Investigating the effectiveness and cost-effectiveness of FITNET-NHS (Fatigue In Teenagers on the interNET in the NHS) compared to Activity Management to treat paediatric chronic fatigue syndrome (CFS)/myalgic encephalomyelitis (ME): protocol for a randomised controlled trial

Investigating the factors associated with meaningful improvement on the SF-36-PFS and exploring the appropriateness of this measure for young people with ME/CFS accessing an NHS specialist service: a prospective cohort study

OBJECTIVES

Paediatric myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is relatively common and disabling, but little is known about the factors associated with outcome. We aimed to describe the number and characteristics of young people reaching the 10-point minimal clinically important difference (MCID) of SF-36-Physical Function Subscale (SF-36-PFS) and to investigate factors associated with reaching the MCID.

DESIGN

Prospective observational cohort study.

SETTING

A specialist UK National Health Service ME/CFS service, Southwest England; recruitment between March 2014 and August 2015.

PARTICIPANTS

193 eligible patients with ME/CFS aged 8-17 years reported baseline data. 124 (65%) and 121 (63%) with outcome data at 6 and 12 months, respectively.

OUTCOME MEASURES

SF-36-PFS (primary outcome). Chalder Fatigue Questionnaire, school attendance, visual analogue pain scale, Hospital Anxiety and Depression Scale, Spence Young People Anxiety Scale, Clinical Global Impression scale and EQ-5D-Y (secondary).

RESULTS

At 6 months 48/120 (40%) had reached the MCID for SF-36-PFS. This had increased to 63/117 (54%) at 12 months. On the Clinical Global Impressions, 77% and 79% reported feeling either a little better, much better or very much better. Those with worse SF-36-PFS at baseline assessment were more likely to achieve the MCID for SF-36-PFS at 6 months (odds ratio 0.97, 95% confidence interval 0.96 to 0.99, p value 0.003), but there was weaker evidence of effect at 12 months (OR 0.98, 95% CI 0.97 to 1.00, p value 0.038). No other factors at baseline were associated with the odds of reaching the MCID at 6 months. However, at 12 months, there was strong evidence of an effect of pain on MCID (OR 0.97, 95% CI 0.95 to 0.99, p value 0.001) and SF-36-PFS on MCID (OR 0.96, 95% CI 0.94 to 0.98, p value 0.001).

CONCLUSIONS

40% and 54% of young people reached the MCID at 6 and 12 months, respectively. No factors at assessment (other than SF-36-PFS at 6 months, and pain and SF-36-PFS at 12 months) are associated with MCID of SF-36-PFS at either 6 or 12 months. Further work is needed to explore the most appropriate outcome measure for capturing clinical meaningful improvement for young people with ME/CFS.

A Comprehensive Update of the Current Understanding of Chronic Fatigue Syndrome

This is a comprehensive literature review of chronic fatigue syndrome (CFS). We provide a description of the background, etiology, pathogenesis, diagnosis, and management regarding CFS. CFS is a multifaceted illness that has many symptoms and a wide array of clinical presentations. As of recent, CFS has been merged with myalgic encephalomyelitis (ME). Much of the difficulty in its management has stemmed from a lack of a concrete understanding of its etiology and pathogenesis. There is a potential association between dysfunction of the autoimmune, neuroendocrine, or autonomic nervous systems and the development of CFS. Possible triggering events, such as infections followed by an immune dysregulation resulting have also been proposed. In fact, ME/CFS was first described following Epstein Barr virus (EBV) infections, but it was later determined that it was not always preceded by EBV infection. Patient diagnosed with CFS have shown a noticeably earlier activation of anaerobic metabolism as a source of energy, which is suggestive of impaired oxygen consumption. The differential diagnoses range from tick-borne illnesses to psychiatric disorders to thyroid gland dysfunction. Given the many overlapping symptoms of CFS with other illnesses makes diagnosing it far from an easy task. The Centers for Disease Control and Prevention (CDC) considers it a diagnosing of exclusion, stating that self-reported fatigue for at minimum of six months and four of the following symptoms are necessary for a proper diagnosis: memory problems, sore throat, post-exertion malaise, tender cervical or axillary lymph nodes, myalgia, multi-joint pain, headaches, and troubled sleep. In turn, management of CFS is just as difficult. Treatment ranges from conservative, such as cognitive behavioral therapy (CBT) and antidepressants, to minimally invasive management. Minimally invasive management involving ranscutaneous electrical acupoint stimulation of target points has demonstrated significant improvement in fatigue and associated symptoms in a 2017 randomized controlled study. The understanding of CFS is evolving before us as we continue to learn more about it. As further reliable studies are conducted, providing a better grasp of what the syndrome encompasses, we will be able to improve our diagnosis and management of it.

