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

This recounts the tragedy of a young man, Richard “Beebo” Russell, who in the throes of mental illness stole a plane and managed to take off into the Pacific Northwest.

From Los Angeles Times • Apr. 13, 2026

But Potter, who struggled with unchecked mental illness, depicted himself as an antihero outsider with a spiritual connection to the ravens of Yosemite, and could also be juvenile, selfish and oblivious.

From Los Angeles Times • Apr. 13, 2026

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

The legislation also garnered support from Mara Grunau, chief executive of the Canadian Mental Health Association's Alberta division, who said in a statement that "Recovery from mental illness and suicidality is possible, expected even".

From BBC • Mar. 18, 2026

Moni is not the only member of my father’s family with mental illness.

From "The Gene" by Siddhartha Mukherjee

Related Words

• insanity
• mental disorder