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

Even the graduates have challenges ahead, because generally speaking, although severe mental illness can be managed, it doesn’t go away.

From Los Angeles Times ● Jul. 29, 2026

But he soon became disillusioned with the psychodynamic account of mental illness advanced by Freudians and looked instead to the brain’s chemistry for answers.

From The Wall Street Journal ● Jul. 28, 2026

His mother and lawyers have been quoted as saying that he suffered from mental illness and injury, possibly from his time as an athlete.

From BBC ● Jul. 27, 2026

Truelove’s mental illness, his half-sister said, made it difficult for him to perform basic tasks, such as getting a job, paying bills or staying housed.

From Los Angeles Times ● Jul. 24, 2026

While my family’s history of mental illness was cutting through my consciousness like a red line, my scientific work as a cancer biologist was also converging on the normalcy and abnormalcy of genes.

From "The Gene" by Siddhartha Mukherjee

Related Words

• insanity
• mental disorder