Effectiveness of Internet-Based Cognitive Behavior Therapy (Fatigue in Teenagers on the Internet) for Adolescents With Chronic Fatigue Syndrome in Routine Clinical Care: Observational Study

Background

Internet-based cognitive behavior therapy (I-CBT) for adolescents with chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) has been shown to be effective in a randomized controlled trial (RCT; Fatigue in Teenagers on the Internet [FITNET]). FITNET can cause a significant reduction in fatigue and disability.

Objective

We aimed to investigate whether FITNET treatment implemented in routine clinical care (IMP-FITNET) was as effective, using the outcomes of the FITNET RCT as the benchmark.

Methods

Outcomes of CFS/ME adolescents who started IMP-FITNET between October 2012 and March 2018 as part of routine clinical care were compared to the outcomes in the FITNET RCT. The primary outcome was fatigue severity assessed posttreatment. The secondary outcomes were self-reported physical functioning, school attendance, and recovery rates. Clinically relevant deterioration was assessed posttreatment, and for this outcome, a face-to-face CBT trial was used as the benchmark. The attitude of therapists toward the usability of IMP-FITNET was assessed through semistructured interviews. The number of face-to-face consultations during IMP-FITNET was registered.

Results

Of the 384 referred adolescents with CFS/ME, 244 (63.5%) started IMP-FITNET, 84 (21.9%) started face-to-face CBT, and 56 (14.6%) were not eligible for CBT. Posttreatment scores for fatigue severity (mean 26.0, SD 13.8), physical functioning (mean 88.2, SD 15.0), and full school attendance (mean 84.3, SD 26.5) fell within the 95% CIs of the FITNET RCT. Deterioration of fatigue and physical functioning after IMP-FITNET was observed at rates of 1.2% (n=3) and 4.1% (n=10), respectively, which is comparable to a waiting list condition (fatigue: 1.2% vs 5.7%, χ²₁=3.5, P=.06; physical functioning: 4.1% vs 11.4%, χ²₁=3.3, P=.07). Moreover, 41 (16.8%) IMP-FITNET patients made use of face-to-face consultations.

Conclusions

IMP-FITNET is an effective and safe treatment for adolescents with CFS/ME in routine clinical care.

Cost-effectiveness of Interventions for Chronic Fatigue Syndrome or Myalgic Encephalomyelitis: A Systematic Review of Economic Evaluations

INTRODUCTION

Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) has profound quality of life and economic consequences for individuals, their family, formal services and wider society. Little is known about which therapeutic interventions are more cost-effective.

OBJECTIVE

A systematic review was carried out to identify and critically appraise the evidence on the cost-effectiveness of CFS/ME interventions.

METHODS

The review protocol was prespecified (PROSPERO: CRD42018118731). Searches were carried out across two databases-MEDLINE (1946-2020) and EMBASE (1974-2020). Additional studies were identified by searching reference lists. Only peer-reviewed journal articles of full economic evaluations examining CFS/ME interventions were included. Trial- and/or model-based economic evaluations were eligible. Data extraction and screening were carried out independently by two reviewers. The methodological quality of the economic evaluation and trial were assessed using the Consensus Health Economic Criteria checklist (CHEC-list) and Risk of Bias-2 (RoB-2) tool, respectively. A narrative synthesis was used to summarise the economic evidence for interventions for adults and children in primary and secondary care settings.

