Thanks for that and for all your work on this--it's pretty amazing.
Thank you!
So a "secondary parenting" means placing an illness under another rubric as well as its primary one--ie under neurology as well as mental disorders chapter?
Yes. Multiple parenting wasn't permissible under previous editions of ICD.
For ICD-11, some disorders and diseases have been assigned a secondary and occasionally a tertiary parent. This function should not be referred to as "dual parenting", "co-parenting" or "dual classification" as there is always a "primary parent" (aka the "linearization parent") and it is the primary parent's chapter location that dictates what code is assigned to the category and it retains that code wherever it may be secondary listed.
Where a secondary parent has been assigned, the disorder or disease may be listed under two discrete parent classes within the same chapter or straddle more than one chapter. This enables, for example, diseases like skin cancers to be listed and searchable under both the chapter for
Diseases of the skin and the chapter for
Neoplasms.
A good example of tertiary parenting is Behçet disease, which is listed under two parent classes within the
Diseases of the immune system chapter and is also listed under
Diseases of the skin.
In 2010, ICD Revision published a discussion paper proposing the concept of a potential new chapter for ICD-11 specifically for multi-system diseases like Behçet disease, which straddle more than one organ system or more than one aetiology chapter. The concept of creating a Multi-system chapter for certain diseases was later rejected in preference to specifying secondary and tertiary parents within the existing chapter structure.
The secondary parenting of
Dissociative neurological symptom disorder and its subclasses under the Neurology chapter was implemented in May 2018.
...And under neurology, it retains the dissociative name rather than "functional"?
Yes.
Dissociative neurological symptom disorder's primary parent chapter is Chapter 06
Mental, behavioural or neurodevelopmental disorders. Its primary parent location is under the
Dissociative disorders category block, so it takes its code from that parent class and is coded:
6B60 Dissociative neurological symptom disorder.
Under
6B60 Dissociative neurological symptom disorder sit 15 discretely coded for subclasses (codes
6B60.0 to
6B60.85) for greater specificity, for example:
6B60.4 Dissociative neurological symptom disorder, with non-epileptic seizures and
6B60.6 Dissociative neurological symptom disorder, with paresis or weakness.
So within ICD-11 there are 15 discrete DNSD codes that can be selected for, and all are prefaced by "Dissociative".
Where the terms are listed under the Neurology chapter, they retain the same category names, so no, they don't drop "Dissociative" under their Neurology chapter listing.
However, the terms
- Functional neurological disorders
- Functional neurological symptom disorder
- Conversion disorder
are listed under Synonyms under the
6B60 Dissociative neurological symptom disorder category and are indexed to the 6B60.Z "Residual" code. But the ICD-11 "Concept Title" or "Preferred Term" is
"Dissociative neurological symptom disorder".
So the idea is WHO rejected the use of "functional" because they thought it blurred the lines too much when this was still really the same old dissociative or conversion disorder? What are the implications of having it co-listed under neurology? And under neurology, it retains the dissociative name rather than "functional"?
The WHO rejected "functional" for a number of reasons:
a) The APA's DSM-5 code sets are copyright and APA publishing derives a substantial income stream from licensing the use of its code sets for research criteria and from sales of its DSM-5 and derivative publications for clinical and reimbursement use. Its criteria set for "Conversion disorder (Functional neurological symptom disorder)" are a rigid set of criteria which can be used in clinical and research settings. Whereas ICD-11 does not use rigid criteria sets, but more flexible disorder descriptions, required features etc.
