mental illness

American  

noun

• mental illnesses
  plural

1. any of the various forms of psychosis or severe neurosis.

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mental illness British  

noun

1. any of various disorders in which a person's thoughts, emotions, or behaviour are so abnormal as to cause suffering to himself, herself, or other people

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mental illness Scientific  

/ mĕn′tl /

1. Any of various psychiatric disorders or diseases, usually characterized by impairment of thought, mood, or behavior.

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Other Word Forms

Noun Inflected Forms

• mental illnesses
  plural

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Etymology

Origin of mental illness

First recorded in 1960–65

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Example Sentences

See Examples For:

mental illness

What is not happening with mental health, though, is an increase in severe mental illness.

From BBC ● Oct. 9, 2026

Polls suggest the majority of Canadians support access, external to medically assisted death but that support falls it comes to patients with mental illness alone.

From BBC ● Oct. 7, 2026

Rock awkwardly tries to expand this into a story about mental illness.

From Los Angeles Times ● Oct. 7, 2026

Canada was first set to expand its assisted dying laws to people whose sole condition is mental illness in 2023, but it delayed doing so twice to allow for time to study its potential delivery.

From BBC ● Oct. 7, 2026

William shared a ward with up to twenty other men who were also battling mental illness.

From "The Woman All Spies Fear" by Amy Butler Greenfield

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Related Words

• insanity
• mental disorder

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