Conversion disorder, now formally termed Functional Neurological Symptom Disorder (FND) in DSM-5-TR, is a "rule-in" diagnosis based on positive clinical signs demonstrating incompatibility with recognized neurological disease — it is no longer a diagnosis of exclusion. [1-2] FND is among the most common conditions encountered by neurologists (~16% of new referrals) and causes disability comparable to conditions like multiple sclerosis or epilepsy. [3-4]
1. History
- Onset characteristics: Acute or subacute onset is typical; ask about the exact timing and circumstances of symptom onset [5]
- Precipitating events: Physical injury, surgery, medical illness, or psychological/emotional stressor — though a precipitant is absent in up to 50% of cases and is no longer required for diagnosis [1-2]
- Symptom characterization: Motor (weakness, paralysis, tremor, dystonia, gait abnormality), sensory (numbness, vision/hearing changes), or seizure-like episodes (nonepileptic seizures) [1]
- Temporal pattern: Waxing and waning course, spontaneous remissions, variability across days or within the same encounter [5]
- Associated symptoms: Chronic pain, fatigue, globus sensation, dysphonia, diplopia [1][6]
- Dissociative symptoms: Depersonalization, derealization, dissociative amnesia — particularly at onset or during attacks [1]
- Important negatives: Ask about bowel/bladder incontinence (uncommon in FND seizures), tongue biting (lateral tongue bite suggests epilepsy), postictal confusion (typically absent in functional seizures)
2. Alarm Features
- New focal neurological deficit with acute onset — must rule out stroke before attributing to FND [7-8]
- Symptoms that follow a recognized vascular territory or dermatomal distribution
- Progressive neurological decline or new symptoms in a patient with established FND (FND can coexist with neurological disease such as epilepsy or MS) [1-2]
- Bowel/bladder dysfunction, saddle anesthesia (cauda equina)
- Fever with neurological symptoms (encephalitis, meningitis)
- Papilledema or signs of elevated intracranial pressure
- Status epilepticus — prolonged unresponsiveness requires urgent differentiation from functional seizures
3. Medications
- Medications that can worsen FND: Opiates, benzodiazepines, and other sedatives may perpetuate or worsen symptoms [4]
- No specific pharmacotherapy is established for FND itself [9]
- Treat comorbidities: SSRIs/SNRIs for comorbid depression and anxiety [4]
- Avoid: Antiepileptic drugs for functional (nonepileptic) seizures — a common source of iatrogenic harm
- Avoid: D2-blocking neuroleptics (risk of drug-induced movement disorders outweighs any theoretical benefit) [10]
- Medication review: Discontinue unnecessary medications that were started based on a misdiagnosis (e.g., anticonvulsants for presumed epilepsy)
4. Diet
- No specific dietary triggers or recommendations are established for FND
- General wellness measures apply: adequate hydration, balanced nutrition, regular sleep hygiene
- Patients with comorbid functional GI disorders (e.g., IBS) may benefit from dietary modifications relevant to those conditions [4]
5. Review of Systems
- Neurological: Weakness, numbness, tremor, gait difficulty, seizure-like episodes, vision changes, speech changes, swallowing difficulty
- Psychiatric: Depression, anxiety, PTSD symptoms, panic attacks, dissociative episodes [1][5]
- Pain: Chronic pain, fibromyalgia, headaches [6]
- GI: IBS symptoms (common functional comorbidity) [4]
- GU: Painful bladder syndrome [4]
- Sleep: Insomnia, non-restorative sleep
- Fatigue: Often prominent and disabling [5]
6. Collateral History and Family History
- Collateral: Witness accounts of seizure-like episodes are invaluable — ask about eye closure during events (eyes typically closed in functional seizures vs. open in epileptic seizures), duration, and level of awareness [1]
- Psychosocial context: Ongoing stressors, relationship difficulties, occupational stress, recent losses [5]
- Trauma history: Childhood adversity, sexual/physical abuse, emotional neglect — present in a significant proportion but not universal [3]
- Family history: Neurological disease in family members (may shape illness beliefs), psychiatric disorders, other functional somatic syndromes
- Illness models: Exposure to others with similar symptoms (e.g., family member with epilepsy or stroke) may influence symptom presentation
7. Risk Factors
- Female sex (3:1 female-to-male ratio), though the disorder is commonly underdiagnosed in older men [4][9]
- Young to middle-aged adults most commonly affected [11]
- History of childhood adversity or maltreatment [3]
- Prior physical injury or surgery as precipitant [2][5]
- Comorbid psychiatric disorders: Depression, anxiety, PTSD, personality disorders [5]
- Dissociative tendencies and alexithymia [12]
