In plain English
A complete reference of ICD-11 codes for neurocognitive disorders. Each code is listed with its plain-English name and a brief description. Used by UK memory clinics, including The Dementia Service.
The Neurocognitive Disorders block
Acute and mild conditions
- 6D70 Delirium
- 6D70.0 Delirium due to disease classified elsewhere
- 6D70.1 Delirium due to psychoactive substances including medications
- 6D70.2 Delirium due to multiple etiological factors
- 6D70.Y Other specified Delirium
- 6D70.Z Delirium, unspecified or unknown cause
- 6D71 Mild Neurocognitive Disorder (commonly called Mild Cognitive Impairment, MCI)
- 6D72 Amnestic Disorder
- 6D72.0 Amnestic Disorder due to diseases classified elsewhere
- 6D72.1 Amnestic Disorder due to psychoactive substances including medications
Dementia (block)
6D80 Dementia due to Alzheimer's Disease
- 6D80.0 Dementia due to Alzheimer's Disease with Early Onset (before age 65)
- 6D80.1 Dementia due to Alzheimer's Disease with Late Onset (from age 65)
- 6D80.2 Alzheimer's Disease Dementia, Mixed Type, with Cerebrovascular Disease
- 6D80.3 Alzheimer's Disease Dementia, Mixed Type, with other non-vascular aetiologies
- 6D80.Y Other specified Dementia due to Alzheimer's Disease
- 6D80.Z Dementia due to Alzheimer's Disease, onset unknown or unspecified
6D81 Dementia due to Cerebrovascular Disease (Vascular Dementia)
Includes post-stroke Vascular Dementia, subcortical Vascular Dementia, multi-infarct dementia, Binswanger Disease.
6D82 Dementia due to Lewy Body Disease (Dementia with Lewy Bodies)
6D83 Frontotemporal Dementia
Includes Behavioural Variant FTD, Non-fluent Variant PPA, semantic variant PPA, Logopenic Variant PPA, and FTD with motor variants (PSP, CBS, MND).
6D84 Dementia due to Psychoactive Substances including Medications
- 6D84.0 Dementia due to use of alcohol
- 6D84.1 Dementia due to use of sedatives, hypnotics or anxiolytics
- 6D84.2 Dementia due to use of volatile inhalants
- 6D84.Y Dementia due to other specified psychoactive substance
6D85 Dementia due to diseases classified elsewhere
- 6D85.0 Dementia due to Parkinson's Disease
- 6D85.1 Dementia due to Huntington's Disease
- 6D85.2 Dementia due to exposure to heavy metals or other toxins
- 6D85.3 Dementia due to human immunodeficiency virus
- 6D85.4 Dementia due to multiple sclerosis
- 6D85.5 Dementia due to prion disease
- 6D85.6 Dementia due to Normal Pressure Hydrocephalus
- 6D85.7 Dementia due to injury to the head
- 6D85.8 Dementia due to pellagra
- 6D85.9 Dementia due to Down Syndrome
- 6D85.Y Dementia due to other specified disease
6D86 Behavioural or psychological disturbances in dementia (modifier codes)
- 6D86.0 Psychotic symptoms in dementia
- 6D86.1 Mood symptoms in dementia
- 6D86.2 Anxiety symptoms in dementia
- 6D86.3 Apathy in dementia
- 6D86.4 Agitation or aggression in dementia
- 6D86.5 Disinhibition in dementia
- 6D86.6 Wandering in dementia
How codes are used
A typical UK memory clinic letter combines a primary dementia code with severity (mild, moderate, severe) and any BPSD modifier codes. Example:
"ICD-11 6D80.2 Alzheimer's Disease Dementia, Mixed Type, with Cerebrovascular Disease, mild in degree, with 6D86.4 agitation."
This conveys: the type, the contributing vascular disease, the severity, and the principal behavioural feature in a single line.
Relationship to DSM-5
DSM-5 (the American Psychiatric Association classification) uses "Major Neurocognitive Disorder" instead of "dementia" and "Mild Neurocognitive Disorder" instead of "MCI". The clinical concepts overlap; the terminology differs. UK practice uses ICD-11.
Frequently asked questions
Why is there no general code for 'dementia'?
ICD-11 is specific by cause. The 'Dementia' grouping is a parent block; each diagnosis uses a specific subtype code.
What is the difference between 6D80 and 6D80.1?
6D80 is the parent code for any Alzheimer's Dementia. 6D80.1 is specifically late-onset (from age 65). 6D80.0 is early-onset (before 65). 6D80.2 is mixed with vascular.
When are the 6D86 codes used?
As modifier codes alongside a main dementia diagnosis, where a specific behavioural or psychological symptom is prominent.
What if no specific code fits?
Each subtype has a .Y (other specified) and .Z (unspecified) suffix for situations where the exact subtype is unclear or unusual.
Will codes change in future?
ICD revisions occur over years to decades. The current release is updated annually with minor changes. We update this page when codes change.
References
- World Health Organization. ICD-11 for Mortality and Morbidity Statistics. 2026 release. https://icd.who.int
- NICE NG97.
- American Psychiatric Association. DSM-5-TR (for comparison).
- International Classification of Diseases Working Group on Mental Disorders.