RESULTS

Ten economic evaluations, all based on data derived from randomised controlled trials, met our eligibility criteria. Cognitive behavioural therapy (CBT) was evaluated across five studies, making it the most commonly evaluated intervention. There was evidence from three trials to support CBT as a cost-effective treatment option for adults; however, findings on CBT were not uniform, suggesting that cost-effectiveness may be context-specific. A wide array of other interventions were evaluated in adults, including limited evidence from two trials supporting the cost effectiveness of graded exercise therapy (GET). Just one study assessed intervention options for children. Our review highlighted the importance of informal care costs and productivity losses in the evaluation of CFS/ME interventions.

CONCLUSIONS

We identified a limited patchwork of evidence on the cost-effectiveness of interventions for CFS/ME. Evidence supports CBT as a cost-effective treatment option for adults; however, cost-effectiveness may depend on the duration and frequency of sessions. Limited evidence supports the cost effectiveness of GET. Key weaknesses in the literature included small sample sizes and short duration of follow-up. Further research is needed on pharmacological interventions and therapies for children.

"The child's got a complete circle around him". The care of younger children (5-11 years) with CFS/ME. A qualitative study comparing families', teachers' and clinicians' perspectives'

Society needs to improve the care of children with complex needs. Guidelines recommend integrating care across health and educational settings, however, there is little research on whether this is achieved or how this can be done in practice. Our aim was to address this gap by examining how the care of children (aged 5-11 years) with Chronic Fatigue Syndrome/ Myalgic Encephalomyelitis (CFS/ME) is shared across home, education and health settings, in order to generate recommendations for integrating care. We undertook semi-structured interviews with families (22 participants), teachers (11 participants) and healthcare providers (9 participants), analysing the data thematically and comparatively. Our analysis of the data was informed by a socio-ecological perspective as we sought to understand the complexity of the relationships and systems around the child. The first theme focuses on the child ("individual level"); child-centred care is seen as essential whilst acknowledging that the child has limited capacity to manage their own care. The second theme presents the distinct roles of parents, teachers and clinicians ("interpersonal and organisational levels"). The third describes how these three levels interact in the management of the child's care, in the context of the health and education systems and policies ("policy levels"). The fourth explores optimal ways to integrate care across home, school and clinical settings. In conclusion, there is opportunity to support a child with complex health needs by targeting the systems around the child; parents, teachers and clinicians, as well as education and health policy that can enable shared-care. Involving schools in assessment, communicating diagnosis across settings and using a stepped-care approach to integrated care may be beneficial. Further work is needed to explore these recommendations, with attention to the policy factors that may act as barriers and enablers.

Sleep problems in adolescents with CFS: A case-control study nested within a prospective clinical cohort

Sleep problems have a negative impact on a range of outcomes and are very common in adolescents with chronic fatigue syndrome (CFS). We aimed to (a) establish whether adolescents with CFS have more self-reported sleep problems than illness controls as well as healthy controls, (b) investigate changes in sleep problems and (c) explore the extent to which sleep problems at baseline predict fatigue and functioning at follow-up in adolescents with CFS. The Insomnia Scale was completed by 121 adolescents with CFS, 78 healthy adolescents and 27 adolescents with asthma. Eighty (66%) treatment-naïve adolescents with CFS completed questionnaires approximately 3 months later. Adolescents with CFS reported increased sleep problems compared to healthy controls and adolescents with asthma. In CFS, there was no significant change in sleep problems without treatment over a 3-month follow-up. Sleep problems at baseline predicted a significant proportion of the variance in sleep problems at follow-up. Sleep problems should be targeted in treatment. Regulating the 'body clock' via the regulation of sleep could influence outcomes not assessed in this study such as school attainment.

Do adolescents with chronic fatigue syndrome (CFS/ME) and co-morbid anxiety and/or depressive symptoms think differently to those who do not have co-morbid psychopathology?

BACKGROUND

Co-morbid anxiety and/or depression is common in adolescents with Chronic Fatigue Syndrome (CFS/ME). Adolescents with psychopathology typically endorse more negative cognitive errors. We do not know whether they make negative cognitive errors in response to fatigue. We examined the thinking patterns of adolescents with CFS/ME and co-morbid psychopathology compared to those without this co-morbidity.

