THIS PAPER reports a case of folie à famille in Taiwan, in which a man transmitted his persecutory delusion to his sister and then to his sister's husband and later to five of their children. The man and his brother-in-law were hospitalized in the Department of Neuro-Psychiatry, National Taiwan University Hospital at Taipei and all the members of this family were studied by me (Figure). In addition to the description of the onset and vicissitudes of the paranoid delusion occurring in each member of this family, an attempt will be made to understand the dynamics of this rare occurrence in terms of personality, family, and environment.
Folie à deux, the psychosis of association, is characterized by "the transference of delusional ideas and/or abnormal behavior from one person to one or more individuals who have been in close association with the primary affected patient."1 For