[Determination of similarity and dissimilarity of endogenous psychoses in monozygotic twins based on a differential diagnosis].

The frequently published opinion that endogenous psychoses in monozygotic twins often show a marked lack of similarity could not be confirmed by the results of studies performed by the author and his associates. In general, differenting diagnosis allows the particular syndrome, on which the establishment of the respective diagnosis is based, to be nearly always observed in either partner. On the other hand, changes of mood, which are accessory symptoms, often show a different picture which may perhaps be regarded as being due to the fact that monozygotic twins often differ in their respective temperaments. The course and severity of the disease also usually show considerable differences which may in part be due to additional affections.