NICE vs SIGN: Management of Functional Neurological Disorder (2025) - A Clinical Comparison
This guide provides a detailed, factual comparison of the 2025 National Institute for Health and Care Excellence (NICE) guideline (NG 244) and the Scottish Intercollegiate Guidelines Network (SIGN) guideline (SIGN 169) for the management of Functional Neurological Disorder (FND) in adults. Both guidelines represent a significant step forward in standardising care for this complex condition. While their core principles are aligned, there are nuanced differences in structure, emphasis, and practical application that clinicians should be aware of.
See how this translates to practice: Explore our Clinical governance features, visit the Patient Safety Hub, or review Clinical Safety & Assurance for enterprise rollout.
Diagnosis and Assessment
Both guidelines strongly emphasise the importance of a positive diagnosis based on positive clinical signs ("rule-in" criteria), moving away from a diagnosis of exclusion. The presence of inconsistency or incongruity with recognised neurological disease is central to both.
NICE (NG 244)
- Diagnostic Terminology: Recommends using the term "Functional Neurological Disorder" consistently.
- Communication: Provides a very structured framework for explaining the diagnosis. This includes:
- Validating the patient's symptoms as real and common.
- Using simple explanatory models (e.g., a "software problem" vs. "hardware problem" in the nervous system).
- Explicitly stating that FND is not a sign of feigning or malingering.
- Assessment: Stresses a comprehensive biopsychosocial assessment to identify predisposing, precipitating, and perpetuating factors.
SIGN (SIGN 169)
- Diagnostic Terminology: Acknowledges "Functional Neurological Disorder" as the preferred term but provides more detailed discussion on historical terms (e.g., conversion disorder, dissociative neurological symptoms) and their place in ICD-10/11, which can be helpful for liaison psychiatry.
- Communication: Also prioritises clear communication but places a stronger emphasis on the immediate involvement of a mental health professional in the diagnostic feedback session if possible, particularly for complex presentations.
- Assessment: Includes more specific recommendations for the use of neuropsychology in assessment, particularly for evaluating cognitive symptoms within FND.
Key Difference: NICE offers a more prescriptive, patient-facing communication script. SIGN provides greater detail on diagnostic classification and the role of neuropsychology in assessment.
Treatment and Management
Both guidelines advocate for a multidisciplinary, collaborative approach, with physiotherapy and psychology as first-line treatments.
NICE (NG 244)
- Physiotherapy: Recommends a course of specialist physiotherapy focused on movement retraining, attention strategies, and functional goals. It explicitly advises against therapies that are purely compensatory.
- Psychological Therapy: Recommends considering a course of cognitive behavioural therapy (CBT) or other NICE-recommended psychological therapies for common mental health problems, tailored to the FND presentation.
- Pharmacology: Advises against using medication specifically to treat FND symptoms. Medications should only be used to treat co-morbid conditions (e.g., anxiety, depression, pain).
- Service Structure: Strongly recommends establishing designated FND clinics or pathways within neurology services to coordinate care.
SIGN (SIGN 169)
- Physiotherapy: Similarly recommends specialist, impairment-based physiotherapy. It provides more detailed examples of specific techniques, such as using distraction or altered attentional focus during movement.
- Psychological Therapy: While also endorsing CBT, SIGN gives more weight to other modalities, such as psychodynamic therapy and mindfulness-based approaches, based on a broader review of the evidence, particularly for patients with significant trauma histories.
- Pharmacology: Aligns with NICE but includes a specific recommendation to review and rationalise existing medications that may be contributing to symptoms (e.g., sedatives).
- Service Structure: Emphasises the "hub and spoke" model, where specialist tertiary centres (hubs) support local services (spokes) through training and consultation.
Key Difference: NICE is more prescriptive in recommending CBT, reflecting its standard methodology. SIGN presents a broader range of psychological therapies as viable options. Both strongly advocate for specialised physiotherapy.
Special Situations and Comorbidities
Both Guidelines Cover:
- Pain and Fatigue: Management of co-morbid chronic pain and fatigue should be integrated into the FND treatment plan.
- Acute Presentations: Recommendations for managing functional symptoms in emergency and acute settings.
NICE Specifics:
- Children and Young People: Includes a separate section with recommendations tailored to this population, a notable expansion from previous guidance.
SIGN Specifics:
- Cognitive Symptoms: Provides more detailed guidance on the assessment and management of functional cognitive disorders (e.g., dissociative amnesia).
- Severe and Complex Cases: Includes specific recommendations for in-patient multidisciplinary rehabilitation for patients with severe disability who have not responded to community-based treatment.
Key Difference: NICE includes specific guidance for children and young people. SIGN offers more depth on functional cognitive symptoms and in-patient rehabilitation pathways.
Practical Clinical Flow: A Synthesis
- Presentation & Suspicion: Patient presents with neurological symptoms that are inconsistent or incongruent.
- Positive Diagnosis: Neurologist (or other specialist) makes a positive diagnosis using "rule-in" signs. Investigations are used to exclude other pathology only if clinically indicated, not to diagnose FND.
- Diagnostic Explanation: The diagnosis is explained clearly and empathetically, using the principles from either guideline. SIGN may involve a mental health professional at this stage more routinely.
- Biospychosocial Assessment: Comprehensive assessment to understand the individual's context and co-morbidities.
- Multidisciplinary Care Planning: The core team (neurology, psychiatry/psychology, physiotherapy) agrees on a treatment plan with the patient.
- Motor Symptoms: Refer to specialist FND physiotherapy.
- Psychological Factors: Refer for psychological therapy (CBT per NICE; a broader range per SIGN).
- Co-ordination & Review: A named professional (often in a designated clinic or pathway) coordinates care and schedules regular reviews to monitor progress and adjust the plan.
- Managing Complexity: For severe, treatment-resistant cases, consider referral to a specialised in-patient rehabilitation service (stronger emphasis in SIGN).
Frequently Asked Questions (FAQs) for Clinicians
1. Which guideline should I follow in Scotland/Wales/England/Northern Ireland?
Answer: SIGN is the standard for Scotland. NICE is the standard for England, Wales, and Northern Ireland. However, the guidelines are highly complementary. Clinicians everywhere can benefit from consulting both, as SIGN often provides more detailed practical considerations for complex cases, while NICE offers a very clear, structured framework for diagnosis and communication.
2. What is the single most important takeaway from both guidelines?
Answer: The paradigm shift to a positive, "rule-in" diagnosis based on clinical signs, communicated early and effectively, is the cornerstone of modern FND management. Abandoning the concept of a "diagnosis of exclusion" improves patient trust and engagement.
3. How do I handle a patient who rejects the diagnosis?
Answer: Both guidelines advise against confrontation. Focus on building rapport, validating the distress of the symptoms, and framing treatment as a way to improve function and control over the symptoms, rather than debating the diagnosis itself. A phased approach, starting with physiotherapy which can feel more tangible to some patients, is often helpful.
4. Are there any drug treatments for FND?
Answer: No. Both guidelines are clear that there is no pharmacological treatment for the core symptoms of FND. Medication should only be used to treat co-morbid conditions like depression, anxiety, or sleep disturbance, and existing medications should be reviewed for potential iatrogenic effects.
5. What is the role of the GP in ongoing management?
Answer: The GP is crucial as the longitudinal care coordinator. They provide continuity, manage co-morbidities, support the patient between specialist appointments, and help prevent unnecessary further referrals or investigations, acting as a "gatekeeper" for stability.
Source Links
- NICE Guideline NG244 (2025): Functional neurological disorder: assessment and management
- SIGN Guideline SIGN 169 (2025): Management of Functional Neurological Disorder