Correspondence: Inaccurate reference leads to tripling of reported FND prevalence

Highlights:

  • Perez et al asserted that FND is the “2nd most common” diagnosis in outpatient neurology.
  • Stone et al (2010), cited by Perez et al, does not support the “2nd most common” claim.
  • In Stone et al, a broad “functional/psychological” category was the second most common
  • FND is not synonymous with the “functional/psychological” category in Stone et al.

To the editor:

An article in NeuroImage: Clinical“Neuroimaging in functional neurological disorder: state of the field and research agenda” (Perez et al., 2021), cited a prominent paper (Stone et al., 2010) as evidence for the assertion that functional neurological disorder (FND) is the “2nd most common outpatient neurologic diagnosis.” Although studies have yielded varying FND prevalence rates, the claim that it is the second-most common diagnosis at outpatient neurology clinics represents an erroneous interpretation of the findings of the referenced 2010 paper.

FND is the current name for what was formerly called conversion disorder, the diagnosis previously given to patients believed to have psychogenic motor and gait dysfunctions, sensory deficits, and non-epileptic seizures. According to the 2013 edition of the Diagnostic and Statistical Manual of Mental Disorders and as noted in Perez et al, FND is not a diagnosis of exclusion but requires the presence of specific “rule-in” clinical signs believed to be incompatible with known neurological disease. Some of these clinical signs have long been used by neurologists and other clinicians to help them identify cases of conversion disorder.

Stone et al.,’s (2010) paper was one of several arising from the Scottish Neurological Symptoms Study (SNSS). The study reviewed records from multiple outpatient neurology clinics and reported that 209 of 3781 attendees, or less than 6 %, received diagnoses compatible with conversion disorder–in other words, what would now be called FND. In terms of ranking, this group of patients—labeled in the SNSS as having “functional” symptoms or diagnoses–was far down the list. The study found higher rates of many other conditions, including headache (19 %), epilepsy (14 %), peripheral nerve disorders (11 %), miscellaneous neurological disorders (10 %), multiple sclerosis/demyelination (7 %), spinal disorders (6 %) and Parkinson’s disease/movement disorders (6 %).

Earlier this year, a paper in the European Journal of Neurology (Mason et al., 2023) cited a different SNSS paper (Stone et al., 2009) to support the assertion that FND prevalence at outpatient neurology clinics was 5.4 %—far lower than the percentage needed to be the “2nd most common” diagnosis. Moreover, the authors of another paper (Foley et al., 2022) have recently issued a correction for the same misstatement of FND prevalence from the SNSS findings as the one identified in Perez et al.

The assertion that the SNSS found FND to be the “2nd most common” diagnosis at outpatient neurology clinics is based on a parallel and commonly repeated claim that the study found the prevalence in these settings to be 16 % (e.g. Ludwig et al., 2018). That rate is almost three times the 5.4 % prevalence recently highlighted in Mason et al. The extra patients included in this greatly expanded FND category were another 10 % collectively identified in the SNSS as having “psychological” symptoms or diagnoses. These “psychological” patients fell into a range of clinical sub-categories, among them hyperventilation, anxiety and depression, atypical facial/temporomandibular joint pain, post-head injury symptoms, fibromyalgia, repetitive strain injury, and alcohol excess. The SNSS paper cited in Perez et al reported that a combined grouping of the patients with “functional and psychological” symptoms or diagnoses had a prevalence of 16 % but did not provide any evidence that the 10 % included under the “psychological” label met, or could have met, the explicit FND requirement for rule-in clinical signs.

FND is not synonymous with the broader “functional and psychological” category in the SNSS and should not be presented as if it were. The post-hoc reinterpretation of previously reported data in a way that conflates FND with other complex conditions—almost tripling its apparent prevalence in the process–is an example of the phenomenon known as diagnostic creep. In any event, the SNSS results are a matter of record. Whatever future studies might determine about FND rates, the published findings cited by Perez et al and addressed in this letter do not support either the claim that it is the “2nd most common” diagnosis in outpatient neurology clinics or the related claim that its prevalence at these venues is 16 %.