METHODS

This cross-sectional study recruited 205 adolescents (age 11-18) with CFS/ME, who completed measures of anxiety and depression, information processing biases and responses to fatigue. We grouped participants as having co-morbid psychopathology (or not) by applying a threshold score. We compared groups' thinking pattern subscale scores using independent samples T tests. We examined the association between psychopathology and general negative thinking and specific responses to fatigue symptoms.

RESULTS

Adolescents with CFS/ME with co-morbid psychopathology more strongly endorsed general negative cognitive errors (d = 0.61-1.31). They also more strongly endorsed damage beliefs (d = 0.49), embarrassment avoidance (d = 1.05), catastrophising (d = 0.97) and symptom focusing (d = 0.75) in response to fatigue but did not differ significantly on fear avoidance from those without co-morbid psychopathology. Both negative cognitive errors and unhelpful responses to symptoms explained 43% of the variance in psychopathology.

CONCLUSIONS

Adolescents with CFS/ME with co-morbid psychopathology tend to be negatively biased in their thinking, both generally and about their symptoms of fatigue specifically. This may have implications for the sequencing of cognitive and behavioural strategies to address both fatigue and psychopathology.

Recruiting Adolescents With Chronic Fatigue Syndrome/Myalgic Encephalomyelitis to Internet-Delivered Therapy: Internal Pilot Within a Randomized Controlled Trial

BACKGROUND

Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) in adolescents is common and disabling. Teenagers in the United Kingdom are more likely to recover if they access specialist care, but most do not have access to a local specialist CFS/ME service. Delivering treatment remotely via the internet could improve access to treatment.

OBJECTIVE

This study aims to assess (1) the feasibility of recruitment and retention into a trial of internet-delivered specialist treatment for adolescents with CFS/ME and (2) the acceptability of trial processes and 2 web-based treatments (to inform continuation to full trial).

METHODS

This study is an internal pilot for the initial 12 months of a full randomized controlled trial (RCT), with integrated qualitative methods (analysis of recruitment consultations and participant and clinician interviews). Recruitment and treatment were delivered remotely from a specialist pediatric CFS/ME treatment service within a hospital in South West United Kingdom. Adolescents (aged 11-17 years) from across the United Kingdom with a diagnosis of CFS/ME and no access to local specialist treatment were referred by their general practitioner to the treatment center. Eligibility assessment and recruitment were conducted via remote methods (telephone and on the web), and participants were randomized (via a computer-automated system) to 1 of 2 web-based treatments. The trial intervention was Fatigue in Teenagers on the InterNET in the National Health Service, a web-based modular CFS/ME-specific cognitive behavioral therapy program (designed to be used by young people and their parents or caregivers) supported by individualized clinical psychologist electronic consultations (regular, scheduled therapeutic message exchanges between participants and therapist within the platform). The comparator was Skype-delivered activity management with a CFS/ME clinician (mainly a physiotherapist or occupational therapist). Both treatments were intended to last for up to 6 months. The primary outcomes were (1) the number of participants recruited (per out-of-area referrals received between November 1, 2016, to October 31, 2017) and the proportion providing 6-month outcome data (web-based self-report questionnaire assessing functioning) and (2) the qualitative outcomes indicating the acceptability of trial processes and treatments.

RESULTS

A total of 89 out of 150 (59.3% of potentially eligible referrals) young people and their parents or caregivers were recruited, with 75 out of 89 (84.2%) providing 6-month outcome data. Overall, web-based treatment was acceptable; however, participants and clinicians described both the advantages and disadvantages of remote methods. No serious adverse events were reported.

CONCLUSIONS

Recruiting young people (and their parents or caregivers) into an RCT of web-based treatment via remote methods is feasible and acceptable. Delivering specialist treatment at home via the internet is feasible and acceptable, although some families prefer to travel across the United Kingdom for face-to-face treatment.

TRIAL REGISTRATION

ISRCTN 18020851; http://www.isrctn.com/ISRCTN18020851.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.1186/s13063-018-2500-3.

Can linguistic analysis be used to identify whether adolescents with a chronic illness are depressed?

