NICE Revisions backed by evidence

In this article:

The NICE Revisions Explained

The  National Institute for Health and Care Excellence (NICE) guidelines are the principle clinical guidance for the UK, and are utilised by many other countries, including Aotearoa/New Zealand. In October 2021, the NICE released revised guidelines for the diagnosis, treatment, and management of Myalgic Encephalomyelitis (ME) / Chronic Fatigue Syndrome (CFS).1

The publication of these guidelines represents a significant opportunity to correct historic misinformation about ME/CFS, and to ensure educators and clinicians have current, methodologically-sound evidence to guide their understanding of pathophysiology, assessment, and management.  

Revision of the ME/CFS NICE guidelines occurred over several years (2017-2021) and followed the standard robust NICE review processes. This included evaluation of the research evidence using the GRADE framework, a widely adopted system for formulating clinical practice recommendations.  Analysis of the evaluation was then conducted by a panel of clinicians and lay persons, followed by review by the NICE guideline committee. The Committee was chaired by Clinical advisor and paediatrician Dr. Peter Barry and Vice Chair Baroness Finlay, Consultant in Palliative Medicine, Clinical Lead for Palliative Care for Wales.

The major changes in the NICE guidelines for ME/CFS are: 

  • Acknowledgement of the cardinal diagnostic symptom of Post Exertional Malaise (PEM), a worsening of symptoms after activity. 
  • The removal of Cognitive Behavioural Therapy (CBT) and Graded Exercise Therapy (GET)  as recommended treatment 
  • The recommendation that Lightning Process should NOT be used to treat ME/CFS 
  • Treatment focus is on symptom management.
summary of recommendation available on NICE website

The historical use of Cognitive Behavioural therapy (CBT) and graded exercise therapy (GET) as a treatment for ME/CFS stemmed from an inaccurate formulation that psychological factors are key in the causation and/or maintenance of symptoms. The risk to people with ME/CFS was that cognitive behavioural techniques urged people to view their symptoms as exaggerated illness behaviours and to counter this by engaging in increasing levels of activity/exercise. Exceeding the energy envelope risks Post Exertional Malaise (PEM) and can result in a prolonged or permanent worsening of the condition.

As evidence of the pathophysiology underlying ME/CFS has mounted, and the potential for harm of CBT and GET has become clear, CBT/GET has been abandoned as a treatment strategy in the USA and many other countries. Major guidance publications have either dropped all reference to these and related therapies, or cautioned against the use of them (e.g. CDC, IoM/NAM).
The 2021 publication of the NICE guidelines likewise clarified that there is insufficient evidence for the use of CBT and GET and removed the recommendation.
The NICE review process also discredited the validity of research included in the 2007 NICE guidelines that claimed these strategies were safe and effective. Evaluations of the quality of evidence used in 2007 to develop these claims, determined that across 172 individual CBT outcomes, as examined across multiple studies, all evidence cited for CBT was found to be of “low” or “very low” methodological quality. Similarly across 64 individual GET outcomes, all evidence for GET was of “low” or “very low” quality. 

The NICE committee took the scrutiny of evidence for psychological therapies a step further by singling out the Lightning Process for additional evaluation. This is a programme, developed by a UK osteopath, that promotes a rudimentary neurolinguistic programming technique as curative of a range of conditions, primarily ME/CFS, and more recently long Covid. The concerns around this programme stem from the formulation that ME/CFS symptoms are a learned response to stress and that alternate responses need to be rewired.  This can result in people engaging in actions that precipitate Post Exertional Malaise thus worsening their condition. The NICE Committee found available evidence for the Lightning Process to be of “very low” quality upon review and now recommends that the Lightning Process not be offered to people with ME/CFS. Furthermore, the British Standard Advertising Authority took legal action against the Lightning Process owners, citing false advertising due to unsubstantiated claims. This action was upheld.

In spite of a lack of evidence for CBT/GET and other therapies such as Lightning Process, there are influential academic and clinical groups in the UK and some European countries, who continue to promote and research psychological interpretations of ME/CFS. In New Zealand, in the face of a proliferation of evidence showing a pathophysiological basis for symptoms, and growing numbers of people being diagnosed with ME/CFS following PASC (long covid), some clinicians in New Zealand remain unaware of this evidence and potential harm, and continue to promote psychological therapies as curative. This is in spite of The Ministry of Health’s recognition of  ME/CFS as biomedical in 2002, and removal of CBT/GET in the clinical advice in the regional Health Pathways in New Zealand from 2019.