Sincerely–

David Tuller (corresponding author)

Center for Global Public Health

School of Public Health

University of California, Berkeley

Berkeley, CA, USA

David Davies-Payne

Department of Radiology

Starship Children’s Hospital

Auckland, New Zealand

Jonathan Edwards

Department of Medicine

University College London

London, England, UK

Keith Geraghty

Centre for Primary Care and Health Services Research

Faculty of Biology, Medicine and Health

University of Manchester

Manchester, England, UK

Calliope Hollingue

Center for Autism and Related Disorders/Kennedy Krieger Institute

Department of Mental Health/Johns Hopkins Bloomberg School of Public Health

Johns Hopkins University

Baltimore, MD, USA

Mady Hornig

Department of Epidemiology

Columbia University Mailman School of Public Health

New York, NY, USA

Brian Hughes

School of Psychology

University of Galway

Galway, Ireland

Asad Khan

North West Lung Centre

Manchester University Hospitals

Manchester, England, UK

David Putrino

Department of Rehabilitation Medicine

Icahn School of Medicine at Mt Sinai

New York, NY, USA

John Swartzberg

Division of Infectious Diseases and Vaccinology

School of Public Health

University of California, Berkeley

Berkeley, CA, USA

Source: Correspondence: Inaccurate reference leads to tripling of reported FND prevalence. Neuroimage Clin. 2024 Feb 7;41:103537. doi: 10.1016/j.nicl.2023.103537. Epub ahead of print. PMID: 38330816. https://www.sciencedirect.com/science/article/pii/S2213158223002280 (Full text)

Implications of the quality of the doctor-patient relationship on health in adult ME/CFS patients. A qualitative public health study from a patient perspective

Abstract:

Background: Most patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are dissatisfied with medical care. They complain about e. g. the lack of medical recognition of ME/CFS as a neuroimmunological disease and the medical perception of those affected as “difficult patients”.

Method: As part of an exploratory qualitative survey, 544 medically diagnosed ME/CFS patients (> 20 years; 455 ♀, 89 ♂) were asked about their subjective experiences with regard to the doctor-patient relationships (DP relationship) to their treating physicians. The questionnaire was structured analogously to a focused, standardized guideline interview. The written answers were evaluated using a qualitative content analysis according to Mayring.

Results: The participants reported a significant deterioration in their health situation and their quality of life as a result of misdiagnoses and incorrect treatments, the strained DP relationship and the lack of support from the physicians. All of this leads to fear of visiting the doctor, a general loss of trust in physicians, a feeling of helplessness up to bitterness and resignation – with suicide as the last mental option for some patients to escape from this precarious situation. During medical consultations, other participants only addressed health problems that were not related to ME/CFS, or only went to the doctor in an emergency, or refrained from contacting doctors entirely.

Conclusions: The DP relationship described by the participants as problematic in their opinion has significant negative health consequences for them. It is therefore of great urgency to develop a patient-centred treatment concept that focuses on ME/CFS patients as experts on their own illness.

Source: Habermann-Horstmeier L, Horstmeier LM. Auswirkungen der Qualität der Arzt-Patient-Beziehung auf die Gesundheit von erwachsenen ME/CFS-Erkrankten : Eine qualitative Public-Health-Studie aus Patientensicht [Implications of the quality of the doctor-patient relationship on health in adult ME/CFS patients. A qualitative public health study from a patien perspective]. MMW Fortschr Med. 2023 Dec;165(Suppl 5):16-27. German. doi: 10.1007/s15006-023-2894-z. PMID: 38062324.

Health system support among patients with ME/CFS in Switzerland

Abstract:

Objectives: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex chronic and debilitating multifactorial disease. Adequate patient care is challenged by poor knowledge among health care professionals and the historical misconception that the disease is psychological in nature. This study assessed the health-related challenges faced by patients with ME/CFS in Switzerland and examined whether they receive adequate health care.

Methods: Quantitative and qualitative data were collected through a self-administered questionnaire between June and September of 2021, among 169 patients with ME/CFS in Switzerland.

Results: The mean age at diagnosis was 38.8 years. Only one-third of ME/CFS affected children and youth were correctly diagnosed before their 18th birthday. The mean time from disease onset to diagnosis was 6.7 years, and patients had an average of 11.1 different appointments and 2.6 misdiagnoses. A poor diagnosis rate and insufficient disease knowledge among health professionals in Switzerland led 13.5% of the patients to travel abroad to seek a diagnosis. Most patients (90.5%) were told at least once that their symptoms were psychosomatic. Swiss patients expressed high dissatisfaction with the health system and indicated that physicians lacked knowledge regarding ME/CFS. Therapies prescribed by physicians or tried by patients, as well as their perceived efficacy, were described. Graded Exercise Therapy (GET) was perceived as harmful by patients, whereas pacing, complementary/alternative medicine, and dietary supplements and medications to alleviate symptoms were reported to be helpful to varying degrees.

