[Insanity of two. Clinical symptomatology and psychosocial factors of induced paranoid disorder].

AIM The primary aim of the research was to identify factors which are associated with the appearance of induced psychotic disorders. The psychological and social factors and cultural diversity of symptoms and course of folie à deux were taken into account. METHOD The author's review of literature on the topic of folie à deux. RESULTS Folie à deux was first described in the 19th century. Since then the concept has been elaborated, and several psychosocial and demographical factors which favour a development of folie à deux have been described. Those involved are often isolated from society and have a close emotional relationship. Folie à deux has occurred most often in relationships within a nuclear family, especially between sisters, spouses, mother and child. The primary partner has been noted as being older, more intelligent and better educated. In most cases, the person in whom the delusions are induced is dependent on or submissive to the person with the psychotic disorder. CONCLUSION Psychological, social and demographical factors play an important role in emergence of shared paranoid disorders.