In December 2022, the Ministry of Health supported the conclusions of the guidance for ME/CFS published by NICE (2021) saying ‘that ME/CFS is a serious and complex medical condition/disease with varying severity rather than a mental health condition and that there is not a primary psychological basis underlying its development and/or maintenance.’

The NICE Guidelines (2021) now include best practice recommendations for treatment focussing on symptom management and emphasise the importance of energy management techniques, such as pacing, that are proven to be effective in preventing or minimising Post Exertional Malaise (PEM) – the diagnostic characteristic of ME.

“The keys to pacing are knowing when to stop and rest by listening to and understanding one’s own body, taking a flexible approach and staying within one’s limits; different people use different techniques to do this.” – NICE Guidelines 

Final words

ME/CFS is a complex, debilitating condition and best practice care involves a person-centred approach where symptom management is the key to controlling the fluctuating relapse and remittance that occurs. Evidence-based strategies that are shown to be effective are pacing and energy management, and symptom management strategies including a care and support plan, good nutrition, specialist physiotherapy, rest, sleep and pain management.

ANZMES considers the 2021 NICE guidelines to be comprehensive, evidence-based, and backed by a rigorous review process.  We encourage all healthcare professionals, medical bodies, medical schools, and ministry staff (in particular MoH, MSD) in New Zealand to update their understanding of ME/CFS and to become acquainted with the 2021 NICE guidelines.  

It’s one of the biggest challenges in clinical practice in medicine or psychology to try to work with somebody for whom you have no answers, you have no magic bullets. So it is disappointing but one of the reasons we have maybe a shortage of evidence-based treatments for this condition is because of the emphasis on cognitive behavioural therapy and GET … the research is very behind on where it would be if there was actually a level playing field to begin with.
The unfair emphasis on these treatments has created this deficit of knowledge. You have to manage the symptoms of this condition … but to use that as some kind of rationale for retaining therapies that we know are ineffective, doesn’t follow logically.

Professor Brian Hughes, BA, EdM, PhD, Psychology Professor NUI Galway.2

If you are a medical professional or member of a medical body or ministry staff member who would like to know more about ME/CFS, including the up-to-date scientific research, and evidence-based treatment options, please contact ANZMES.

World ME Alliance responds to opinion piece

In July 2023 an article titled “Anomalies in the review process and interpretation of the evidence in the NICE guideline for chronic fatigue syndrome and myalgic encephalomyelitis” was published in the Journal of Neurology and Neurosurgery and Psychiatry (JNNP).

The World ME Alliance provided a rapid response to the article which the JNNP chose not to publish.

The World ME Alliance, of which ANZMES is a founding member, is a global collective of national organisations with 27 member organisations (24 at the time of the rapid response).

The full response can be read on the World ME Alliance website.

JNNP publishes detailed NICE response article

On March 1st, 2024, the Journal of Neurology and Neurosurgery and Psychiatry (JNNP) published a full article from authors of the NICE guideline on #MECFS, clearly laying out how this guideline is a rigorous and accurate assessment of current knowledge. Through this, the authors demonstrate the reliability and importance of the recommendations on care for people with ME.

Read the full article here:

2Professor Brian Hughes interview minute 19.09:

National Advisory on ME releases Best Practice Guidance with clinician and researcher support.

The Aotearoa/New Zealand National Advisory on ME (ANZMES) has released best practice guidance for the diagnosis and management of Myalgic Encephalomyelitis / Chronic Fatigue Syndrome. There is a call for national guidelines to be developed in consultation with ANZMES, to ensure only the latest evidence-based research and data is adopted and used by the health profession. New Zealand-based and international reputable ME/CFS and long COVID researchers and clinicians have signed their names in support of this newly released guidance. The document has been sent to the relevant health associations, medical bodies, and medical schools. The document can be seen below:

The words with best practice written with chalk and images of light bulbs one is yellow the rest are white

Executive Summary


As the National Advisory on Myalgic Encephalomyelitis (ME), we present the latest updates to best practice international guidelines for immediate use to standardise care in New Zealand.  This document highlights the critical importance of adhering to current, evidence-based recommendations, incorporating expert consensus for the diagnosis and management of ME while moving away from practices that have been proven to be harmful or disproven by contemporary research.


