dementia

noun

de·​men·​tia di-ˈmen(t)-shə 

-shē-ə

1

: a usually progressive condition (such as Alzheimer's disease) marked by the development of multiple cognitive deficits (such as memory impairment, aphasia, and the inability to plan and initiate complex behavior)

… dementia is diagnosed only when both memory and another cognitive function are each affected severely enough to interfere with a person's ability to carry out routine daily activities.

—The Journal of the American Medical Association

2

: madness, insanity

a fanaticism bordering on dementia

demential

di-ˈmen(t)-shəl 

-shē-əl

adjective

Synonyms

• aberration
• derangement
• insanity
• lunacy
• madness
• mania
• rage [archaic]

Examples of dementia in a Sentence

This patient suffers from dementia.

a new study on age-related dementias

Recent Examples on the Web

Hulu 'Knox Goes Away' Michael Keaton directs and stars in the nifty crime thriller as a hitman diagnosed with Creutzfeldt–Jakob disease, a fast-acting and fatal form of dementia. —Brian Truitt, USA TODAY, 16 Aug. 2024

More than 900,000 people with Alzheimer’s or other types of dementia reside in nursing homes and assisted living centers. —Jordan Rau, CNN, 15 Aug. 2024

Russell died of Lewy body dementia and multiple system atrophy, his memoir co-author K.L. Doty confirmed to Rolling Stone. —Tomás Mier, Rolling Stone, 15 Aug. 2024

What This Means For You Patients interested in an Alzheimer’s blood test can ask their doctors about it now or ask for a referral to a dementia specialist who may be more likely to know about and even use the tests. —Fran Kritz, Verywell Health, 15 Aug. 2024

Word History

Etymology

borrowed from Latin dēmentia "derangement, insanity, folly," noun derivative of Latin dēment-, dēmens "out of one's mind, frenzied, insane," from dē- de- + -ment, -mens, adjective derivative of ment-, mens "power of reason, mental balance, mind" — more at mind entry 1

First Known Use

1806, in the meaning defined at sense 1

Phrases Containing dementia

• dementia praecox
• dementia pugilistica
• senile dementia

Kids Definition

dementia

noun

de·​men·​tia di-ˈmen-chə 

1

: a condition of the brain that is marked especially by a deterioration in the ability to think, reason, or remember

2

: a condition of deteriorating mental functioning

Medical Definition

dementia

noun

de·​men·​tia di-ˈmen-chə 

: a usually progressive condition (as Alzheimer's disease) marked by the development of multiple cognitive deficits (as memory impairment, aphasia, and inability to plan and initiate complex behavior)

demential

-chəl 

adjective