The Elephant in the Room Series Two: ICD-10 Version for 2006 Volume 3 Alphabetical Index


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APA    DSM    DSM-IV    DSM-V    WHO    ICD    ICD-10    ICD-11    American Psychiatric Association    Diagnostic and Statistical Manual of Mental Disorders    World Health Organization    Classifications    DSM Revision Process    DSM-V Task Force    DSM-V Somatic Distress Disorders Work Group    Somatic Symptom Disorders Work Group    DSM-ICD Harmonization Coordination Group    International Advisory Group    Revision of ICD Mental and Behavioural Disorders    Global Scientific Partnership Coordination Group    ICD Update and Revision Platform    WHO Collaborating Centre    CISSD Project    MUPSS Project    Somatoform    Somatisation    Somatization    Functional Somatic Syndromes    FSS    MUS    Myalgic encephalomyelitis    ME    Chronic fatigue syndrome    CFS    Fibromyalgia    FM    IBS    CS    CI    GWS


The Elephant in the Room Series Two:

ICD-10, 10th Revision Version for 2006, Volume 3 Alphabetical Index

On 17 June, I received a communication from the Legal Compliance Officer for the Institute of Psychiatry, King’s College London, in which I was advised:

“Dr Sykes’ original report, which was submitted to Action for ME and the Hugh and Ruby Sykes Charitable Trust, contained an inaccuracy, as has been previously discussed (since Chronic Fatigue Syndrome [CFS] is not listed in the main list of neurological disorders in Vol. I of ICD-10, the original report stated, wrongly, that there was no mention of CFS in ICD-10. In fact there is a mention of CFS in Vol.3, the Index).”

“…This inaccuracy was brought to the attention of Action for ME and the Hugh and Ruby Sykes Charitable Trust. The summary report (sent to you on 2 June) corrects the inaccuracy, and has been communicated to them. Dr Sykes believes that this inaccuracy makes no substantial difference to the conclusions of the report.”

This statement from Legal Compliance confirms that the unofficial CISSD Project was initiated, funded, administered and supported by Action for M.E. and co-ordinated by Dr Richard Sykes on the premise that there was no mention of Chronic Fatigue Syndrome in ICD-10.

A copy of ICD-10 Volume 3 Alphabetical Index, to which the Institute of Psychiatry’s Legal Compliance Officer refers, can be accessed, via Scribd at:


International Statistical Classification of Diseases and Related Health Problems

10th Revision Version for 2006

Volume 3 Alphabetical Index

(770 pages For the entry in question, see page 528, top right hand column)

The following documents are also available from the same page:

ICD 9-CM 2005

ICD-10 2006 Tabular List

Standard Coding Guideline ICD-10-TM 2006

ICD-10 [Update 2007]


This statement in the original December 2007 CISSD Project report:

“Despite claims to the contrary, the classification of CFS is still an open issue. CFS and CFS/ME are not mentioned either in the latest edition of ICD (ICD-10), or in the latest edition of DSM (DSM-IV).”

was amended in the “Summary report” provided by Dr Sykes to the ME Association (published 3 June 2009) to read:

2.2 Somatoform Disorders, the International Classifications and CFS

There are still problems associated with the classification of CFS. It is true that CFS is listed under “syndrome” in Volume III, the Index, of ICD-10 and placed in G93.3, a category of neurological illness. But there remain the problems:

“(1) some psychiatrists and others contest this classification of CFS as a neurological disorder,

(2) “fatigue syndrome” is listed in ICD-10 as F48, a mental disorder – which creates the apparent anomaly that “fatigue syndrome” is a mental disorder, but “chronic fatigue syndrome” is a neurological disorder, and

(3) the classification of CFS as a neurological disorder does not seem to be fully integrated into ICD-10.

As far as I have discovered this seems to be the only reference to CFS in all the relevant ICD -10 volumes. For example, CFS is not mentioned in main Volume 1, the Tabular List, of ICD-10 – where one would expect it to be – nor is it included in the current (2007) online version of ICD-10.

It is also true that the WHO gave permission in 2004 for the UK adaptation of the WHO primary care management and diagnostic guidelines on mental health, which in this edition expanded to include some common neurological conditions. This edition of the good practice diagnostic and management guidelines follows the ICD-10 Index code for CFS as G93. It remains to be seen, however, whether this practice will be followed in ICD-11.”

The “Summary report” on the CISSD Project, published by the ME Association on 3 June, can be read here:


The “Summary report” drew upon content in the December 2007 report provided to Action for M.E. at the end of the Project’s life. But some sections are worded differently and Appendix B in the December 2007 report does not appear at all in the document that has been published by the ME Association.