Advances in research have evolved our understanding of ME, refining diagnosis criteria and symptom management. Research now shows clearly that the basis of ME is biomedical rather than psychological, with multi-systemic dysfunction driving pathogenesis and symptom progression. Guidelines for clinical practice reflect this understanding.

Key practice points:

  • The  Institute of Medicine (2015) Criteria are the preferred diagnostic criteria for ME.
  • The Canadian Consensus Criteria are the preferred criteria in research for ME.
  • International guidelines from institutions like the Mayo Clinical Proceedings, Centers for Disease Control and Prevention (CDC), and National Institute of Health and Care Excellence (NICE) provide an up-to-date framework for healthcare professionals to navigate the complexities of symptom management in ME.
  • International guidelines uniformly advocate a multidisciplinary approach,  emphasising the identification and management of the cardinal symptom – Post-Exertional Malaise (PEM).
  • Symptom management is the focus of treatment with emphasis on pacing – a free energy management technique used to avoid PEM. Ignoring these guidelines can worsen a patient’s condition.
  • Robust review of evidence has led to the removal of three previously recommended treatments from international guidelines – Cognitive Behavioural Therapy (CBT), Graded Exercise Therapy (GET), Lightning Process. Continuing to perpetuate the prescription of these treatments may cause harm.

International best practice guidelines play a crucial role in standardising care and improving patient outcomes. We are committed to supporting best practice care for people with ME and we offer resources, training and access to up-to-date guidelines that can assist in aligning NZ medical practice with the latest robust, evidence-based recommendations.

Best Practice Guidelines 

Presented below are the most current evidence-based, reputable international guidelines for the diagnosis and management of ME (also known as Chronic Fatigue Syndrome (CFS) and long COVID.

The landscape of healthcare is constantly evolving, with new research findings and innovative approaches emerging regularly. It is imperative that healthcare professionals stay informed about the latest evidence-based practices and incorporate them into daily routines, therefore enhancing the quality of care provided and ensuring the safety and well-being of patients.

There are longstanding practices that have been widely accepted in the past but have since been debunked or found potentially harmful. It is crucial that we collectively reevaluate and abandon these practices when necessary to prevent harm.

We would like to see national guidelines for New Zealand that follow international guidelines in both primary and secondary care. Standardising care with best practice guidelines eliminates the current postcode lottery for care occurring in our country, and ensures that every individual with ME/CFS, long COVID, and their common comorbidities, is dealt with appropriately, using the latest evidence-based information.

ANZMES has already produced two one-page documents covering pertinent information needed in primary care for diagnosis and management of ME/CFS and long COVID, and will produce guidelines for secondary care in due course.

The appropriate international guidelines for the diagnosis and management of ME are:

  • The Institute of Medicine 20151
  • Canadian Consensus Criteria (CCC)/International Consensus Criteria (ICC)2
  • Mayo Clinic Proceedings3
  • Centre for Disease Control and Prevention (CDC)4
  • National Institute for Health and Care Excellence (NICE)5

Why follow these Guidelines over others? 


Definitions and diagnosis of ME have advanced as clinical and biomedical understanding of the condition has increased and this is reflected in these guidelines. Over 20 different case definitions have been published with many containing inconsistencies between research and clinical criteria.  

In the past ME was misunderstood and physicians often labelled it as a psychological illness or a form of stress-induced fatigue. Excessively inclusive and inconsistent definitions and criteria initially created misconceptions about ME and led to negative experiences for people seeking diagnosis. For example, in 1991, a group of predominantly psychiatrists published criteria designed for research. This criteria was used for the PACE trial. They recognised a subgroup of people with chronic fatigue present with symptoms after infection. However, they did not exclude those with depression and anxiety, and factored this into the symptom definitions as “mood disturbance.” This has contributed to research in which participants may have had a mental health disorder causing fatigue, rather than ME.6 

As biomedical understanding has increased the diagnostic criteria have evolved,  in particular, to now recognise the multi-systemic nature of the condition and the impairment of the energy and recovery systems that result in Post Exertional Malaise (PEM).

The Institute of Medicine Criteria (IoM) and the International Consensus Criteria (ICC) are currently the most robust diagnostic criteria for clinicians. These set out three primary symptoms that must be present, for a minimum of six months to diagnose ME – PEM, unrefreshing sleep, and unexplained fatigue. At least one other additional symptom must be present – either orthostatic intolerance or cognitive impairment.  Functional impairment must be substantial, with ICC requiring 50% decrease in activity. Case definitions and criteria that do not include PEM, such as Fukuda 19947 are therefore now less commonly used in practice.