Comorbid depression is common in adolescents with chronic illness. We aimed to design and test a linguistic coding scheme for identifying depression in adolescents with chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME), by exploring features of e-consultations within online cognitive behavioural therapy treatment. E-consultations of 16 adolescents (aged 11-17) receiving FITNET-NHS (Fatigue in teenagers on the interNET in the National Health Service) treatment in a national randomized controlled trial were examined. A theoretically driven linguistic coding scheme was developed and used to categorize comorbid depression in e-consultations using computerized content analysis. Linguistic coding scheme categorization was subsequently compared with classification of depression using the Revised Children's Anxiety and Depression Scale published cut-offs (t-scores ≥65, ≥70). Extra linguistic elements identified deductively and inductively were compared with self-reported depressive symptoms after unblinding. The linguistic coding scheme categorized three (19%) of our sample consistently with self-report assessment. Of all 12 identified linguistic features, differences in language use by categorization of self-report assessment were found for "past focus" words (mean rank frequencies: 1.50 for no depression, 5.50 for possible depression, and 10.70 for probable depression; p < .05) and "discrepancy" words (mean rank frequencies: 16.00 for no depression, 11.20 for possible depression, and 6.40 for probable depression; p < .05). The linguistic coding profile developed as a potential tool to support clinicians in identifying comorbid depression in e-consultations showed poor value in this sample of adolescents with CFS/ME. Some promising linguistic features were identified, warranting further research with larger samples.

Investigating the effectiveness and cost-effectiveness of FITNET-NHS (Fatigue In Teenagers on the interNET in the NHS) compared to activity management to treat paediatric chronic fatigue syndrome (CFS)/myalgic encephalomyelitis (ME): amendment to the published protocol

Abstract

The FITNET-NHS Trial is a UK, national, trial investigating whether an online cognitive behavioural therapy program (FITNET-NHS) for treating chronic fatigue syndrome/ME in adolescents is clinically effective and cost-effective in the NHS. At the time of writing (September 2019), the trial was recruiting participants. This article presents an update to the planned sample size and data collection duration previously published within the trial protocol.

Trial registration

ISRCTN, ID: 18020851. Registered 8 April 2016.

Child and adolescent chronic fatigue syndrome/myalgic encephalomyelitis: where are we now?

PURPOSE OF REVIEW

The current review aims to determine the recent evidence regarding cause, impact, effective treatment and prognosis of children and young people (CYP) affected by chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) at a time when the National Institute for Clinical Excellence guidelines in the United Kingdom are being reviewed and more research is called for worldwide.

RECENT FINDINGS

CFS/ME is a debilitating illness with no clear cause. This review describes the heterogeneous clinical picture and the effects on the young person and family. Comorbidities such as mood disorders and pain are discussed including evidence for treatment. The various aetiological hypotheses are discussed and the precipitating factors identified. The evidence base is limited regarding effective treatment for CYP with CFS/ME, particularly the severely affected group. A large trial of online cognitive behavioural therapy with teenagers is being explored in the United Kingdom. The Lightning Process has been shown to be effective when added to medical care.

SUMMARY

Current evidence is hampered by different diagnostic criteria, the heterogeneous nature of the condition, and limited number of small studies. There is a clear need for more research and larger studies exploring the cause of and most effective treatment for CYP with CFS/ME.

"It's not one size fits all"; the use of videoconferencing for delivering therapy in a Specialist Paediatric Chronic Fatigue Service

BACKGROUND

There are few specialist paediatric Chronic Fatigue Syndrome (CFS/ME) services in the UK. Therefore, the distance some families have to travel to reach these services can be a barrier to accessing evidence-based treatment. Videoconferencing technology such as Skype provides a means of delivering sessions remotely. This study aimed to explore the views of children and young people, their parents, and healthcare professionals of treatment delivered by videoconferencing in a specialist paediatric CFS/ME team.

METHOD

To explore the experiences of the participants, a qualitative design was selected. Twelve young people (age 9-18), and 6 parents were interviewed about their experience of treatment sessions delivered via videoconferencing within a specialist CFS/ME service. A focus group explored the views of healthcare professionals (N = 9) from the service. Thematic analysis was used.

