F05.1 ICD-10-CA code: Delirium superimposed on dementia

F05.1 is the ICD-10-CA code for “Delirium superimposed on dementia” in CIHI’s FY 2026–2027 release, in effect from Apr 1, 2026.

Official description

F05.1

Delirium superimposed on dementia

ICD-10-CA · Canada · Also written F051

Index terms

Entries in CIHI’s alphabetical index that lead to F05.1. Searching the index by the condition the note names is how coders reach this code.

  • Senile, senility, with, acute confusional state
  • Dementia (persisting), senile, with acute confusional state
  • State (of), confusional (psychogenic), acute or subacute, with senility or dementia
  • Delirium, delirious (acute or subacute) (not alcohol or drug induced), superimposed on dementia

Notes for F05.1

As CIHI prints them, with any note F05.1 takes from the headings above it.

Includes

Use additional code

Add a code for this detail when the note documents it.

Excludes

Conditions classified elsewhere.

Note

  • An etiologically nonspecific organic cerebral syndrome characterized by concurrent disturbances of consciousness and attention, perception, thinking, memory, psychomotor behaviour, emotion, and the sleep-wake schedule. The duration is variable and the degree of severity ranges from mild to very severe.From F05 Delirium, not induced by alcohol and other psychoactive substances
  • New coding direction for the DAD and NACRS When a diagnosis of delirium, documented by the physician/primary care provider, is classified to a code from category F05 Delirium, not induced by alcohol and other psychoactive substances, Assign the appropriate code for delirium per the alphabetical index, mandatory, regardless of significance (refer to examples 1, 3, 4 and 5), and Assign an additional code, mandatory, to identify any known underlying disease, regardless of significance, when the physician/primary care provider documents the underlying disease (that caused the delirium) (refer to example 4) When the physician/primary care provider documents delirium and dementia, Assign the appropriate code for delirium per the alphabetical index, mandatory, regardless of significance (refer to examples 1, 3, 4 and 5), and Assign a code for the type of dementia, mandatory, regardless of significance (refer to examples 3 and 4), and Assign an additional code, mandatory, to identify the underlying disease, regardless of significance, when the physician/primary care provider documents the underlying disease (that caused the delirium) (refer to example 4) General notes (apply to all above directive statements) “Delirium” must be documented as a diagnosis before a code is assigned. The signs and symptoms of delirium may include cognitive (confusion, disorientation, memory problems) or behavioural and emotional (changes in alertness or personality) or other (sensitivity to light or sound, rambling speech). Do not assign a code for delirium based on the signs and symptoms alone (refer to example 2). Diagnosis typing or problem definitions apply. When delirium or any documented underlying disease that caused the delirium does not meet the criteria for significance, apply diagnosis type (3)/OP to the code(s). Delirium superimposed on dementia (DSD) is associated with increased morbidity and mortality. The cause/effect relationship does not have to be documented to assign F05.1 Delirium superimposed on dementia (DSD). Documentation that both conditions are present is sufficient. F05.8 Other delirium is assigned per the alphabetical index. It includes delirium of mixed origin (one or more documented underlying diseases that caused the delirium and dementia) (refer to example 4). Mixed delirium (delirium that alternates between hyperactive and hypoactive symptoms) is not the same as delirium of mixed origin or multiple etiologies. A documented diagnosis of mixed delirium (hyperactive, hypoactive subtypes) without a documented underlying cause is classified to F05.9 Delirium, unspecified.From F05 Delirium, not induced by alcohol and other psychoactive substances
  • This block comprises a range of mental disorders grouped together on the basis of their having in common a demonstrable etiology in cerebral disease, brain injury, or other insult leading to cerebral dysfunction. The dysfunction may be primary, as in diseases, injuries, and insults that affect the brain directly and selectively; or secondary, as in systemic diseases and disorders that attack the brain only as one of the multiple organs or systems of the body that are involved.Dementia (F00-F03) is a syndrome due to disease of the brain, usually of a chronic or progressive nature, in which there is disturbance of multiple higher cortical functions, including memory, thinking, orientation, comprehension, calculation, learning capacity, language, and judgement. Consciousness is not clouded. The impairments of cognitive function are commonly accompanied, and occasionally preceded, by deterioration in emotional control, social behaviour, or motivation. This syndrome occurs in Alzheimer's disease, in cerebrovascular disease, and in other conditions primarily or secondarily affecting the brain.From F00-F09 Organic, including symptomatic, mental disorders

Where F05.1 sits

  1. 1ChapterChapter 5: Mental and behavioural disorders (F00-F99)
  2. 2Block F00-F09Organic, including symptomatic, mental disorders
  3. 3Category F05Delirium, not induced by alcohol and other psychoactive substances
  4. 4Valid code F05.1Delirium superimposed on dementia

Source and release

Data release
ICD-10-CA · FY 2026–2027
Effective date
Apr 1, 2026
Publisher
CIHI

This page is built from the ICD-10-CA catalog that Vero Codes reads when it suggests codes: Canadian Institute for Health Information’s FY 2026–2027 release, imported from the publisher’s file and checked against it. The description, notes and structured data come from the same record.

Frequently asked questions

What does ICD-10-CA code F05.1 mean?

F05.1 is the ICD-10-CA code for “Delirium superimposed on dementia” in CIHI’s ICD-10-CA FY 2026–2027 release.

Where is F05.1 in ICD-10-CA?

F05.1 sits under F05 Delirium, not induced by alcohol and other psychoactive substances, within F00-F09 Organic, including symptomatic, mental disorders, within Chapter 5: Mental and behavioural disorders (F00-F99).

What coding notes apply to F05.1?

ICD-10-CA lists Use additional code, Note, Includes, Excludes notes for F05.1, including those from the headings it sits under. They are listed on this page with where each one comes from.

Which ICD-10-CA release does this page use?

It uses CIHI’s FY 2026–2027 release, in effect from Apr 1, 2026 to Mar 31, 2027. It is a reference: confirm the code against the current list and the payer’s rules before you submit it.