folie à deux

Meanings

1. 1nounsingularmedical

   A mental disorder in which two people who are close to each other share the same delusion or false belief.

   Grammar: Used as a singular noun: a folie à deux is rare.

   Patterns

   • a folie à deux between two people

   The psychiatrist diagnosed a folie à deux between the two sisters.

   In a folie à deux, one person usually holds the delusion first and the other adopts it.

   Doctors separated the pair to see whether the folie à deux would fade.

2. 2nounsingularfigurativehumorous

   A foolish or mistaken idea shared by two people who encourage one another in it.

   Grammar: Used loosely and figuratively, often with a humorous tone.

   Their plan to row across the Atlantic was a folie à deux.

   The business partners suffered a kind of folie à deux about the product's value.

   Critics called the film a folie à deux between the writer and the director.

Common combinations

suffer from a folie à deux

The couple seemed to suffer from a folie à deux about the neighbours.

a case of folie à deux

The doctor described it as a case of folie à deux.

folie à deux between

There was a folie à deux between mother and son.

diagnose folie à deux

Few psychiatrists ever diagnose folie à deux.

Synonyms and how they differ

shared psychosis

Shared psychosis is the plain-English clinical name for the same condition, while folie à deux is the older French term.

groupthink

Groupthink describes a whole group conforming without critical thought, not specifically two people sharing a delusion.

mass hysteria

Mass hysteria involves a large crowd, whereas folie à deux is limited to two people.

Word family

folie noun

French for madness or folly

folly noun

foolishness or a foolish act

delusion noun

a false belief held despite evidence

Commonly confused: folie à deux or ménage à trois?

Practice

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