Dementia is an acquired clinical syndrome characterized by progressive, chronic deterioration in multiple cognitive domains—including memory, language, attention, executive function, visuospatial skills, and social cognition—of sufficient severity to impair a patient’s ability to function independently in daily life. It is distinguished from delirium (F05), which is acute, fluctuating, and characterized by impaired consciousness rather than by the chronic progressive course seen in dementia, and from mild cognitive impairment (MCI;F06.70-F06.71), in which cognitive decline has not yet significantly disrupted functional independence. The underlying mechanism varies by etiology: in Alzheimer’s disease (G30.x), amyloid-beta plaques and neurofibrillary tau tangles drive cortical neuron loss primarily in the hippocampus and association cortex; in vascular dementia (F01.xx), ischemic or hemorrhagic cerebrovascular lesions disrupt subcortical white matter circuits; and in Lewy body dementia (G31.83), alpha-synuclein inclusions impair dopaminergic and cholinergic neurotransmission. dementia is always pathological—never a normal consequence of aging—and ICD-10-CM classifies most forms under F01-F03, with mandatory dual coding required when a neurological etiology (G30.x, G31.x, G20.xx) underlies the dementia manifestation (F02.xx). Clinically coded subtypes include Alzheimer’s-type dementia (most common; G30.x + F02.xx), vascular dementia (F01.xx), Lewy body dementia (G31.83 + F02.xx), frontotemporal dementia (G31.09 + F02.xx), and Parkinson’s disease-related dementia (G20.xx + F02.xx). dementia is frequently confused with [[encephalopathy]] (G93.40), which denotes diffuse, often reversible brain dysfunction of metabolic, toxic, or hypoxic origin—the distinguishing feature being reversibility and acuity in encephalopathy versus irreversibility and chronicity in dementia.
The word entered English in the 1800s as dementia (noun), borrowed directly from Latin dementia, from dēmens (“out of one’s mind,” “senseless”), from de- (“away from”) + mens (“mind”) + -ia — literally “away from mind” or “a being out of one’s mind.” The root ment- (“mind”) connects dementia to the broader -ment- family: mental (ment- + -al → “pertaining to the mind”), mentality (capacity or character of mind), and the legal Latin phrase compos mentis (“in possession of one’s mind,” the standard for legal competency). The privative prefixde- is highly productive in medical Latin and appears in clinical terms including degeneration, decortication, denervation, debridement, and demyelination.
🔀 ALIASES / ALTERNATE TERMS
Demented(adjective form; used clinically in phrases such as “demented patient,” “severely demented elder,” or “demented with behavioral disturbance”; modern documentation style favors “patient with dementia” over “demented patient”)
Major neurocognitive disorder(DSM-5 preferred diagnostic term; operationally synonymous with dementia; used in psychiatric documentation and coded under F01-F03 depending on etiology and severity)
Senility / Senile dementia(outdated lay and historical clinical terms; no longer used in diagnostic coding; if documented by a provider without further specification or etiology, the default code is F03.90)
Cortical dementia(describes dementias primarily affecting cortical gray matter — Alzheimer’s disease, frontotemporal dementia — where memory, language, and praxis are predominantly impaired)
Subcortical dementia(affects deep nuclei and white matter — vascular, Parkinson’s-related, Huntington’s disease — characterized by psychomotor slowing, gait disturbance, and executive dysfunction with relative memory sparing early on)
Lewy body dementia (LBD / DLB)|Dementia with Lewy bodies(neurodegenerative subtype defined by alpha-synuclein inclusions; hallmark triad of fluctuating cognition, recurrent visual hallucinations, and parkinsonism; dual-coded G31.83 + F02.xx)
Frontotemporal dementia (FTD)|Pick’s disease(preferentially affects frontal and temporal lobes; behavioral variant presents with personality change, disinhibition, and apathy; language variants include progressive nonfluent aphasia and semantic dementia; dual-coded G31.09 or G31.01 + F02.xx)
Vascular dementia(caused by cerebrovascular disease including multi-infarct state, strategic infarct, and white matter ischemia; stepwise or insidious progression; coded F01.xx with severity and behavioral disturbance specificity required)
Secondary dementia(dementia attributable to a separately coded neurological or systemic condition; always requires the etiology code sequenced first with F02.xx as the manifestation code per ICD-10-CM instructional notes)
Pseudodementia(cognitive impairment mimicking dementia but caused by severe depression or other psychiatric disorder; fully or partially reversible with treatment; coded under the psychiatric condition — not under dementia codes)
🔗 RELATED TERMS
Delirium — acute, fluctuating disturbance in attention and consciousness; coded F05; potentially reversible when the underlying cause is treated; distinguished from dementia by abrupt onset, fluctuating arousal, and inattention as core features rather than chronic progressive cognitive loss; patients with dementia carry markedly elevated risk for superimposed delirium during inpatient admissions