The International Consensus Criteria (ICC) was developed as a diagnostic tool for clinicians based on the Canadian Consensus Criteria (CCC). The CCC is considered the strictest criteria and is primarily used in research, superseding Fukuda.

When assessing a patient with a multitude of symptoms the IoM* criteria provide clarity in this process by offering a concise set of required symptoms. The IoM criteria published most recently (2015) are now widely considered to be the best tool for use in clinical settings as they offer a clearer definition than previous guidelines and emphasise the importance of the patient’s subjective experience and the need for thorough case taking and examination. The IoM (2015) can be used for both adults and children.

*IoM is now renamed National Academy of Medicine (NAM).

Symptom Management

Current best practice guidelines from robust unbiased reviews emphasise that all treatment needs to be offered in a way that avoids PEM and recommends that energy expenditure is managed within individual limits. Pacing for people with PEM has been shown to improve quality of life, fatigue severity, and physical functioning.8,9

What is PEM?

Post-Exertional Malaise is the worsening of ME or long COVID symptoms after physical or mental effort and this can happen one or two days after even minor activity.  PEM is also referred to as Post-Exertional Symptom Exacerbation (PESE) and Post-Exertional Neuroimmune Exhaustion (PENE). People with ME describe PEM as “crashing” or “collapsing” with relapse of symptoms.  It is helpful to understand that normally if a person is fatigued after exertion they will rest and then energy will be restored, in ME this physical recovery process is dysfunctional. Studies have identified differences in gene expression, blood volume and oxygen consumption, and mitochondrial function as some potential drivers for this dysfunction. Dysfunction of the regulatory control network within and between the nervous systems is also believed to contribute to the pathophysiology of PEM, which can impact all body systems.10,11 The most common symptoms associated with a PEM flare include body aches, pain, weakness, fatigue, cognitive dysfunction, and orthostatic intolerance.

What is Pacing?

Pacing is an energy management technique that can be used to help with symptoms related to PEM. Patients are encouraged to stay within their energy envelopes and gradually increase their activity levels over time if possible, while being mindful of their limits and symptoms.  The International Consensus Primer12 highlights the importance of patients learning to become aware of their bodies’ early warning signs that they are beginning to push themselves outside their limits. Useful tools include heart rate monitors, step counters, and temperature monitoring. For example, changes in heart rate (above anaerobic threshold) and reduction in body temperature can be early signals of overexertion.

There are three treatments that are not recommended for ME by international best practice guidelines (Mayo Clinical Proceedings, NICE, and CDC):

  • Cognitive Behavioural Therapy (CBT)
  • Graded Exercise Therapy
  • Lightning Process 

Why is Cognitive Behavioural Therapy Contraindicated as Treatment for ME?

Cognitive Behavioural Therapy (CBT) is not recommended as a treatment for ME by leading experts and organisations and is specifically contraindicated in international guidelines. These strategies do not recognise or address the underlying pathophysiological issues.13

While psychological approaches can be supportive they are not evidenced as treatments of the condition.14 There is no evidence to show that CBT can “cure” the physiological and cognitive impairment symptoms of ME and research has been offered to the media in a misleading context, which has led to an exaggerated perception of effectiveness.15 Further independent review has found that “the arguments that are used to claim that NICE was wrong, in reality, highlight the absence of evidence for the safety and efficacy of CBT and GET and strengthen the decision by NICE to drop CBT and GET as curative treatments for ME/CFS.”16

“When you develop therapies based on this psychogenic cognitive-behaviour theory, these therapies do not work, which raises the question of whether the theory works.”
Professor Brian Hughes, BA, EdM, PhD, Psychology Professor NUI Galway

The Mental Health and Addiction division of Manatū Hauora / Ministry of Health clearly stipulates that ME is a complex medical condition rather than a mental health condition (December 2022).

The pathophysiology of ME and Post Exertional Malaise (PEM)

The evidence for the pathophysiology underpinning ME,17 the harm that can result from PEM18 and the value of pacing as a primary strategy has proliferated in the past decade. Speculative theories of ME being associated with deconditioning, exercise avoidance, a somatic perception disorder, or unresolved trauma have been discredited.19,20 This shift from speculation to evidence is now reflected in numerous examples of peer-reviewed research, and in all reputable international guidance. 