- Other functional somatic syndromes: IBS, fibromyalgia, chronic fatigue [4]
- Disorganized attachment style [9]
- Prior medical illness or exposure to neurological disease models
8. Differential Diagnosis
- Stroke/TIA — the most critical cannot-miss diagnosis when presenting with acute weakness or sensory loss [7-8]
- Epilepsy — must differentiate from functional (nonepileptic) seizures; can coexist with FND [1]
- Multiple sclerosis — relapsing-remitting course can mimic FND; can also coexist [1]
- Myasthenia gravis — fatigable weakness, but follows specific patterns
- Movement disorders (Parkinson disease, essential tremor, dystonia) — functional tremor/dystonia can closely mimic these [2]
- Malingering — intentional symptom production for external gain; relatively rare [1-2]
- Factitious disorder — intentional symptom production without obvious external reward [1]
- Somatic symptom disorder — excessive thoughts/behaviors related to somatic symptoms, but lacks demonstrable incompatibility with neurological disease [1]
- Panic disorder — episodic neurological symptoms (tremor, paresthesias) but with cardiorespiratory features and retained awareness [1]
- Depressive disorders — generalized heaviness vs. focal weakness of FND [1]
9. Past Medical History
- Prior episodes of FND or other functional somatic symptoms (high recurrence rate)
- History of chronic pain or fibromyalgia [6]
- Previous surgeries or physical injuries (common precipitants) [5]
- Prior psychiatric diagnoses and treatments
- History of unnecessary procedures or investigations based on misdiagnosis [2]
- Comorbid neurological disease (FND can coexist with epilepsy, MS, etc.) [1]
10. Physical Exam
Vital signs: Typically normal
Key positive "rule-in" signs (specificities 64–100%): [5][11]
- Hoover's sign (functional leg weakness): Weakness of hip extension normalizes with contralateral hip flexion against resistance — validated in 5 studies [1][5]
- Hip abductor sign: Weakness of thigh abduction normalizes with contralateral abduction against resistance [1]
- Tremor entrainment test: Functional tremor changes frequency, entrains to, or is suppressed by contralateral rhythmic movements [1-2]
- Whack-a-mole sign: Suppression of involuntary movement in one body part causes re-emergence in another [2]
- Drift without pronation: Arm drifts downward but without pronation (organic lesions cause pronator drift) [2]
- Give-way/collapsing weakness: Initial resistance followed by sudden collapse [13]
- Functional gait: Dragging monoplegic gait, knee buckling, excessive slowness, falling toward support, noneconomic postures [5]
- Functional seizures: Persistent eye closure (often with resistance to opening), bilateral motor movements with preserved awareness, duration >5 minutes, waxing/waning [1]
- Functional dystonia: Fixed inverted ankle, clenched fist, sudden onset, lack of sensory tricks [1][5]
- Sternocleidomastoid test: Inability to rotate head toward the "paralyzed" side [2]
Important caveats: Diagnosis should be based on the overall clinical picture, not a single sign. [1] La belle indifférence is not specific and should not be used diagnostically. [1]
11. Lab Studies
- No specific lab test confirms or excludes FND — labs are used to rule out dangerous mimics
- Basic labs to consider: CBC, BMP, glucose, calcium, magnesium, TSH
- Toxicology screen if altered mental status or seizure-like presentation
- Prolactin level: Modest elevation 15–20 minutes post-event may support generalized tonic-clonic epileptic seizure but is neither sensitive nor specific; not reliable for distinguishing functional from epileptic seizures
- D-dimer, inflammatory markers if concern for stroke or other vascular pathology [8]
- ANA, ESR if autoimmune etiology suspected
12. Imaging
- CT head (emergent): Required acutely to rule out stroke, hemorrhage, or mass lesion when presenting with acute focal deficits [7]
- MRI brain: Consider if clinical suspicion for MS, structural lesion, or other neurological disease; often normal in FND
- CT/MR angiography: If stroke remains on the differential
- Imaging is often unnecessary once positive clinical signs establish FND — avoid excessive imaging that reinforces illness behavior and increases healthcare costs [2][4]
- Pitfall: Do not overinterpret incidental findings (e.g., white matter lesions) as explanatory of symptoms [4]
13. Special Tests
- Video-EEG monitoring: Gold standard for differentiating functional (nonepileptic) seizures from epileptic seizures — captures a typical event with normal ictal EEG [1]
- Electromyography (EMG)/nerve conduction studies: May help exclude neuromuscular disease in cases of weakness
- Bereitschaftspotential (readiness potential): Can be detected before functional jerks on back-averaged EEG, supporting a functional diagnosis [4]
