BJPsych Advances (2019), vol. 25, 342–350 doi: 10.1192/bja.2019.38 ARTICLE Functional cognitive disorders: identification and management Norman A. Poole, Sarah R. Cope, Cate Bailey & Jeremy D. Isaacs Norman Poole, MBChB, MRCPsych, Other follow-up studies have demonstrated similar SUMMARY MSc, MD(Res), is a consultant rates of stability, with low rates of progression to neuropsychiatrist at St George’s We review the various functional cognitive disor- neurodegenerative disorders (Vestberg 2010). In a Hospital in south London and editor ders (FCDs) – complaints about memory function large study of cognitively well older people, it was of the BJPsych Bulletin. His special or another cognitive process in the absence of interests are functional neurological reduced awareness of memory impairment that pre- relevant neuropathology. These are increasingly disorder, the neuropsychiatry of dicted near-term onset of dementia (Wilson et al movement disorders and psycho- coming to the attention of psychiatrists and neurol- pathology generally. Sarah Cope, ogists and FCD encompasses some newly recog- 2015). Indeed, there is only a small association DClinPsy, MSc, BSc(Hons), is a clin- nised conditions in addition to classic types such between subjective report and objective cognitive ical psychologist working in the as pseudodementia and psychogenic amnesia. performance, and it is weaker than the link Neuropsychiatry Service at St The clinical features, neuropsychological findings between subjective report and affect (Burmester ’ George s Hospital, London. Her and treatment are presented and discussed. research interests centre around the 2016). Given that other functional neurological dis- psychological treatment of functional orders can be comorbid with an underlying neurode- LEARNING OBJECTIVES neurological disorder. Cate Bailey, generative condition – so-called functional overlay – MBBS, MRCPsych, MRes, is a spe- After reading this article you will be able to: it would not be surprising for an FCD to occur in the cialist registrar in general adult and • describe clinical features of FCD and how it dif- context of prodromal dementia or, increasingly, for old age psychiatry and a former aca- fers from neurodegenerative causes of cogni- it to be triggered by the identification of dementia demic clinical fellow in old age tive impairment psychiatry at Queen Mary University, • be able to subclassify cases of FCD using the biomarkers such as being positive for APOE. In London. She is an honorary clinical the absence of relevant evidence, this remains a research fellow at Queen Mary proposed nosology University of London. Her previous • understand how to discuss the diagnosis with conjecture. research has focused on communi- the patient and explain how the symptoms arise. With the expansion of diagnostic memory clinics cation of dementia diagnoses and over the past decade, increasing numbers of people assessment of functional memory DECLARATION OF INTEREST with FCD are being identified, which reflects greater disorders. Jeremy Isaacs, MA, None. MBBS, PhD, MRCP, is a consultant numbers of patients attending without neurodegen- neurologist at St George’s Hospital, erative conditions (Larner 2014). According to KEYWORDS London, and Kingston Hospital, studies in the UK and the USA, between 33 and Kingston upon Thames, and an hon- Clinical neurology; cognitive neuroscience; dis- 56% of persons assessed in memory clinics are diag- orary senior lecturer at St George’s sociative disorders; functional cognitive disorders. University of London. His current nosed as ‘normal’ or ‘no cognitive disorder’ research interests are in functional (Pennington 2015). It is as yet unclear how to con- cognitive disorders, delirium and ceptualise and manage this group of patients. Most clinical trials in Alzheimer’s disease and vascular dementia. Functional cognitive disorder (FCD) denotes a com- are discharged back to primary care without a Correspondence Dr Norman plaint about memory function or, less commonly, diagnosis or are given the placeholder label of mild A. Poole, Department of another cognitive process in the absence of relevant cognitive impairment (MCI), which, we should Neuropsychiatry, South West London ’ neuropathology and with evidence of inconsistency emphasise, is not a synonym for FCD. Although evi- & St George s Mental Health fi NHS Trust, St George’s Hospital, between symptoms reported and signs identi ed at dence-based interventions for the disorder are Blackshaw Road, London assessment. The prototypical FCDs are dissociative lacking, there are some findings to suggest that SW17 0QT, UK. fugue and amnesia, but these account for only a strategies that focus on expectations, cognitive Email: [email protected] tiny proportion of people