Research in New Zealand, under Emeritus Professor Warren Tate and clinician Dr Rosamund Vallings (MNZM) offers insight into the biomedical basis identifying molecular changes in ME patients, including dysfunction of the autonomic nervous system, immune regulation, energy production and lowered general metabolism.21 Dysfunction of the regulatory control network within and between the nervous systems is also believed to contribute to the pathophysiology of PEM, which can impact all body systems.22,23 Further research suggests that PEM may be caused by an overactive immune response, leading to increased inflammation in the body. In a study published in the Journal of Translational Medicine, researchers found that ME patients with PEM and higher levels of pro-inflammatory cytokines in their blood, pointing to a potential immunological pathway.24 

In December 2022, the Ministry of Health supported the conclusions of the guidance for ME published by NICE (2021) saying ‘that ME/CFS is a serious and complex medical condition/disease with varying severity rather than a mental health condition and that there is not a primary psychological basis underlying its development and/or maintenance’.25

Why is Graded Exercise Therapy Contraindicated for ME?

Numerous reputable studies and guidelines including the IoM, NICE, Mayo Clinic and the CDC have removed Graded Exercise Therapy (GET) from treatment recommendations due to the potential that this strategy will elicit Post Exertional Malaise (PEM). This potential for harm extends to patients with Long COVID who experience Post Exertional Symptom Exacerbation (PESE), similar to PEM. 

Guidance that recommends GET and CBT has been withdrawn and replaced with pacing and aligned strategies:

  • The large 2011 PACE randomised trial26 which recommended GET and CBT has been robustly reviewed and discredited.27  Activities carried out as part of the PACE trial differ from what is considered “pacing.” Pacing is explained earlier in this document.
  • The Centers for Disease Control and Prevention removed CBT/GET from the treatment guidelines in 2017.28
  • Recommendation for CBT/GET originated from the 2007 NICE guidelines. However, these recommendations have now been withdrawn as they were based on nine (9) studies (4 CBT, 5 GET) each of which had significant methodological limitations. The 2021 NICE guidelines,29 DO NOT recommend CBT/GET and are based on 172 CBT and 64 GET study outcomes, which factored methodological limitations into the analysis. Arguments against the NICE review have been found to further highlight the lack of evidence of safety and efficacy for CBT and GET.30 Enclosed please find an explanation of the 2021 NICE review.
  • Consensus Recommendations31 published by Mayo Clinical Proceedings, in November 2021, recommended pacing as an individualised approach to energy conservation and management that can minimise the frequency, duration, and severity of PEM. In October 2023, Mayo Clinical Proceedings published a Concise Review for Clinicians for ME.32 This provides clear management advice stating that “Symptom-contingent pacing is recommended to all patients with ME/CFS.” 
  • The CDC and 2007 [and 2021] NICE guidelines cite pacing as an effective component in the treatment of patients with ME.
  • In 2019 and 2020, most Regional Health Pathways teams, in New Zealand, updated their clinical guidance for ME to reflect the IOM 2015 diagnostic criteria and the CDC’s recommendation to offer pacing rather than GET. 
  • Workwell foundation, a group of experts and researchers that work with fatigue-related illnesses, such as ME and Long COVID, oppose the use of GET for ME, explaining that GET “aimed at training the aerobic energy system, not only fails to improve function, but is detrimental to the health of patients and should not be recommended….Indications of metabolic dysfunction in ME/CFS suggest that limiting sustained activity whenever possible is a more reasonable therapeutic approach.” The Workwell Foundation’s  full argument and evidence can be found here in their Letter of Opposition to the use of GET for ME.

This also has implications for people with Long COVID as practitioners follow ME management for this condition, due to their similarities. Recent research comparing long COVID and ME/CFS found similarities that included the experience of low and medium physical and cognitive exertion to trigger PEM, symptoms of fatigue, pain, immune reaction, neurologic, orthostatic intolerance, and gastrointestinal symptoms during PEM, rest to recover from PEM, and benefits from pacing to prevent PEM.33 

The current Ministry of Health NZ Clinical Rehabilitation Guideline for People with Long COVID is aligned with ME/CFS management and states that for PEM or PESE: 

graded exercise therapy (GET: planned, regular exercise with incremental increases in frequency and/or intensity, duration and type with a goal to increase fitness) is not recommended for these people, because it can cause an exacerbation of symptoms. Symptom-led pacing is advocated for, this includes prioritising, planning, and use of an activity diary.34

Graded exercise therapy of planned regular exercise, with incremental increases usually utilises heart rate values, however individuals with ME often have chronotropic intolerance and therefore cannot achieve the same values to those individuals without this condition.35

Why is the Lightning Process not recommended for ME?

