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

Etymology

Origin of mental illness

First recorded in 1960–65

Example Sentences

See Examples For:

mental illness

Don’t miss: ‘I currently give him $1,000 a month’: My grandson has severe mental illness.

From MarketWatch ● Sep. 14, 2026

Linton had struggled with bipolar disorder for years before the crash and was twice hospitalized due to issues related to her mental illness.

From Los Angeles Times ● Sep. 8, 2026

Members of the Goldman family had been fighting over money since the 1980s, lobbing accusations of cheating and fraud and mental illness.

From The Wall Street Journal ● Sep. 5, 2026

Leo abandoned the family and moved to California when Steinem was 10 years old, leaving her to care for Ruth who had long suffered with mental illness and had terrifying hallucinations.

From BBC ● Sep. 3, 2026

I read more and see that he was described as "troubled" and suffering from "mental illness."

From "The Sky at Our Feet" by Nadia Hashimi

Related Words

• insanity
• mental disorder