psychosis

American  

[sahy-koh-sis] / saɪˈkoʊ sɪs /

noun

Psychiatry.

psychoses plural

1. a mental disorder characterized by symptoms, such as delusions or hallucinations, that indicate impaired contact with reality.

2. any severe form of mental disorder, as schizophrenia or paranoia.

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psychosis British  

/ saɪˈkəʊsɪs /

noun

1. any form of severe mental disorder in which the individual's contact with reality becomes highly distorted Compare neurosis

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psychosis Scientific  

/ sī-kō′sĭs /

psychoses plural

1. A mental state caused by psychiatric or organic illness, characterized by a loss of contact with reality and an inability to think rationally. A psychotic person often behaves inappropriately and is incapable of normal social functioning.

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psychosis Cultural  

1. A severe mental disorder, more serious than neurosis, characterized by disorganized thought processes, disorientation in time and space, hallucinations, and delusions. Paranoia, manic depression, megalomania, and schizophrenia are all psychoses. One who suffers from psychosis is psychotic.

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Etymology

Origin of psychosis

First recorded in 1840–50, psychosis is from the Late Greek word psȳ́chōsis animation, principle of life. See psych-, -osis

Compare meaning

How does psychosis compare to similar and commonly confused words? Explore the most common comparisons:

• neurosis vs. psychosis

Explanation

If your Uncle Marvin starts talking to his furniture and sewing his own clothes out of newspapers, he may be suffering from psychosis, which is a serious psychiatric illness in which a person loses touch with reality. The Greek psykhe, or "mind" combines with the Latin suffix -osis, "abnormal condition," to form the word psychosis. An "abnormal condition of the mind" sounds like it could describe a lot of mental conditions, and in fact psychosis is a broad term that covers many different disorders. The symptom that those who suffer from psychosis have in common is that they don't experience reality in the same way that most people do; they may hallucinate, or see and hear things that aren't really there.

Example Sentences

After tests in a provincial laboratory failed to pinpoint Ebola as the source, the disease and accompanying psychosis were both allowed to spread in Mongbwalu.

From Barron's • May 24, 2026

Mental-health professionals are recognizing chatbot delusions and psychosis as a phenomenon meriting further study.

From The Wall Street Journal • May 23, 2026

Last June, a BBC Spotlight investigation heard hard hitting testimonies from women who'd suffered severe post-partum psychosis and post-natal depression and who'd been cared for without their babies with them.

From BBC • Apr. 30, 2026

For years, researchers have proposed that psychosis may result from a reduced ability to update beliefs when new information becomes available.

From Science Daily • Apr. 3, 2026

The crowding, poor nutrition, and lack of hygiene made disease rampant; from typhus to scarlet fever, from malnutrition to psychosis, illness of some kind struck nearly every family.

From "The Boy on the Wooden Box" by Leon Leyson

Related Words

• absurdity
• alienation
• craziness
• folly
• frenzy
• hysteria
• irresponsibility
• lunacy
• madness
• mental disorder