Best practice guidelines specifically state that the Lightning Process (LP) is not recommended as a treatment for ME, due to a lack of quality evidence and potential harms. 

Proponents of LP quote a single published study of the Lightning Process known as the SMILE trial. This study has been widely criticised for ‘outcome swapping’ as the primary outcome measure was changed from school attendance to scores on a self-report questionnaire. Given that LP overtly encourages patients to only report positive outcomes and improvement in their ability to control symptoms this is likely to lead to response bias. In July 2019, after an investigation by the Archives of Disease in Childhood, a lengthy and detailed editorial correction to the SMILE trial was published.36

The study corrections include, acknowledgement from the authors that the study was not fully ICMJE compliant, with their account of timeline and chronological order and changes being made to the primary outcomes of the study. 

While anecdotal stories indicate that these programmes do improve functionality for some, there are also reports that these programmes cause harm for others. Some people report severe, long term increases in symptoms following participation in these programmes when they have been encouraged to exceed their safe level of exertion. 

The Lightning Process is not cost-effective for many people with ME/CFS who are on low income/government benefits. Pacing, which is a self-management technique, is free, and can be carried out in one’s home. The only cost is if an individual chooses to purchase a wearable to monitor heart rate etc.

The World ME Alliance agrees with the international guidelines and published a position paper stating that: “The World ME Alliance and its members do not endorse the Lightning Process for people with Myalgic Encephalomyelitis (ME), sometimes called Chronic Fatigue Syndrome (CFS).”37

Given the lack of evidence for Lightning Process and aligned programmes, the claims of cure, the lack of informed consent provided to patients around the risk of PEM, and the potential for negative outcomes, it should not be promoted to, or recommended by, health professionals. 

Lived experience

The inclusion of consumers’ lived experiences is essential to the development and evaluation of health service delivery and to making quality improvements in the health system. The Health Quality and Safety Commission (HQSC) identifies that lived experience stories can help highlight where and how services could be improved to meet peoples’ needs. 

Narratives from members of the NZ ME/CFS community in the form of Case Studies have been obtained through the regional ME/CFS organisations to illustrate examples of harm that have occurred through misinformation and treatment recommendations for GET or the Lightning Process. They have not been included in this document as they are not peer-reviewed or published case studies, however these are available upon request.

Potential impact on the health of the community

Continuing to perpetuate these outdated recommendations may lead to harmful practice and teach new health practitioners to continue this. Inconsistencies between New Zealand medical practice teachings and international standards may also lead to confusion for new and emerging practitioners. 

There is great potential for harm because patients with ME who ignore or push through their symptoms can worsen their condition, often becoming bedridden.38 

Doctors with M.E state “Discriminatory practice and standards in research, clinical knowledge, and safety which would not be tolerated in any other disease areas have become normalised in the field of ME/CFS. However such practice is unlawful, harms patients, and generates risk.”39

As any good researcher or clinician should know, basing a theory or treatment regime, on one single study, is not good practice. Especially if the single study is known to be flawed and unreplicated. Studies must have sound methodology, high validity and reliability, and outcomes must be replicable. Even Randomised Control Trials (considered the most robust) can have flaws in methodology that affect outcomes, as demonstrated by the SMILE trial. It is imperative that health professionals and medical associations and schools use the growing body of research and knowledge to support its resources, take note of meta analyses and robust literature reviews, and only publish information that is supported by the evidence.

Using outdated and flawed studies for the basis of treatment programmes for healthcare in Aotearoa/New Zealand will undermine the reputation and authority of New Zealand medical professionals within the eyes of the international medical, clinician, and research communities. It makes it harder for New Zealand health professionals to be taken seriously on the international stage, if the country’s health policies and practices reflect outdated opinions and flawed studies.

The medical profession has a duty to uphold a standard of care that follows the Hippocratic oath of “first, do no harm” and it is vital that all publications produced by health professionals follow these standards, and those that are discredited, harmful, or outdated are removed from circulation. 