- Clinical neurophysiology: Tremor analysis can demonstrate variable frequency and entrainment [4]
- Diagnostic scoring/clinical signs: No formal scoring system, but the constellation of positive examination signs (Hoover's, entrainment, etc.) with high specificity guides diagnosis [5][14]
14. ECG
- ECG is indicated when the presentation includes syncope-like episodes or unresponsiveness to rule out cardiac arrhythmia
- Functional seizures may mimic syncope — ECG helps exclude long QT, Brugada, or other arrhythmogenic causes
- No specific ECG pattern is associated with FND itself
15. Assessment
- FND is a genuinely experienced, involuntary condition — not feigned — with an emerging neurobiological basis involving altered brain network functioning (hypoactivation of supplementary motor area, disrupted sense of agency) [2][4]
- Severity stratification: Ranges from mild, self-limited episodes to severe, chronic disability comparable to MS or epilepsy [3]
- Typical presentation: Young to middle-aged adult with acute-onset motor or seizure-like symptoms, often following a physical or psychological precipitant, with positive examination signs demonstrating internal inconsistency [2][5]
- Atypical presentations: Older adults, male patients, isolated sensory symptoms, or FND coexisting with true neurological disease [4]
- Complications: Iatrogenic harm from unnecessary medications (e.g., anticonvulsants), procedures, and prolonged diagnostic delays; chronic disability; psychiatric comorbidity worsening [2]
16. Treatment Plan
Diagnosis delivery is the first and most critical therapeutic intervention: [2][15]
- Validate symptoms as real and involuntary
- Explain the diagnosis using positive clinical signs (e.g., demonstrate Hoover's sign to the patient)
- Use the term "functional neurological disorder" — frame as a problem with how the brain is functioning, not structural damage
- Provide written information and direct to resources (e.g., neurosymptoms.org) [4]
Definitive treatment
- Functional motor symptoms: Specialized physiotherapy/rehabilitation is the treatment of choice — goal-directed, incorporating retraining of normal movement patterns [2][11]
- Functional seizures: CBT adapted for nonepileptic seizures has the most evidence [2]
- Combined approach: A recent RCT demonstrated that combined physiotherapy + CBT for functional movement disorders led to 58% of patients rating themselves "much improved" or "very much improved" vs. 5% in the control group [16]
- Psychotherapy: CBT, psychodynamic therapy, and hypnotherapy all have some evidence; psychotherapy is an emerging first-line intervention across FND subtypes [6][9][12]
- Treat comorbidities: Depression, anxiety, PTSD, chronic pain, sleep disorders [4]
- Medication review: Taper opiates, benzodiazepines, unnecessary anticonvulsants [4]
17. Disposition
- Discharge criteria (ED): Dangerous neurological mimics excluded, patient is safe and functionally stable, diagnosis explained, follow-up arranged [13][17]
- Admission criteria: Inability to ambulate or perform ADLs safely, need for video-EEG monitoring, acute safety concerns (suicidality), severe psychiatric comorbidity requiring stabilization
- Observation: Consider for prolonged or recurrent functional seizures to confirm diagnosis and ensure safety
- Specialist consultation triggers:
- Neurology: For diagnostic confirmation, video-EEG, or when coexisting neurological disease is suspected [17]
- Psychiatry: For significant psychiatric comorbidity, suicidality, or psychotherapy coordination [4]
- Rehabilitation medicine/PT/OT: For functional motor symptoms [11]
18. Follow Up / Return Precautions
- Follow-up timing: Neurology and/or psychiatry within 1–2 weeks of initial diagnosis; early follow-up improves outcomes and prevents diagnostic drift [11][13]
- Return precautions:
- New or different neurological symptoms (FND can coexist with organic disease — new symptoms warrant re-evaluation) [2]
- Worsening symptoms despite treatment
- Suicidal ideation or severe psychiatric decompensation
- Prolonged unresponsiveness or injury during events
- Patient counseling:
- Symptoms are real, not imagined or "all in your head"
- Recovery is possible with appropriate treatment — but not all patients respond to currently available therapies [11]
- Avoid reinforcing disability (e.g., unnecessary assistive devices)
- Engage family/support system in understanding the diagnosis [4]
- Expected course: Variable — some patients recover rapidly with proper diagnosis and treatment; others develop chronic symptoms. Prognostic factors for poorer outcomes include longer symptom duration before diagnosis, comorbid personality disorder, and ongoing litigation [5]
References
1. Diagnostic and Statistical Manual of Mental Disorders. — Dilip V. Jeste, Jeffrey A. Lieberman, David Fassler, et al American Psychiatric Association (2022). 2022.
