[Discordance analytic studies of monozygotic twins]

Discordance analyses of monozygotic twins make it possible to study the influence of neurotic pathogenic situations of early childhood upon later neurotic developments. The analysis offers the advantage of having a genetic double who was shaped by the same psychosocial macro influences and went through a sound development as a comparison for an examination of the course of psychogenic illnesses. However, two prerequisites are necessary: 1. the human genetic/anthropological or serological diagnosis in order to be able to definitely say whether the twins are monozygotic or not and 2. both twins must be alive. A strong discordance regarding markedness of characteristics or a varying degree of symptom manifestation as well as a longer period of observation are further conditions. With the example of four short casuistries of monozygotic twins the environmental variables which are decisive in the individual cases for the discordant development are described: A highly ambivalent early childhood relationship in contrast to a mostly balanced relationship is the foundation for a neurotic course in connection with pathological conspicuous behavior of the parents, sibling rivalry and differing attitudes of the parents regarding each of the twin siblings. As a result each twin identifies with a different parent, leads in development and dominance positions are also consequences. Later the course set in school and career, orientation regarding an intimate partner and the neurotically preformed personality structure, which is the basis for differing degrees of being able to cope successfully with threshold situations, become framing situations of discordant neurotic versus stable and sound development.