If the WHO had wanted to call its ICD-11 category "Functional neurological symptom disorder" (ie give it the same disorder name as the DSM-5 disorder) that would have presented licensing issues with APA publishing. Similarly, if the external working group that developed "Bodily distress disorder" had wanted to call their similar construct "Somatic symptom disorder" there would have been intellectual property and licensing issues; and having a DMS-5 version of SSD and slightly different or a significantly different ICD-11 variation on SSD could present problems clinically and for research.
b) TAG Mental Health has said:
"The Mental Health TAG preferred to avoid the term ‘functional’ in the entity title as within mental health this term is often seen as dated and sometimes as pejorative. Instead, the term ‘dissociative’ was retained in order to anchor them clearly in the dissociative disorders grouping. There is no rationale or evidence presented in this proposal [from Stone et al] based on which to override this decision. MSAC recognizes that the symptoms presented as a part of this disorder are by definition not due to a disease of the nervous system, but they mimic neurological symptoms and patients with these presentations are commonly referred to neurologists for evaluation."
The word "functional" is also used in ICD in relation to general medical conditions where it has a number of meanings. The WHO publication
International Classification of Functioning, Disability and Health (ICF) (the WHO framework for measuring health and disability at both individual and population levels) also uses the term "functional" in the context of "functional impairment" "functioning" and disability.
What WHO and TAG Mental Health do not do is set out what they currently understand by the term "Dissociative" which is a legacy term carried forward from ICD-10. So I cannot determine whether the WHO conceptualises "Dissociative" as "the same old dissociative or conversion disorder" or whether its conceptualisation of the term has evolved over the years.
Do bear in mind that the brief disorder descriptions you see in the Blue and Orange browsers for these 15 DNSD categories are not the full disorder descriptions and guidelines. For these we need to wait for the
Clinical Descriptions and Diagnostic Guidelines (CDDG) for ICD‐11 Mental, Behavioural and Neurodevelopmental Disorders to be finalized and published.
The CDDG provides the expanded clinical descriptions, essential (required) features, boundaries with other disorders and normality, differential diagnoses, additional features, culture-related features and codes for all mental and behavioural disorders commonly encountered in clinical psychiatry; it is intended for mental health professionals and for general clinical, educational and service use. (I have a non public domain draft of how the CDDG stood in 2016 for these terms, though the codes and category names and possibly some of the draft texts will have been revised since 2016.)
The change of disorder name from
Dissociative disorder of movement, sensation, or cognition to
Dissociative neurological symptom disorder was implemented in October 2017. There is currently a proposal submitted by an external stakeholder to revert back to Dissociative disorders of movement, sensation or cognition. This proposal is currently with the CSAC for a decision.
What are the implications of having it co-listed under neurology?
In my opinion, the secondary parenting of the DNSD disorder term and its 15 subclasses under Neurology will not impact significantly. There might potentially be some advantage to patients and clinicians in the areas of commissioning of services, access to specialities, and reimbursement. But the primary parent code and primary linearization parent remain firmly tethered to the Mental disorder chapter.
In the ICD-11 browser the secondary parent is displayed thus:
But click on the
category's link as listed in the Neurology chapter's hierarchical listings on the left of the screen and users are redirected back to the listing in its primary parent location in the Mental disorders chapter. (Although the 15 subclasses don't jump link back to their primary location in the Mental disorders chapter with the Foundation Component tab selected, they do redirect in the MMS Linearization view - which is the ICD-11 equivalent to the Tabular List).
(These DNSD subclass categories are "grayed out" in the Neurology chapter's MMS Linearization, which indicates that these terms are primary parented elsewhere in the classification.)
In the Coding Tool/Index, with the Chapter distribution/filter button selected, only the Mental and behavioural chapter is listed. As with the ICD-10 Index, the Coding Tool is presented as the first point of access for coders.
In practice, I suspect clinicians and coders will be largely oblivious to DNSD's secondary parenting under Neurology, and as I say, this was a grudging concession by TAG Mental Health after several years of "tug-of-war" across the two chapters between TAG Mental Health and the clinical professional neurology lobby group (one of whom was chair of TAG Neurology and a past President of the World Federation of Neurology).
In my opinion it is tokenism on the part of WHO and is perceived as such by at least one leading FND patient group.
Try reading the cited paper.