Conclusion: This study highlights that poor disease knowledge among health care providers in Switzerland has led to high patient dissatisfaction, and delays in ME/CFS diagnoses and prescription of inappropriate therapies, thus adding to patient distress and disease burden.

Source: Tschopp R, König RS, Rejmer P, Paris DH. Health system support among patients with ME/CFS in Switzerland. J Taibah Univ Med Sci. 2023 Jan 4;18(4):876-885. doi: 10.1016/j.jtumed.2022.12.019. PMID: 36852237; PMCID: PMC9957780. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9957780/ (Full text)

Impact of Misdiagnosis in Case-Control Studies of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

Misdiagnosis of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) can occur when different case definitions are used by clinicians (relative misdiagnosis) or when failing the genuine diagnosis of another disease (misdiagnosis in a strict sense). This problem translates to a recurrent difficulty in reproducing research findings.

To tackle this problem, we simulated data from case-control studies under misdiagnosis in a strict sense. We then estimated the power to detect a genuine association between a potential causal factor and ME/CFS. A minimum power of 80% was obtained for studies with more than 500 individuals per study group.

When the simulation study was extended to the situation where the potential causal factor could not be determined perfectly (e.g., seropositive/seronegative in serological association studies), the minimum power of 80% could only be achieved in studies with more than 1000 individuals per group.

In conclusion, current ME/CFS studies have suboptimal power under the assumption of misdiagnosis. This power can be improved by increasing the overall sample size using multi-centric studies, reporting the excluded illnesses and their exclusion criteria, or focusing on a homogeneous cohort of ME/CFS patients with a specific pathological mechanism where the chance of misdiagnosis is reduced.

Source: Malato J, Graça L, Sepúlveda N. Impact of Misdiagnosis in Case-Control Studies of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Diagnostics. 2023; 13(3):531. https://doi.org/10.3390/diagnostics13030531 https://www.mdpi.com/2075-4418/13/3/531 (Full text)

Mistaken Identity: Many Diagnoses are Frequently Misattributed to Lyme Disease

Abstract:

Background: Prior studies have demonstrated that Lyme disease is frequently over-diagnosed. However, few studies describe which conditions are misdiagnosed as Lyme disease.

Methods: This retrospective observational cohort study evaluated patients referred for Lyme disease to a Mid-Atlantic academic center between 2000-2013 who lacked evidence for Borrelia burgdorferi infection. The primary outcome is clinically described diagnoses contributing to symptoms. Secondary outcomes included symptom duration and determination whether diagnoses were new or attributed to existing medical conditions.

Results: Of 1261 referred patients, 1061 (84%) had no findings of active Lyme disease, with 690 (65%) receiving other diagnoses resulting in 405 (59%) having newly diagnosed medical conditions, 134 (19%) attributed to pre-existing medical issues, and 151 (22%) had both new and pre-existing conditions. Among the 690 patients, the median symptom duration was 796 days, and a total of 139 discrete diagnoses were made. Infectious disease diagnoses comprised only 3.2%. Leading diagnoses were anxiety/depression 222 (21%), fibromyalgia 120 (11%), chronic fatigue syndrome 77 (7%), migraine disorder 74 (7%), osteoarthritis 62 (6%) and sleep disorder/apnea 48 (5%). Examples of less frequent but non-syndromic diseases newly diagnosed included multiple sclerosis (11), malignancy (8), Parkinson’s disease (8), sarcoidosis (4) or amyotrophic lateral sclerosis (4).

Conclusions: Most patients with long-term symptoms have either new or pre-existing disorders accounting for their symptoms other than Lyme disease, suggesting overdiagnosis in this population. Patients referred for consideration of Lyme disease for chronic symptoms deserve careful assessment for diagnoses other than Borrelia burgdorferi infection.

Source: Kobayashi T, Higgins Y, Melia MT, Auwaerter PG. Mistaken Identity: Many Diagnoses are Frequently Misattributed to Lyme Disease. Am J Med. 2021 Nov 30:S0002-9343(21)00792-0. doi: 10.1016/j.amjmed.2021.10.040. Epub ahead of print. PMID: 34861197. https://www.sciencedirect.com/science/article/pii/S0002934321007920  (Full text)

Differentiating Psychosomatic, Somatopsychic, Multisystem Illnesses, and Medical Uncertainty

Abstract:

There is often difficulty differentiating between psychosomatic, somatopsychic, multisystem illness, and different degrees of medical uncertainty. Uncommon, complex, and multisystem diseases are commonly misdiagnosed. Two case histories are described, and relevant terms differentiating psychosomatic, somatopsychic, and multisystem illnesses are identified, reviewed, and discussed.

