Functional Cognitive Disorder: What causes it and how can you distinguish it from mTBI and malingering?

A new study published in Acta Neurologica Belgica [1] looks at Functional Cognitive Disorder (FCD) and why people with this condition often report problems with memory and cognition even though testing shows their brain is working normally.

What is Functional Cognitive Disorder? 

Functional Cognitive Disorder (FCD) is when someone feels they have issues with memory or concentration, but diagnostic testing and imagery fail to show any organic damage or disease. This can be confusing for those handling claims where FCD is suspected or alleged, because the symptoms are presented as genuine, yet the evidence doesn’t match.

What did the study find? 

One long standing hypothesis is that FCD is caused by an alteration in metacognition. This is essentially how well people understand and judge their own thinking and memory. The authors of the study therefore looked at two types: 

• Global metacognition – how people rate their overall ability to think and remember.
• Local metacognition – how confident they feel about answers on individual tasks.

The study found that people with FCD are poor at judging their overall ability (global metacognition is impaired), however they are quite accurate when judging individual tasks (local metacognition is normal).

This may explain why someone might feel they have poor cognition and memory, even though their test results are normal. It is not that they have a genuinely poor memory, it’s that their self-monitoring system is off.

What causes Functional Cognitive Disorder?

Functional Cognitive Disorder often develops after stressful life events or psychological trauma, including:

• Emotional trauma: Bereavement, relationship breakdown, or exposure to highly stressful events.
• Medical trauma: Surgery, prolonged hospital stays, or serious illness - even when recovery is complete.
• Physical trauma: Mild head injuries, whiplash, or falls where scans show no lasting damage.

These experiences can heighten anxiety and self-focus, leading people to monitor their thinking excessively. Over time, this can create persistent symptoms even when the brain is structurally normal.

Causation challenges

When a claimant alleges Functional Cognitive Disorder (FCD) following an accident, causation becomes complex. Why? 

• Symptoms may appear weeks or months later, complicating the timeline.
• There is no structural brain injury, meaning insurers must rely on expert opinion from those experienced in this field.
• Pre-existing vulnerabilities (such as anxiety or previous trauma) play a role, raising questions about whether the accident was the true cause.
• Overlap with symptoms often found in mild traumatic brain injury (mTBI) can confuse matters - especially if they mimic concussion.

For insurers, this means careful investigation and expert input are essential to determine whether the accident genuinely triggered FCD, whether there was pre-existing vulnerability for FCD and it would have occurred at some point in any event, and/or if FCD was already present. 

Most cases of genuine FCD present incorrectly as mTBI, so it is important to distinguish FCD at an early stage to avoid misdiagnosis. Early therapeutic intervention aimed at helping claimants rebuild confidence in their thinking (metacognitive therapy) is then key. 

Checklist for Insurers when Functional Cognitive Disorder is suspected

1. Forensically analyse the records - pre and post-accident records will help build a picture as to causation. Records should also be analysed to establish whether there is evidence of any other issues which may explain the symptoms. For example, there is an overlap between symptoms of FCD and Alzheimer's disease. 

2. Instruct the right experts – those familiar with functional disorders and metacognition, not just standard cognitive testing.

3. Avoid repeated imaging or unnecessary scans – These rarely change the outcome and add cost.
4. Consider psychological interventions early – Cognitive Behavioural Therapy (CBT) or metacognitive therapy can help address the underlying issue.
5. Ensure the treating rehabilitation team are experienced – it is important the team are experienced in functional disorders and can clearly explain to the claimant that symptoms are caused by how the brain monitors itself, not by brain damage or injury.
6. Review rehabilitation plans – Focus on confidence-building and coping strategies, rather than therapies traditionally targeted at those with mTBI.

Functional Cognitive Disorder and its overlap with malingering 

One of the biggest challenges for insurers is distinguishing genuine Functional Cognitive Disorder (FCD) from malingering.  

Key points to note for insurers are: 

• Genuine FCD symptoms are real and distressing, even though they lack an organic cause. Patients with genuine FCD truly believe they have cognitive problems.
• Malingering involves conscious exaggeration for financial or legal gain, whereas genuine FCD is driven by altered self-monitoring and anxiety.
• Red flags for malingering include inconsistent effort on testing, clear secondary gain, and discrepancies between reported symptoms and observed functioning.
• Specialist neuropsychological testing can help to differentiate the two. FCD patients often show normal performance but poor global self-appraisal, while malingerers may show patterns of intentional underperformance.

For insurers, this means:

• Avoid assuming fraud when imaging is normal.
• Use experienced neuropsychologists who understand functional disorders.
• Document objective evidence and behavioural observations carefully.

Takeaway for Insurers

Recognising Functional Cognitive Disorder as a problem of self-appraisal, not brain injury, can lead to: 

• Clearer prognosis
• Fewer unnecessary investigations
• Better rehabilitation planning
• Better outcomes for claimants
• Lower costs for insurers

At Clyde & Co, our Brain Injury Subject Matter Group (SMG) continually monitors emerging research and developments in neurorehabilitation, neuroscience, and brain-injury claims. We’re committed to providing our clients with clear, practical insights on the issues that matter. If you’d like to explore more of our thought leadership on brain injury, you can find our full library of articles and updates here.

Sources 

1. Metacognitive performance in Functional Cognitive Disorder (FCD): A meta-analysis | Springer Nature Link (2025)