2. Current Concepts in Diagnosis and Treatment of Functional Neurological Disorders. — Espay AJ, Aybek S, Carson A, et al. JAMA Neurology. 2018.
3. Stressful Life Events and Maltreatment in Conversion (Functional Neurological) Disorder: Systematic Review and Meta-Analysis of Case-Control Studies. — Ludwig L, Pasman JA, Nicholson T, et al. The Lancet. Psychiatry. 2018.
4. Functional Neurological Disorder: New Subtypes and Shared Mechanisms. — Hallett M, Aybek S, Dworetzky BA, et al. The Lancet. Neurology. 2022.
5. A Review and Expert Opinion on the Neuropsychiatric Assessment of Motor Functional Neurological Disorders. — Perez DL, Aybek S, Popkirov S, et al. The Journal of Neuropsychiatry and Clinical Neurosciences. 2020.
6. Conversion Disorder, Functional Neurological Symptom Disorder, and Chronic Pain: Comorbidity, Assessment, and Treatment. — Tsui P, Deptula A, Yuan DY. Current Pain and Headache Reports. 2017.
7. Established Treatments for Acute Ischaemic Stroke. — Khaja AM, Grotta JC. Lancet. 2007.
8. Differentiating Cerebral Ischemia From Functional Neurological Symptom Disorder: A Psychosomatic Perspective. — Scheidt CE, Baumann K, Katzev M, et al. BMC Psychiatry. 2014.
9. Psychosocial Interventions for Conversion and Dissociative Disorders in Adults. — Ganslev CA, Storebø OJ, Callesen HE, Ruddy R, Søgaard U. The Cochrane Database of Systematic Reviews. 2020.
10. Psychogenic Movement Disorders. — Hinson VK, Haren WB. The Lancet. Neurology. 2006.
11. Diagnosis and Management of Functional Neurological Disorder. — Aybek S, Perez DL. BMJ. 2022.
12. Psychotherapy for Functional Neurological (Conversion) Disorder: A Case Bridging Mind, Brain, and Body. — Godena EJ, Perez DL, Crain LD, et al. The Journal of Clinical Psychiatry. 2021.
13. Functional Neurological Disorders: Acute Presentations and Management. — Cock HR, Edwards MJ. Clinical Medicine. 2018.
14. A Practical Guide to Assessing Functional Motor Weakness: A Review of Validated Techniques. — Dolbow J, El-Azzouni S, Zhang Y, Geiger C. Journal of Neurology. 2025.
15. Conversion Disorders: Psychiatric and Psychotherapeutic Aspects. — Cottencin O. Neurophysiologie Clinique = Clinical Neurophysiology. 2014.
16. Combined Physiotherapy and Cognitive Behavioral Therapy for Functional Movement Disorders: A Randomized Clinical Trial. — Macías-García D, Méndez-Del Barrio M, Canal-Rivero M, et al. JAMA Neurology. 2024.
17. Functional Neurological Disorder in the Emergency Department. — Finkelstein SA, Cortel-LeBlanc MA, Cortel-LeBlanc A, Stone J. Academic Emergency Medicine : Official Journal of the Society for Academic Emergency Medicine. 2021.