Folie à six: a case report on induced psychotic disorder.

A case of folie à six is described in which the persecutory delusions of the central figure spread to her husband and their 2 sons, and even to her sister-in-law and a nephew. The main factor in the development of this shared paranoid disorder seems to have been the dominant personality of the inducer. In contrast to reports in the literature, there was no family history of such disorders and there were no adverse social or environmental circumstances.