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

Mr. Garson, a professor of philosophy at the City University of New York, has written previously on mental illness, and the opening pages tell us why the topic captivated him.

From The Wall Street Journal ● Jul. 28, 2026

"Not only that, evidence has been accumulating that it also raises the risk of cardiovascular diseases, diabetes and mental illness," says Kang Mo-yeol, professor of occupational medicine at the Catholic University of Korea.

From BBC ● Jul. 24, 2026

"We already knew psilocybin could be helpful for treating mental illness," Carhart-Harris said.

From Science Daily ● Jul. 22, 2026

California established mental health diversion in 2018 to prioritize treatment over punishment for eligible defendants whose mental illness contributed to their alleged offenses.

From Los Angeles Times ● Jul. 8, 2026

I couldn't understand why his trial records made no reference to mental illness, but after the George Daniel case, nothing surprised me.

From "Just Mercy" by Bryan Stevenson

Related Words

• insanity
• mental disorder