The full December 2007 report for Action for M.E. can be read here:

The CISSD Project and CFS/ME, Report on the CISSD Project (Conceptual Issues in Somatoform and Similar Disorders) for Action for ME Richard Sykes
December 2007


I include some extracts, below, including the missing Appendix B, followed by a brief commentary:


CFS and the International Classifications


Despite claims to the contrary, the classification of CFS is still an open issue. CFS and CFS/ME* are not mentioned either in the latest edition of ICD (ICD-10), or in the latest edition of DSM (DSM-IV).**

[*Ed: The WHO does not use the composite term “CFS/ME” and describes NICE’s use of this term as “unfortunate”. **This statement was revised in the “Summary report” published by the ME Association, as set out, above.]


It is true that in 2004 permission was given by the WHO for the UK to adapt the WHO classification for the purposes of Primary Care in the UK and that on this basis a classification has been produced for use in the UK which lists CFS and CFS/ME as a neurological disorder. While many consider that this is a step in the right direction, this classification is a UK adaptation only and has not been formally adopted by the WHO. It has no validity in other countries. No formal decision has yet been made by the WHO and it is still an open question what the official WHO classification of CFS and CFS/ME will be in the next revision. (See also App B.)

[Ed: This statement was also revised in the “Summary report” published by the ME Association, see above.]


In addition to coordinating the CISSD project and taking part in the CISSD workshops, my own activities have included travel to meet the main international figures involved in these issues and the organization of a separate workshop on CISSD topics as part of an international conference in Croatia. In addition I gave two presentations at that workshop and further presentations at two other international conferences (in Germany and The Netherlands) and at professional conferences in London*, Oxford and Leeds (See App C). I have also produced the co-ordinator’s report on the project.

[Ed: *Melvin Ramsay Society Meeting, April 2007, attended by Dr Charles Shepherd, ME Association, who also gave a presentation. The presentation given by Dr Richard Sykes: “Conceptual Issues in the Classification of ME/CFS” and the Meeting Agenda were advertised by the ME Association on their website.]


While it is not a foregone conclusion that in the next international revisions CFS will be classified as a “general medical condition” or physical disorder and not as a mental disorder, the CISSD project will increased the likelihood that CFS and CFS/ME* will be so classified.

[*Ed: WHO ICD does not use the composite term CFS/ME.]


[Ed: Notes 1-3 do appear in the June ’09 “Summary report” published by the ME Association but are included here, for context.]


Note 1, I am most appreciative of the help given by Professor John Bradfield, former Professor of Histopathology at Bristol University, in compiling this report. In addition, he has made numerous other most valuable contributions as Project Advisor to the CISSD Project.

Note 2. There are, most confusingly, a few exceptions to this rule in ICD-10. For example, Irritable Bowel Syndrome is classified both as a disorder of the Digestive System (K 58) and as a Somatoform Autonomic Function Disorder (F45.32) – a mental disorder.

Note 3. The situation is more complex in ICD-10, since ICD-10 includes, besides Somatoform Disorders, a further possible pigeonhole for CFS/ME. This is the subcategory of “Neurasthenia” which ICD-10 includes in addition to the category of Somatoform Disorders. While the project did not specifically address the problems associated with Neurasthenia, there are some strong objections to the subcategory of Neurasthenia and it is possible that this subcategory will be omitted in the next revision of ICD-10.

CFS and CFS/ME are not listed in ICD-10* and of the 4 related conditions that are listed (post-viral fatigue syndrome, benign myalgic encephalomyelitis, neurasthenia, fatigue syndrome), 2 are listed as neurological disorders and 2 as mental disorders. On the one hand “post-viral fatigue syndrome” is classified as a neurological disorder with the code number G33.3 [sic]. In CDDG this is said to include “benign myalgic encephalomyelitis”. Although the adjective  “benign” has long since been dropped and although most users of the term ME now say that ME should stand for Myalgic Encephalopathy, rather than Myalgic Encephalomyelitis** (since there is no evidence of encephalomyelitis), this would appear to be a good reason for saying that ME is implicitly classified as a neurological disorder. (Since G33.4 [sic] is the code for encephalopathy, it would seem that this code rather than G33.3 [sic] is now the more appropriate code for ME.***)


Appendix B How does the WHO currently classify CFS/ME?

“CFS/ME” (Chronic Fatigue Syndrome/Myalgic Encephalomyelitis or Myalgic Encephalopathy) is the composite name used by the UK Department of Health and other organizations to refer to a condition that has been named and defined in a variety of ways. Generally speaking, “CFS” tends to be preferred by health professionals, “ME” by patients.