Adequate differentiation requires an understanding of the mind/body connection, which includes knowledge of general medicine, psychiatry, and the systems linking the body and the brain. A psychiatric diagnosis cannot be given solely based upon the absence of physical, laboratory, or pathological findings. Medically unexplained symptoms, somatoform disorder, and compensation neurosis are outdated and/or inaccurate terms. The terms subjective, nonspecific, and vague can be used inaccurately. Conversion disorders, functional disorders, psychogenic illness, factitious disorder imposed upon another (Munchausen’s syndrome by proxy), somatic symptom disorder, psychogenic seizures, psychogenic pain, psychogenic fatigue, and delusional parasitosis can be over-diagnosed. Bodily distress disorder and bodily distress syndrome are scientifically unsupported and inaccurate.

Many “all in your head” conditions may be related to the microbiome and the immune system. Better education concerning the interface between medicine and psychiatry and the associated diagnostic nomenclature as well as utilizing clinical judgment and thorough assessment, exercising humility, and maintaining our roots in traditional medicine will help to improve diagnostic accuracy and patient trust.

Source: Bransfield RC, Friedman KJ. Differentiating Psychosomatic, Somatopsychic, Multisystem Illnesses, and Medical Uncertainty. Healthcare (Basel). 2019 Oct 8;7(4). pii: E114. doi: 10.3390/healthcare7040114. https://www.mdpi.com/2227-9032/7/4/114/htm (Full article)

The Importance of Accurate Diagnosis of ME/CFS in Children and Adolescents: A Commentary

Abstract:

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a chronic illness that causes a range of debilitating symptoms. While most research has focused on adults, the illness also presents in children and adolescents. Many physicians find it difficult to diagnose the illness. In this commentary paper, we discuss a range of salient themes that have emerged from our ongoing research into the prevalence of ME/CFS in children and adolescents.

We discuss reasons why pediatric prevalence estimates vary widely in the literature, from almost 0% to as high as 3%. We argue that there is considerable misdiagnosis of pediatric cases and over-inflation of estimates of pediatric ME/CFS. Many children and teenagers with general fatigue and other medical complaints may meet loose diagnostic criteria for ME/CFS. We make recommendations for improving epidemiological research and identifying pediatric ME/CFS in clinical practice.

Source: Keith James Geraghty and Charles Adeniji. The Importance of Accurate Diagnosis of ME/CFS in Children and Adolescents: A Commentary. Front. Pediatr., 21 January 2019 | https://doi.org/10.3389/fped.2018.00435 (Full article)

Rethinking childhood adversity in chronic fatigue syndrome

Abstract:

Background: Previous studies have consistently shown increased rates of childhood adversity in chronic fatigue syndrome (CFS). However, such aetiopathogenic studies of CFS are potentially confounded by co-morbidity and misdiagnosis particularly with depression.

Purpose: We examined the relationship between rates of childhood adversity using two complimentary approaches (1) a sample of CFS patients who had no lifetime history of depression and (2) a modelling approach.

Methods: Childhood trauma questionnaire (CTQ) administered to a sample of 52 participants with chronic fatigue syndrome and 19 controls who did not meet criteria for a psychiatric disorder (confirmed using the Structured Clinical Interview for DSM-IV). Subsequently, Mediation Analysis (Baye’s Rules) was used to establish the risk childhood adversity poses for CFS with and without depression.

Results: In a cohort of CFS patients with depression comprehensively excluded, CTQ scores were markedly lower than in all previous studies and, in contrast to these previous studies, not increased compared with healthy controls. Post-hoc analysis showed that CTQ scores correlated with the number of depressive symptoms during the lifetime worst period of low mood. The probability of developing CFS given a history of childhood trauma is 4%, a two-fold increased risk compared to the general population. However, much of this risk is mediated by the concomitant development of major depression.

Conclusions: The data suggests that previous studies showing a relationship between childhood adversity and CFS may be attributable to the confounding effects of co-morbid or misdiagnosed depressive disorder.

Abbreviations: CFS: Chronic fatigue syndrome; CTQ: Childhood trauma questionnaire; MDD: Major depressive disorder; CA: Childhood adversity; P: Probability.

