Fuck me gently with a chainsaw

Folie à deux (English pronunciation: /fɒˈli ə ˈduː/, from the French for “a madness shared by two”) (or shared psychosis) is a^[1]psychiatric syndrome in which symptoms of a delusional belief are transmitted from one individual to another. 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”). 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 disorder was first conceptualized in 19th century French psychiatry.