A Strategic Approach to Defending FND Claims

Functional Neurological Disorder (FND) claims are becoming increasingly prevalent in road traffic accident (RTA) litigation, presenting a unique challenge for insurers. FND was traditionally considered to have a psychological origin. However, with recent advancements in brain mechanics and theoretical understanding, there has been a shift towards describing it in more physical terms. FND has both physical and psychological elements and a bio psychosocial framework is the norm and is currently best considered as a disorder of brain processing. This makes it difficult to objectively verify the severity and legitimacy of a claim, often leading to exaggerated or opportunistic claims.

Successfully challenging FND claims requires a multi-faceted approach that combines early investigation, medical scrutiny, causation arguments, surveillance, multi-discipline expert evidence and strategic litigation tactics. The subjective nature of FND symptoms necessitates a robust strategy to differentiate between genuine cases and those where symptoms may be psychosomatic, exaggerated or entirely feigned.

This Rise of FND in Litigation: A Gateway to Exaggerated Claims?

FND is often cited by claimants who report severe, long-term disability following relatively minor road traffic accidents. The absence of identifiable organic damage means that traditional diagnostic tools such as conventional MRI and CT scans may show no abnormalities. Functional brain scans (fMRI) are starting to provide early evidence of why the nervous system and brain goes wrong in FND and a SPECT scan may demonstrate abnormality but often the diagnosis is reliant on clinical assessment.

From a legal standpoint, this creates a credibility gap:

• Claimant may report disabling symptoms without objective medical evidence to support them.

• The symptoms often fluctuate in severity, making them difficult to verify.

• FND can persist for years without a clear prognosis, leading to inflated damages claim.

Furthermore, because FND is often triggered by psychological stress, claimants frequently attempt to link their symptoms directly to the trauma of the accident, even when the collision itself was minor. This raises critical causation concerns, as the Defence team must challenge whether the symptoms stemmed from the accident or from pre-existing psychological vulnerabilities. 

Challenging Medical Evidence and Causation

A. Scrutinising the Medical Diagnosis

Defending an FND claim requires careful cross-examination of the medical evidence. The following areas should be explored:

Was the diagnosis made by a neurologist with expertise in FND? Some claimants are diagnosed by general practitioners or psychologists rather than specialists, undermining the reliability of the diagnosis. Were positive clinical signs of FND identified? Proper FND diagnosis requires clinical signs such as Hoover’s sign or entrainment tests, rather than mere exclusion of other conditions. Is there evidence of symptom exaggeration or malingering? Some claimants may display inconsistencies in their reported symptoms versus observed behaviour. 

Where medical reports lack objective confirmation of FND using established diagnostic criteria, the defence team should instruct their own experts to challenge the diagnosis.

B. Establishing Pre-Existing Psychological Vulnerability

One of the strongest causation challenges in FND cases is demonstrating pre-existing psychological predisposition. Many claimants with FND have a history of depression, anxiety, PTSD, psychosis, dysfunctional relationships or previous functional symptoms. The defence team should obtain:

• Medical records (including psychiatric history) to show pre-existing vulnerabilities.

• Employment history to determine whether psychological stressors existed before the accident.

• Social media evidence to assess whether the claimant displayed normal functioning post-accident.

If pre-existing psychological factors are present, it is open to the defence team to argue that the accident was merely a trigger for an underlying condition, rather than the cause of the disorder itself.

C. Low-Impact Collisions and FND Claims

In minor RTA cases, the defence team should emphasize that the mechanism of injury does not support significant trauma.

Expert biomechanical evidence can: 

• Show that the forces involved were insufficient to cause significant neurological dysfunction.

• Challenge the credibility of claims where FND symptoms manifest immediately after low-impact collisions, which contradicts medical literature on the condition's typical onset.

Using Surveillance and Social Media to Expose Inconsistencies

Given the fluctuating nature of FND symptoms, covert surveillance can be a highly effective tool in identifying discrepancies between a claimant’s reported disability and their actual daily activities. In recent case law, courts have dismissed claims where surveillance evidence contradicted medical reports.

Similarly, social media analysis can reveal: 

• Claimants engaging in physical activities inconsistent with their alleged limitations.

• Evidence of normal social interactions and travel, undermining claims of severe disability.

• Contradictory statements about their condition.

Where surveillance or social media evidence is compelling, defendants should consider the merits of advancing fundamental dishonesty arguments under Section 57 of the Criminal Justice and Courts Act 2015, which could result in claim dismissal and cost recovery.

Expert Witness Selection: A Key Battlefield

The selection of expert witnesses is critical in FND claims. The defence team should instruct:

• A neurologist with FND expertise to diagnose positive physical signs and to give an opinion as to whether there may be an alternative diagnosis / causal mechanism.

• A psychiatrist to evaluate alternative explanations for the claimant’s symptoms. 

• A neuropsychiatrist is essential in confirming an FND diagnosis, distinguishing genuine cases from exaggerated or opportunistic claims, and guiding appropriate treatment strategies.

• A Neuropsychologist to assess cognitive function by conducting neuropsychological testing to evaluate cognitive function, attention, memory and executive functioning.  

• A biomechanical expert to assess whether the forces involved in the accident could plausibly cause neurological dysfunction. 

Cross-examining the claimant’s experts on diagnostic accuracy, alternative causation theories, and inconsistencies in symptom reporting can significantly weaken the claimant’s case.

Litigation Strategy: When to Settle vs. When to Fight

While some FND claims may be genuine, many are exaggerated or opportunistic. Defendants must weigh the costs of litigation against the potential savings from challenging high-value claims.

When to Settle: 

• If medical evidence supports a clear link between the accident and FND.

• If surveillance or social media investigations fail to uncover contradictions.

• If a claimant demonstrates consistent and well-documented symptoms over time.

When to Fight:

• If causation is questionable, especially in low-speed or minor accidents. 

• If medical evidence is weak or inconsistent.

• If there is strong surveillance or social media evidence contradicting the claim.

• If there is a history of pre-existing psychological issues that could explain the symptoms.

A well-timed Part 36 offer at an early stage can put financial pressure on claimants, particularly those relying on litigation funding, while an aggressive stance on fundamental dishonesty can deter fraudulent claims.

Conclusion: A Robust Defence Is Essential

FND claims arising from RTAs present significant challenges due to their subjective nature, but they are not immune to scrutiny. Defendants must adopt a rigorous, evidence-based approach, leveraging medical experts, surveillance, and causation arguments to differentiate legitimate claims from opportunistic ones.

With courts increasingly willing to dismiss exaggerated or fraudulent claims, insurers and defence teams must be proactive in challenging weak FND cases. A strategic, well-documented defence can not only limit liability but also set a precedent that discourages future speculative claims.