RESULTS

Three themes were identified from the data: "Challenges and concerns", "Benefits" and "Treatment provision". Challenges and concerns that participants identified were; difficulties experienced with technology; a sense of a part of communication being lost with virtual connections; privacy issues with communicating online and feeling anxious on a screen. Participants felt that benefits of videoconferencing were; improving access to the chronic fatigue service; convenience and flexibility of treatment provision; a sense of being more open online and being in the comfort of their own home. In terms of treatment provision participants talked about videoconferencing as a part of a hierarchy of communication; the function of videoconferencing within the context of the chronic fatigue service; additional preparation needed to utilise videoconferencing and an assumption that videoconferencing is "part of young people's lives".

CONCLUSIONS

Although the experience of sessions provided by videoconferencing was different to sessions attended in person, participants tended to be positive about videoconferencing as an alternative means of accessing treatment, despite some barriers. Videoconferencing could be an additional option within an individualised care plan, but should not be an alternative to face to face support.

Chronic fatigue syndrome (CFS): Suggestions for a nutritional treatment in the therapeutic approach

Chronic fatigue syndrome (CFS) is known as a multi-systemic and complex illness, which induces fatigue and long-term disability in educational, occupational, social, or personal activities. The diagnosis of this disease is difficult, due to lacking a proper and suited diagnostic laboratory test, besides to its multifaceted symptoms. Numerous factors, including environmental and immunological issues, and a large spectrum of CFS symptoms, have recently been reported. In this review, we focus on the nutritional intervention in CFS, discussing the many immunological, environmental, and nutritional aspects currently investigated about this disease. Changes in immunoglobulin levels, cytokine profiles and B- and T- cell phenotype and declined cytotoxicity of natural killer cells, are commonly reported features of immune dysregulation in CFS. Also, some nutrient deficiencies (vitamin C, vitamin B complex, sodium, magnesium, zinc, folic acid, l-carnitine, l-tryptophan, essential fatty acids, and coenzyme Q₁₀) appear to be important in the severity and exacerbation of CFS symptoms. This review highlights a far-driven analysis of mineral and vitamin deficiencies among CFS patients.

Defining the minimally clinically important difference of the SF-36 physical function subscale for paediatric CFS/ME: triangulation using three different methods

BACKGROUND

Defining the minimally clinically important difference (MCID) is important for the design and analysis of clinical trials and ensures that findings are clinically meaningful. Studies in adult populations have investigated the MCID of The Short Form 36 physical function sub-scale (SF-36-PFS). However, to our knowledge no studies have defined the MCID of the SF-36-PFS in a paediatric population. We aimed to triangulate findings from distribution, anchor and qualitative methods to identify the MCID of the SF-36-PFS for children and adolescents with CFS/ME.

METHODS

Quantitative methods: We analysed routinely-collected data from a specialist paediatric CFS/ME service in South-West England using: 1) the anchor method, based on Clinical Global Impression (CGI) outcomes at 6 months' follow-up; 2) the distribution method, based on the standard deviation of baseline SF-36-PFS scores. Qualitative methods: Young people (aged 12-17 years) and parents were asked to complete the SF-36-PFS, marking each question twice: once for where they would currently rate themselves/their child and a second time to show what they felt would be the smallest amount of change for them/their child to feel treatment had made a difference. Semi-structured interviews were designed to explore what factors were deemed important to patients and to what extent an improvement was considered satisfactory. We thematically analysed qualitative interviews from 21 children and their parents.

RESULTS

Quantitative results: Six-month follow-up data were available for 198 children with a mean age of 14 years. Most were female (74%, 146/198) and 95% gave their ethnicity as "White British". Half the standard deviation of the baseline SF-36-PFS scores was 11.0. "A little better" on the CGI equated to a mean difference on the SF-36-PFS from baseline to 6-month follow-up of 9.0. Qualitative results: Twenty-one children with CFS/ME participated: 16 females (76.2%) with a mean age of 14.4 years. Twenty mothers and two fathers were also interviewed. The median minimal improvement in the SF-36-PFS was 10. Participants indicated that small changes in physical function can lead to important improvements in valued social and family function. Patients and parents were positive about improvement even in the presence of persisting symptoms. Triangulation: The MCID based on the mean score from the three methods was 10.

CONCLUSIONS

Converging evidence indicates future studies in paediatric CFS/ME should use an MCID of 10 on the SF-36-PFS.

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

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.