Source: Clark JE, Davidson SL, Maclachlan L, Newton JL, Watson S. Rethinking childhood adversity in chronic fatigue syndrome. Fatigue. 2017 Oct 10;6(1):20-29. doi: 10.1080/21641846.2018.1384095. eCollection 2018. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5774185/ (Full article)

Approaching recovery from myalgic encephalomyelitis and chronic fatigue syndrome: Challenges to consider in research and practice

Abstract:

There are unique methodological challenges to studying and assessing recovery in myalgic encephalomyelitis and chronic fatigue syndrome. This study explored these challenges through interviewing 13 physicians who treat myalgic encephalomyelitis and chronic fatigue syndrome. Our deductive thematic analysis produced four themes to consider when approaching recovery: lifespan differences in the illness experience; the heterogeneity of myalgic encephalomyelitis and chronic fatigue syndrome-case definitions, etiological stance, and misdiagnosis; patient follow-up and selection bias; and assessment logistics. We discuss how researchers and clinicians can use these considerations when working with patients, drafting recovery criteria, and interpreting treatment outcomes.

Source: Devendorf AR, Jackson CT, Sunnquist M, Jason LA. Approaching recovery from myalgic encephalomyelitis and chronic fatigue syndrome: Challenges to consider in research and practice. J Health Psychol. 2017 Nov 1:1359105317742195. doi: 10.1177/1359105317742195. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/29182007

Diagnosing Chronic Fatigue? Check For Sinusitis

Washington, D.C. – A new study published in the August 11 issue of the Archives of Internal Medicine demonstrates a possible link between unexplained chronic fatigue and sinusitis, two conditions previously not associated with each other. Also newly noted was a relationship between sinusitis and unexplained body pain. These findings offer new hope to patients lacking a diagnosis and treatment for fatigue and pain.

Sinus disease is seldom considered as a cause of unexplained chronic fatigue or pain, despite recent ear, nose, and throat (otolaryngology) studies documenting significant fatigue and pain in patients with sinusitis and dramatic improvement after sinus surgery. A Harvard study showed that fatigue and pain scores of sinusitis patients were similar or worse than a group 20 years older with congestive heart failure, lung disease, or back pain.

“Chronic fatigue is a condition that frustrates both doctors and their patients since treatments directed at just the symptoms without knowing the cause are typically ineffective,” said Alexander C. Chester, M.D., clinical professor of medicine at Georgetown University Medical Center and principal investigator of the pilot study. “While sinusitis will not be the answer for everyone who comes to an internist with unexplained fatigue or pain, this study does suggest that it should be considered as part of a patient’s medical evaluation.”

Through his private internal medicine practice, Chester questioned 297 patients, noting unexplained chronic fatigue in 22%, unexplained chronic pain in 11%, and both in 9%. While these numbers are consistent with previous studies, Chester observed an unusual connection between patients with chronic pain or fatigue: prevalent sinus symptoms. Sinus symptoms were nine times more common on average in patients with unexplained chronic fatigue than the control group, and six times more common in patients with unexplained chronic pain. In addition, sinus symptoms were more common in patients with unexplained fatigue than in patients with fatigue explained by a mental or physical illness, suggesting the syndrome of unexplained fatigue is more closely associated with sinusitis than are other types of fatigue.

The CDC approximates that sinusitis affects 32 million Americans. Rates are highest among women and people living in the South. Women comprised 46% of the participants in this study, but represented 60% of the group with fatigue, predominance also noted in most prior studies.

15 out of the 65 patients in Chester’s study met criteria for chronic fatigue syndrome (CFS), a severe form of unexplained chronic fatigue associated with body pains and other symptoms. Most CFS patients had sinus symptoms and many noted a sudden onset of their illness, similar to people with sinusitis.

“We clearly need to do more research to see if sinus treatments alleviate fatigue and pain. This study does, however, offer hope for possible help in the future.” said Chester.

Georgetown University Medical Center is an internationally recognized academic medical center with a three-part mission of research, teaching and patient care (through our partnership with MedStar Health). Our mission is carried out with a strong emphasis on public service and a dedication to the Catholic, Jesuit principle of cura personalis–or “care of the whole person.” The Medical Center includes the School of Medicine and the School of Nursing and Health Studies, both nationally ranked, and the world renowned Lombardi Cancer Center.

 

Source: Georgetown University Medical Center. (2003, August 14). Diagnosing Chronic Fatigue? Check For Sinusitis. ScienceDaily. Retrieved March 4, 2017 from  https://www.sciencedaily.com/releases/2003/08/030814072847.htm