The main WHO (World Health Organization) classification of diseases and disorders is the International Statistical Classification of Diseases and related Health Problems (ICD). This classification is a classification of all disorders and related health problems and contains one chapter, chapter V, which is concerned solely with “mental and behavioural disorders”. The classification is revised periodically: the latest revision is the tenth revision (ICD-10) which was published in 3 volumes; Vol P A Tabular List in 1992, Vol 2: Instruction Manual in 1993 and Vol 3: Index in 1994.

Also produced from 1992 onwards was a separate series of volumes that dealt solely with mental and behavioural disorders, the subject of chapter V of ICD. Although the glossary provided by chapter V of ICD was considered adequate for use by coders or clerical workers, it was not recommended for use by health professionals. The first and central volume of the additional series was The ICD-10 Classification of Mental and Behavioural Disorders. Clinical descriptions and diagnostic guidelines (CDDG), produced in 1992, which was intended for general clinical, educational and service use. (Other volumes in this series included The ICD-10 Classification of Mental and Behavioural Disorders. Diagnostic Criteria for Research (DCR), and Diagnostic and Management Guidelines for Mental Disorders in Primary Care; ICD-10 Chapter V Primary Care Version.)

Is CFS/ME classified as a neurological or as a mental disorder in ICD-10?

[Ed: *This statement has been corrected in the “Summary report” published by the ME Association.

**Dr Sykes provides no supporting evidence for this statement.

***Dr Sykes provides no medical evidence to support his proposal that it would be more appropriate for “Myalgic Encephalopathy” to be classified at the same coding as “Encephalopathy” (G93.4), rather than at G93.3, where “Benign myalgic encephalomyelitis” has been coded for many years.]

On the other hand “neurasthenia” is classified as a neurotic disorder with the code number F48.0 and CDDG states that this includes “fatigue syndrome”. So it could be argued that CFS should be classified as a neurotic, and hence, a mental disorder. A case could also be made for coding some cases of CFS as F45 Somatoform Disorders, either as F45.1, the code for Undifferentiated Somatoform Disorder or as F45:3, the code for Somatoform Autonomic Dysfunction, or as F45.9, the code for Somatoform Disorder, Unspecified. All these are codes for mental disorders.

This presents a problem for CFS/ME. If ME is stressed, then it could be argued that CFS/ME should be classified as a physical disorder, since benign myalgic encephalomyelitis is classified as a neurological disorder. On the other hand, if Chronic Fatigue Syndrome is stressed then it could be argued that CFS/ME should be classified as a mental disorder, since fatigue syndrome is classified as a neurotic disorder.

Developments since 1992

In 2004 the WHO Guide to Mental and Neurological Health in Primary Care, Second Edition, was published by the Royal Society of Medicine Press. This was described on the cover and in the frontispiece as “Adapted for the UK, with permission, from Diagnostic and Management Guidelines for Mental Disorders in Primary Care: ICD-10 Chapter V Primary Care Version”.

In this volume the main term used is Chronic Fatigue Syndrome (CFS), which is said to be also referred to as ME (Myalgic Encephalomyelitis or Myalgic Encephalopathy) or as CFS/ME, and this is coded as G93.3. G.93.3 is the code for post-viral fatigue syndrome, a neurological disorder.

So does this settle the matter? Is CFS/ME now officially classified by the WHO as a neurological, not as a mental disorder?

Unfortunately the matter is not quite so simple, for a number of reasons. In the first place the 2004 publication is described as “adapted for the UK, with permission”. This means that it is not applicable in countries outside the UK, in Germany or France etc.. It does not have international applicability. Secondly, even in the UK it applies only to Primary Care (GP level). It does not claim to be applicable to Secondary Care (hospital level).

Thirdly, even in the UK it does not claim to be an official WHO classification. It is an initiative of the UK WHO Collaborating Centre, one of many of the Collaborating Centres worldwide, and is backed by the English Department of Health and a number of other organizations and individuals. It is not an authoritative WHO classification but is intended simply to provide helpful recommendations which UK GPs may use or not use as they wish. In the UK a GP may use any of a number of competing classifications. These include the International Classification of Health Problems in Primary Care (ICHPPP), the Read Codes, and a triaxial classification. They can also choose not to use a classification system at all.


