dementia

American  

[dih-men-shuh, -shee-uh] / dɪˈmɛn ʃə, -ʃi ə /

noun

• dementias
  plural

1. a condition characterized by progressive, persistent, severe impairment of intellectual capacity, including memory loss, confusion, and emotional instability, resulting from the loss of or damage to neurons in the brain.

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dementia British  

/ dɪˈmɛnʃə, -ʃɪə /

noun

1. a state of serious emotional and mental deterioration, of organic or functional origin

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dementia Scientific  

/ dĭ-mĕn′shə /

1. Deterioration of intellectual faculties, such as memory, concentration, and judgment, sometimes accompanied by emotional disturbance and personality changes. Dementia is caused by organic damage to the brain (as in Alzheimer's disease), head trauma, metabolic disorders, or the presence of a tumor.

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Other Word Forms

Derived Forms

• demential
  adjective

Inflected Forms

Nouns

• dementias
  plural

Etymology

Origin of dementia

First recorded in 1800–10; from Latin dēmentia “madness,” equivalent to dēment- “out of one's mind” ( see dement) + -ia noun suffix

Compare meaning

How does dementia compare to similar and commonly confused words? Explore the most common comparisons:

• dementia vs. senility

Explanation

If your grandfather suffers from dementia, he has a brain disorder that's causing him to gradually lose his memory and become disoriented and confused. Although dementia is most common in elderly people, it's not a normal part of growing older but a syndrome caused by brain disease or injury. Dementia gets its name from the Latin words de, or "without," and mens, or "mind," which join together to mean "madness," although in English, dementia is not the same thing as madness. One example of an illness that causes dementia is Alzheimer's disease.

Example Sentences

See Examples For:

dementia dementias

Meanwhile dementia deaths have tripled and anxiety- and depression-related health loss has risen sharply since the Covid-19 pandemic.

From Barron's ● Oct. 2, 2026

Nine siblings face a collective struggle against frontotemporal dementia, which strikes in middle age and radically changes lives and personalities.

From The Wall Street Journal ● Sep. 30, 2026

A growing body of research across the world is finding that sports with lots of head contact can cause brain damage, brain disease, dementia and related conditions such as Parkinson’s.

From MarketWatch ● Sep. 30, 2026

Psychiatric disorders were associated with elevated PAD in the frontal and temporal lobes, while dementia was linked to higher PAD in the frontal and occipital cortex.

From Science Daily ● Sep. 29, 2026

Black men, women, and children suffering with everything from dementia and tuberculosis to “nervousness,” “lack of self-confidence,” and epilepsy were packed into every conceivable space, including windowless basement rooms and barred-in porches.

From "The Immortal Life of Henrietta Lacks" by Rebecca Skloot

While most people associate dementia with the memory loss and cognitive decline of Alzheimer’s disease, other dementias like FTD strike even deeper at the heart of human identity.

From The Wall Street Journal ● Sep. 18, 2026

While most Americans believe lifestyle behaviors are very important for brain health, fewer than half strongly link these behaviors with reducing the risk of Alzheimer’s or other dementias, the group said.

From MarketWatch ● Jul. 15, 2026

In turn, targeted therapies will either prevent Alzheimer’s in the first place or convert it and other progressive dementias into chronically manageable or even curable conditions.

From The Wall Street Journal ● Jun. 20, 2026

It could also help identify people at higher risk of developing Alzheimer's disease and related dementias, even before any symptoms appear.

From Science Daily ● Apr. 22, 2026

In benign stupor purely mental stimuli may change the whole clinical picture abruptly and with this produce a change in the intellectual functioning such as we never see in organic dementias or clouded states.

From Benign Stupors A Study of a New Manic-Depressive Reaction Type by John T. (John Thompson) MacCurdy

Related Words

• brain damage
• mental disorder