mental illness

American  

noun

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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Etymology

Origin of mental illness

First recorded in 1960–65

Example Sentences

Later, he hints at a troubled childhood; he says his father died but offers no stories about this, and mentions in passing mental illness, without saying whose.

From The Wall Street Journal • Mar. 19, 2026

Canada is also due to expand access next year to people whose only medical condition is mental illness, though that has twice been delayed.

From BBC • Mar. 18, 2026

A psychiatrist and an attorney in San Diego say an existing statute could address severe mental illness and addiction.

From Los Angeles Times • Feb. 28, 2026

Claire Brosseau rails against the idea that people with mental illness are incapable of making informed decisions.

From Barron's • Feb. 25, 2026

President Reagan's attacker, like Charles Guiteau, had a history of mental illness.

From "Ambushed!" by Gail Jarrow

Related Words

• insanity
• mental disorder