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

Fowlie also shared to his followers that Downer had no history of mental illness and had never “dropped off” before.

From Los Angeles Times • Apr. 30, 2026

President Donald Trump signs a directive to accelerate FDA review of psychedelic drugs for serious mental illness.

From Barron's • Apr. 20, 2026

Carruthers’ case is a perfect storm of capital punishment’s familiar failures: paid informants, information withheld from the jury, untested physical evidence, and the defendant’s mental illness.

From Slate • Apr. 20, 2026

Although the severity of Robert’s mental illness meant several lost years, he had a reprieve at one point for some months, and Hal hopes there may be fertile work left behind.

From The Wall Street Journal • Apr. 17, 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

Related Words

• insanity
• mental disorder