Folie à quatre.

A case of folie à quatre is described affecting a proband and his wife, sister and brother. The three family members retained their symtoms of paranoid schizophrenia. The wife was not mentally ill and her delusions disappeared in time (folie imposée). Coincidentally, there were several cases of Huntington's chorea amongst her relatives. Different categories of folie à deux are demonstrated in the various family members and relationships.