presenting with subjective restructuring or psychoeducation may be helpful First received 26 Feb 2019 cognitive complaints. The relationship between such (Metternich 2010; Bhome 2018). However, such Final revision 17 Apr 2019 subjective complaints and current or future demen- interventions are generally not available in diagnos- Accepted 29 Apr 2019 tia is complex. A meta-analysis found that older tic memory clinics: 73% of memory service psychia- people (with a mean age of 71.6 years) with subject- trists surveyed in the UK in 2015 discharged Copyright and usage © The Royal College of Psychiatrists ive memory complaints are twice as likely to develop patients with functional disorders of memory to 2019 dementia as those without SMCs over an average primary care and among those who did offer treat- follow-up period of nearly 5 years (Mitchell 2014). ment for FCD there was no agreement on what was A podcast is available to accompany this article at: soundcloud.com/ However, a more recent 6-year follow-up study of appropriate (Bailey 2017). Here, we provide an up bjpsych/bja-2019-38 subjective memory complaints in 81 younger to date summary of research into the nosology, diag- patients (the mean age was 61 years) found that nostic criteria, aetiology, causal mechanisms and 86% were stable or improved (Hessen 2017). management of this emerging clinical conundrum. 342 BJPsych Advances (2019), vol. 25, 342–350 doi: 10.1192/bja.2019.38 Downloaded from https://www.cambridge.org/core. 29 Sep 2021 at 17:17:41, subject to the Cambridge Core terms of use. Functional cognitive disorders Nosology An addition to this list might be the recently Before discussing a proposed nosology for FCD it is described behavioural-variant frontotemporal worthwhile noting the multitude of terms used by dementia (bvFTD) phenocopy syndrome. This syn- cognitive neurologists and psychiatrists to describe drome presents with the clinical symptoms and the condition. Examples of these are listed in Box 1. signs of bvFTD but structural and functional Some terms seem to minimise and normalise the imaging are normal (Kipps 2009) and there is an state, whereas others posit an underlying cause. The absence of progression, even up to 21 years after condition is not well captured in ICD-10 (World diagnosis (Devenney 2018). While it is increasingly Health Organization 1992), which largely empha- accepted that this is not a neurodegenerative condi- sises dissociative fugue and amnesia to the exclusion tion, it is unclear exactly where this disorder sits in of other forms of the disorder. DSM-5 (American our nosology and it likely arises through a mechan- Psychiatric Association 2013) distinguishes between ism distinct from the functional cognitive disorders. dissociative amnesia and other functional neuro- logical disorders, which would include some of the Category 1: memory symptoms in the context of categories described below. DSM-5 has now anxiety/depression removed the need for a prior trauma or stressor Memory symptoms and difficulty with concentration from the diagnostic criteria, given that this is not are commonly reported in anxiety and depression always found and emphasises inconsistency between and are part of the diagnostic criteria. There is a presentation and signs elicited on examination. recall bias such that positive memories are less Given this lack of order, Stone et al (2015) pro- readily accessed, and subtle deficits of attention posed a nosology of FCD. They described six over- and executive functioning are found on neuro- lapping categories: psychological testing: impaired set-shifting and verbal fluency are the most common findings 1 memory symptoms in the context of anxiety/ (Rock 2014). A systematic review conducted by depression Hasselbalch et al (2011) demonstrated that the 2 normal memory lapses that become a focus of executive and attentional dysfunction persists after concern to the patient remission of the depressed mood, leading the 3 isolated functional memory complaints that go review authors to argue that cognitive impairment beyond normal lapses but cannot be accounted is an intrinsic component of depression and not for by anxiety/depression merely an epiphenomenon. Indeed, cognitive dys- 4 hypochondriacal disorder with dementia as the function may adversely affect occupational perform- focus ance more than the depressed mood (McIntyre 5 memory symptoms in the context of another func- 2015). Drug manufacturers have identified this too tional disorder and recent studies of the antidepressant vortioxetine 6 retrograde dissociative ‘psychogenic’ amnesia. suggest that the drug significantly improves cogni- tive functioning across a range of domains compared with placebo and citalopram, independent of its impact on mood (McIntyre