et al. Stressful life events and maltreatment in conversion (functional neurological) disorder: systematic review and meta-analysis of case-control studies Lancet Psychiatry, 2018.PMID 29526521
- [13]Nielsen G, Stone J, Matthews A, et al. Physiotherapy for functional motor disorders: a consensus recommendation J Neurol Neurosurg Psychiatry, 2015.PMID 25433033
- [14]Nielsen G, Stone J, Lee TC, et al. Specialist physiotherapy for functional motor disorder in England and Scotland (Physio4FMD): a pragmatic, multicentre, phase 3 randomised controlled trial Lancet Neurol, 2024.PMID 38768621
- [15]LaFrance WC Jr, Baird GL, Barry JJ, et al. Multicenter pilot treatment trial for psychogenic nonepileptic seizures: a randomized clinical trial JAMA Psychiatry, 2014.PMID 24989152
- [16]Goldstein LH, Robinson EJ, Mellers JDC, et al. Cognitive behavioural therapy for adults with dissociative seizures (CODES): a pragmatic, multicentre, randomised controlled trial Lancet Psychiatry, 2020.PMID 32445688
- [17]Gelauff J, Stone J Prognosis of functional neurologic disorders Handb Clin Neurol, 2016.PMID 27719869
- [18]Gelauff JM, Carson A, Ludwig L, Tijssen MAJ, Stone J The prognosis of functional limb weakness: a 14-year case-control study Brain, 2019.PMID 31167232
- [19]Bennett K, Diamond C, Hoeritzauer I, et al. A practical review of functional neurological disorder (FND) for the general physician Clin Med (Lond), 2021.PMID 33479065