Mild cognitive impairment — acquired cognitive decline not meeting dementia criteria for functional impairment; coded F06.70 (unspecified) or F06.71 (mild); may represent a prodromal phase of Alzheimer’s or other dementias; by definition does not impair independent daily functioning
Encephalopathy — diffuse brain dysfunction of metabolic, toxic, hypoxic, or structural origin; coded G93.40 (unspecified) or G93.41 (metabolic); distinguished from dementia by potential reversibility and acute or subacute presentation; may coexist with underlying dementia during inpatient admissions
Vascular dementia — dementia caused by cerebrovascular disease; coded F01.xx; the sixth character distinguishes severity (unspecified, mild A, moderate B, severe C) and behavioral/psychiatric disturbance subtype
Lewy body dementia — second most common neurodegenerativedementia; dual-coded G31.83 + F02.xx; REM sleep behavior disorder is a core diagnostic feature and may predate cognitive decline by years
Frontotemporal dementia — coded G31.09 or G31.01 (Pick’s disease); behavioral variant is most common; earlier onset than Alzheimer’s (typically 45-65 years); tau or TDP-43 proteinopathy is the underlying pathological substrate
Amyloid — misfolded protein forming extracellular plaques in Alzheimer’s disease; primary target of amyloid PET imaging (CPT 78608) and emerging disease-modifying immunotherapies (lecanemab, donanemab)
Behavioral disturbance — agitation, aggression, wandering, disinhibition, or other non-cognitive neuropsychiatric symptoms complicating dementia; the presence, absence, and specific type of behavioral disturbance is a mandatory coding axis across the F01, F02, and F03 code families
Neuropsychological testing — standardized cognitive assessment battery used to confirm dementia diagnosis, characterize subtype, and quantify severity across domains; reported with CPT 96132-96133 (evaluation by QHP) and 96136-96137 (test administration and scoring)
Cholinesterase inhibitor — pharmacological class (donepezil, rivastigmine, galantamine) used in mild-to-moderate Alzheimer’s dementia to slow symptom progression via inhibition of acetylcholinesterase; also trialed in Lewy body dementia
Dementia in other diseases classified elsewhere, unspecified severity, without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety
Neuropsychological testing evaluation services, with or without medical record review and feedback to patient or family with written report; first hour
Neurobehavioral status examination (clinical assessment of thinking, reasoning, and judgment, including acquisition of relevant history); first hour of face-to-face time with patient
Psychological or neuropsychological test administration and scoring by physician or other qualified health care professional; each additional 30 minutes
MRI brain without contrast, followed by contrast material(s) and further sequences (used when neoplasm, inflammation, rapid-onset dementia, or atypical dementia etiology is suspected)
Brain imaging, tomographic (SPECT); used in Lewy body dementia and frontotemporal dementia differentiation via dopamine transporter or perfusion imaging
Brain imaging, PET; metabolic evaluation (FDG-PET for hypometabolism pattern in Alzheimer’s, FTD; amyloid PET for amyloid burden confirmation)
⚠️ Coding Note: Dementia codes in the F01, F02, and F03 families require specificity along two mandatory axes: (1) etiology and type — unspecified (F03.xx), vascular (F01.xx), or due to an identifiable neurological condition (F02.xx with the etiology code sequenced first per the “Code first underlying condition” instructional note); and (2) severity and behavioral or psychiatric disturbance subtype — unspecified severity, mild (A), moderate (B), or severe (C), further specified as without disturbance (x0), with agitation (x11), with other behavioral disturbance (x18), with psychotic disturbance (x2), with mood disturbance (x3), or with anxiety (x4). For Alzheimer’s disease, Lewy body dementia, frontotemporal dementia, and Parkinson’s disease-related dementia, the neurological etiology code always sequences first with F02.xx assigned as the secondary manifestation code — reversing this sequence is a coding error. Inpatient profee coders should initiate a physician query when the record documents only “dementia,” “memory loss,” “cognitive decline,” “confusion,” “sundowning,” “agitation,” or “wandering” without specifying etiology, severity, or behavioral disturbance type, as these documentation patterns commonly result in undercoding to F03.90 when a more specific code is supported. Dementia codes with behavioral disturbance (x11 and x18 subcodes) frequently carry MCC weight in MS-DRG grouping and should never be undercoded when agitation or other behavioral disturbance is actively managed during the admission — documentation of the specific type of disturbance (agitation, psychosis, mood, or anxiety) yields the most specific code and supports the highest appropriate DRG severity level.