Neurocognitive disorders in ICD‐11: a new proposal and its outcome
Authors: Wolfgang Gaebel, Geoffrey M. Reed, Robert Jakob
Journal: World Psychiatry (2019)

The appropriate classification of diseases involving neurocognitive impairment has been an area of professional dissent between psychiatry and neurology for the past several years. This has been reflected in the groupings of “neurocognitive disorders” in chapter 6 on mental disorders and “disorders with neurocognitive impairment as a major feature” in chapter 8 on diseases of the nervous system in the draft version of the ICD-11. The disagreement about the placement of dementias in ICD-11 has been settled by international consensus after the intervention of several scientific associations in the mental health field1, with the dementia categories being included in chapter 6 and their underlying causes being represented in chapter 8, following the logic of ICD-10. In August 2018, a group of neurologists posted on the ICD-11 website a “complex hierarchical changes proposal” to replace “vascular dementia” with “vascular cognitive impairment” (VCI)2. Referring to the publication of a “primer”3, VCI was defined as “the contribution of vascular pathology to any severity of cognitive impairment, ranging from subjective cognitive decline and mild cognitive impairment to dementia” . In essence, the proposal argued that the term “vascular dementia” in chapter 6 had become “obsolete” and should be replaced by VCI in chapter 8. The stated rationale3 was that “vascular pathology is common in the elderly with and without cognitive decline… mostly caused by a mixture of degenerative brain pathology in association with ischemia…; this requires detailed neurological and imaging workup and will forever preclude the diagnosis of ‘vascular dementia' without proper investigations” . The proposal concluded: “We also suggest to our colleagues dealing with the mental health chapter 6 to reconsider their definition of vascular dementia. It is crucial that ICD-11 truly reflects modern 21st century thinking and practice”. After consultation with the World Health Organization (WHO), a roundtable discussion with invited psychiatric experts was organized at the World Congress of Psychiatry in Mexico City in September 2018. A consensus was reached to post a critical commentary after endorsement by a larger group of experts representing a variety of national and international scientific psychiatric associations4. In conclusion, the implementation of a new category of VCI in chapter 8 seems premature and not acceptable from the perspective of: a) the underdeveloped status of the classificatory concept of this entity, and b) its lack of adaptation to the present structure and coding options of ICD-11 neurocognitive disorders. On October 20/21, 2018, the authors of the VCI proposal posted an agreement7 with the above proposals and renounced the introduction of VCI in chapter 8. After being conveyed to responsible WHO bodies, the debate's outcome and resulting actions were officially endorsed at the WHO Family of International Classifications ICD-11 conference in Seoul. Since December 18, 2018, the proposed changes are implemented both in the frozen and the maintenance version of ICD-11 (https://icd.who.int/browse11/l-m/en).