We welcome the opportunity to work with you to ensure that any publications disseminated by health professionals or associations, follow the latest reputable research and guidelines. Our team of world-renowned experts are at the forefront of ME/CFS research and clinical practice and as the National Advisory on ME, ANZMES is fully equipped to provide the resources necessary to ensure that only the appropriate information is made available nationwide. Please utilise our expertise, on a subject that we spend 100% of our time researching, analysing, representing, and educating on, to ensure that best practice guidelines are the ONLY guidelines released by any Aotearoa/New Zealand based medical entity or representative.

We look forward to your positive response.

Yours sincerely

Fiona Charlton

President, ANZMES

Organisations in support of this letter:

M.E. Awareness NZ

Complex Chronic Illness Support

ME Support – NZ

MECFS Canterbury

MECFS MEISS (Otago and Southland)

Rest Assured Respite Trust

World ME Alliance

Emerge Australia

The ME Association (MEA)

Solve M.E.

Clinicians and Researchers in support of this letter:

Aotearoa/New Zealand

Emeritus Professor Warren Tate, University of Otago

Dr. Rosamund Vallings, MNZM

Dr. Anna Brooks, University of Auckland

Dr. Sarah Dalziel

Dr. Cathy Stephenson

Dr. Ken Jolly

Dr. Judijke Scheffer

Dr. Lynette Hodges, Massey University

Assoc. Professor Mona Jeffreys, Victoria University


Professor Sonya Marshall-Gradisnik, NCNED Professor

Dr. Charles Shepherd, MEA

Professor Leonard Jason, de Paul University

Professor Maureen Hanson, Cornell


1 Institute of Medicine of the National Academies. Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness.2015.

2 Carruthers BM, van de Sande MI, De Meirleir KL, Klimas NG, Broderick G, Mitchell, et al. Myalgic Encephalomyelitis: International Consensus Criteria. Journal of Internal Medicine. 2011 doi: 10.1111/j.1365-2796.2011.02428.x. (published online on 20 July 2011)

3 Diagnosis and Management of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. 2023. Mayo Clinic Proceedings.

4 Centers for Disease Control and Prevention. (2022). Information for Healthcare Providers. Understanding History of Case Definitions and Criteria.

5 National Institute for Health and Care Excellence (NICE). (2021). ‘Overview | Myalgic Encephalomyelitis (or Encephalopathy)/Chronic Fatigue Syndrome: Diagnosis and Management | Guidance | NICE’. NICE.

6 Sharpe, M.C. et. al. (1990) A report – chronic fatigue syndrome: guidelines for research

7 Fukuda K, Straus SE, Hickie I, Sharpe MC, Dobbins JG, Komaroff A. (1994). The chronic fatigue syndrome: A comprehensive approach to its definition and study. Annals of Internal Medicine. 1994;121:953–959.

8 Jason L, Benton M, Torres-Harding S, Muldowney K. The impact of energy modulation on physical functioning and fatigue severity among patients with ME/CFS. Patient Educ Couns. 2009;77(2):237-241. doi:10.1016/j.pec.2009.02.015  

9 Bested AC, Marshall LM. Review of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: an evidence-based approach to diagnosis and management by clinicians. Rev Environ Health. 2015;30(4):223-249. doi:10.1515/reveh-2015-0026

10 Tirelli U, Chierichetti F, Tavio M, Simonelli C, Bianchin G, Zanco P, Ferlin G. Brain positron emission tomography (PET) in chronic fatigue syndrome: preliminary data. Amer J Med 1998; 105(3A): 54S-58S. [PMID: 9790483]

11 De Lange F, Kalkman J, et al. Gray matter volume reduction in the chronic fatigue syndrome. Neuroimage 2005; 26: 777-81. [PMID: 15955487]

12 Carruthers B. M. & van de Sande M. I. (2021). Myalgic Encephalomyelitis – Adult & Paediatric: International Consensus Primer for Medical Practitioners.

13  Twisk and Maes (2009)

14 Doctors with ME

15 ‘Are the New NICE Guidelines for ME/CFS at Odds with the Research Evidence?’, 14 August 2022.

16 Vink M, Vink-Niese A. The Updated NICE Guidance Exposed the Serious Flaws in CBT and Graded Exercise Therapy Trials for ME/CFS. Healthcare (Basel). 2022 May 12;10(5):898. doi: 10.3390/healthcare10050898. PMID: 35628033; PMCID: PMC9141828.

17 ME/CFS and Long COVID share similar symptoms and biological abnormalities: road map to the literature. 2023. Frontiers in Medicine.

