On psychosis in twins

Twins have always attracted attention and aroused interest, both because of their relative rarity, and equally because of their inherent characteristics. From the side of their external structure, they have been the subject of study for a very long time (for example, the Hungarian sisters Judith and Elena were described in sufficient detail and accurately at the beginning of the 13th century). The psychoses observed in twins attracted attention much later: the first case of such recorded in the literature refers to 1812 and belongs to Rüsh. Then, from time to time, descriptions of individual cases appeared, and the attention of the authors was directed to Ch. arr. on the similarity of the psychopathic picture in twins. Although these descriptions were in most cases somewhat accidental, nevertheless the accumulated material allowed Ball in 1884 in De la folie gemellaire to make an attempt to single out a special form of twin psychosis, which he called "Folie gemellaire". When constructing his form, he proceeded from the assumption of the identity of psychosis in both twins, therefore, the main features of Folie gemellaire, in his opinion, were: 1) the simultaneous manifestation of seizures, 2) parallelism in relation to delirium and other mental abnormalities, 3) self-origin delirium in each of the individuals affected by it (cited by Dеjеrіnе).