“CFS” and “CFS/ME” are not listed in ICD-10 and this leaves room for debate as to how they should be listed. The UK WHO Collaborating Centre, with the support of the Department of Health and other organizations, proposed in 2004 that they should be coded as G33.3 [sic], the code for a neurological disorder. These proposals are undoubtedly encouraging for the ME patients’ organizations, who will hope that this initiative will be confirmed in the next revision of ICD-10, but they are not yet official recommendations by the WHO. There remains confusion and debate about how CFS/ME fits in to the official WHO classification.

A note on DSM-IV.

DSM-IV is the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, produced by the American Psychiatric Association. It has been extensively researched and is in widespread use worldwide.

In DSM-IV there is equally no mention of CFS, but neurasthenia is mentioned and is subsumed under Undifferentiated Somatoform Disorder, one of the Somatoform  Disorders. There is an extensive overlap between the symptoms of neurasthenia and of CFS and consequently some argue that this is where CFS should be placed. Against this it could be argued that CFS or ME or CFS/ME should be classified as G93.3 in ICD and hence should not have a place in a manual of mental disorders at all.

So for DSM-IV, too, there is the same uncertainty as to how CFS/ME should be classified.

[Extracts end]

Since the WHO doesn’t use and doesn’t like the composite term “CFS/ME” – it’s all rather muddled, isn’t it? And when presenting to the Ramsay Society meeting, in 2007, around the work of the CISSD Project, Dr Sykes used “ME/CFS”.

Read the review paper published by the CISSD Project leads in July 2007 (Psychosomatics) and you would not know that ME existed as a term in ICD; there is not a single mention of “CFS/ME” or “ME/CFS” or of existing ME and PVFS codings, because ICD and ICD codings are not mentioned at all, and “chronic fatigue syndrome” is only mentioned in passing as one of the so-called “Functional Somatic Syndromes”.

But the Project was described by Action for M.E. in 2006 as the “WHO Somatisation Project” and that “This grant is provided to help lobby the World Health Organisation for the recognition of M.E. and its re-catergorisation as a physical illness”.

What did Action for M.E. understand by that statement? What does it understand, now?

Dr Sykes has published no commentary on the most recent proposals of the DSM-V Somatic Symptoms Disorders Work Group.

In addition to the misconception around Volume 3, there are also other errors in the December 2007 report to Action for M.E. There are several instances in Appendix B where “G33.3” and “G33.4” have been used where this should have been “G93.3” and (presumably) “G93.4” (the classification code for Encephalopathy).

When Dr Sykes provides the Institute of Psychiatry’s Legal Compliance Officer with an authorised version of the text of the December 2007 report in order to  fulfil my outstanding request for information under the FOI Act, it is hoped that Dr Sykes will have acted on my suggestion that the document is accompanied by a Erratum Notice which addresses the errors and misconceptions in his original report.

One of the recommendations of the CISSD Project workgroup was support for the APA and WHO’s commitment “…to facilitate the achievement of the highest possible extent of uniformity and harmonization between ICD-11 mental and behavioural disorders and DSM-V disorders and their diagnostic criteria” with the objective that “the WHO and APA should make all attempts to ensure that in their core versions, the category names, glossary descriptions and criteria are  identical for ICD and DSM.”

It is worth noting that alliances of rare diseases patient organisations are already actively engaged in dialogue with  the ICD Rare Diseases Topic Advisory Group as it works on its proposals towards ICD-11.

But we have two chapters of ICD-11 to monitor – Chapter VI (G93.3 codes) and Chapter V: Mental and Behavioural Disorders (F45-F48 codes).

The chapter on ICD Mental and Behavioural Disorders is to be harmonized with DSM-V.

The target date for the release of DSM-V is 2012 and some field trials are expected to start this summer.

How many of our UK and international ME advocacy groups, patient organisations,  ME clinicians and researchers are currently engaged in dialogue with the APA and the WHO over the revisions of these complex and enmeshed classification systems?


For the most recent update on the progress of the DSM-V Somatic Symptom Disorders Work Group:

For a more expansive report on the progress of this Work Group:

The proposed diagnosis of somatic symptom disorders in DSM-V to replace somatoform disorders in DSM-IV – a preliminary report  Journal of Psychosomatic Research, Editorial: June 2009
Joel Dimsdale and Francis Creed on behalf of the DSM Workgroup on Somatic Symptom Disorders

(See section: “Psychological factor affecting general medical condition”)

For The Status of the CISSD Project unscrambled: /

For WHO statement on the use of the composite term “CFS/ME” see paragraph eight:
ME/CFS: TERMINOLOGY, Margaret Williams, 27 April 2009

Psychiatric Times  maintains a page of resources for the current edition of DSM, DSM-IV, with updates, articles and commentary around the development of DSM-V.