

If the parties are admitted to hospital separately, then the delusions in the person with the induced beliefs usually resolve without the need of medication.

This case study is taken from Enoch and Ball’s ‘Uncommon Psychiatric Syndromes’ (2001, p181): Margaret and her husband Michael, both aged 34 years, were discovered to be suffering from folie à deux when they were both found to be sharing similar persecutory delusions. The disorder was first conceptualized in 19th century French psychiatry. Recent psychiatric classifications refer to the syndrome as shared psychotic disorder (DSM-IV) (297.3) and induced delusional disorder (F.24) in the ICD-10, although the research literature largely uses the original name.

The same syndrome shared by more than two people may be called folie à trois, folie à quatre, folie en famille or even folie à plusieurs (“madness of many”). Folie à deux (or shared psychosis) is a psychiatric syndrome in which symptoms of a delusional belief are transmitted from one individual to another.