18 Treatment Harms to Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. 2022. Advances in Bioengineering & Biomedical Science Research. DOI: 10.33140/ABBSR.06.01.01

19 Geraghty K, Jason L, Sunnquist M, Tuller D, Blease C, Adeniji C. The ‘cognitive behavioural model’ of chronic fatigue syndrome: Critique of a flawed model. Health Psychol Open. 2019 Apr 23;6(1):2055102919838907. doi: 10.1177/2055102919838907. PMID: 31041108; PMCID: PMC6482658.

20 van Campen CLMC, Rowe PC, Visser FC. Deconditioning does not explain orthostatic intolerance in ME/CFS (myalgic encephalomyelitis/chronic fatigue syndrome). J Transl Med. 2021 May 4;19(1):193. doi: 10.1186/s12967-021-02819-0. PMID: 33947430; PMCID: PMC8097965.

21 Sweetman E, Ryan M, Edgar C, MacKay A, Vallings R, Tate W. (2019). Changes in the transcriptome of circulating immune cells of a New Zealand cohort with myalgic encephalomyelitis/chronic fatigue syndrome. Int J Immunopathol Pharmacol. 33:205873841882040.

22 Tirelli U, Chierichetti F, Tavio M, Simonelli C, Bianchin G, Zanco P, Ferlin G. Brain positron emission tomography (PET) in chronic fatigue syndrome: preliminary data. Amer J Med 1998; 105(3A): 54S-58S. [PMID: 9790483]

23 De Lange F, Kalkman J, et al. Gray matter volume reduction in the chronic fatigue syndrome. Neuroimage 2005; 26: 777-81. [PMID: 15955487]

24  Ghali, A., Richa, P., Lacout, C. et al. Epidemiological and clinical factors associated with post-exertional malaise severity in patients with myalgic encephalomyelitis/chronic fatigue syndrome. J Transl Med 18, 246 (2020).

25 Letter from Ministry of Health. 19 Dec 2022.

26 Comparison of adaptive pacing therapy, cognitive behaviour therapy, graded exercise therapy, and specialist medical care for chronic fatigue syndrome (PACE): a randomised trial. 2011. Lancet.

27 Rethinking the treatment of chronic fatigue syndrome—a reanalysis and evaluation of findings from a recent major trial of graded exercise and CBT. 2018. BMC Psychology.

28 CDC Treating the Most Disruptive Symptoms First and Preventing Worsening of Symptoms, 2021.

29 National Institute for Health and Care Excellence (NICE). (2021). ‘Overview | Myalgic Encephalomyelitis (or Encephalopathy)/Chronic Fatigue Syndrome: Diagnosis and Management | Guidance | NICE’. NICE.

30  Vink M, Vink-Niese A. The Updated NICE Guidance Exposed the Serious Flaws in CBT and Graded Exercise Therapy Trials for ME/CFS. Healthcare (Basel). 2022 May 12;10(5):898. doi: 10.3390/healthcare10050898. PMID: 35628033; PMCID: PMC9141828.

31  Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Essentials of Diagnosis and Management. 2021. Mayo Clinical Proceedings. L Bateman, et al.

32  Diagnosis and Management of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. 2023. Mayo Clinic Proceedings.

33 Vernon, Suzanne D. et al. ‘Post-exertional Malaise Among People with Long COVID Compared to Myalgic Encephalomyelitis/chronic Fatigue Syndrome (ME/CFS)’. 1 Jan. 2023 : 1 – 8.

34  Ministry of Health. 2022. Clinical Rehabilitation Guideline for People with Long COVID (Coronavirus Disease) in Aotearoa New Zealand: Revised December 2022. Wellington: Ministry of Health.

35 Davenport, Todd E. et al. ‘Chronotropic Intolerance: An Overlooked Determinant of Symptoms and Activity in Myalgic Encephalomyelitis / Chronic Fatigue Syndrome. Frontiers Paed. 22 Marc. 2019, 7

36 Editor’s note on correction to Crawley et al. (2018).

37 World ME Alliance. 2022. The Lightning Process – A Position Paper.

38 Strassheim, Victoria; Newton, Julia L.; Collins, Tracy (February 5, 2021). “Experiences of Living with Severe Chronic Fatigue Syndrome/Myalgic Encephalomyelitis”. Healthcare. 9 (2): 168. doi:10.3390/healthcare9020168. ISSN 2227-9032. PMC 7914910. PMID 33562474.

39 Doctors with-ME. ”Rights and Obligations in ME/CFS: Overcoming normalised disregard for standards”

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