Das Zwillingsproblem in der Psychiatrie

Abstract

SUMMARYThe prevalence of psychological tendencies in psychiatry and the scarceness of material in our small country have resulted in a certain neglect of the problem of twin studies (as part of the theory of constitution and genetics). Uni-ovular twins - meaning identical in their heredity, monozygotes - enable us to reach important conclusions regarding the influence of constitution on, and the hereditary character of psychiatric diseases. Apart from observations at birth, uni-ovularity is proved by the method of similarities in physical and psychological Traits, esp. finger-prints, blood groups, and handwritings; recently another proof has been found in the electro-encephalogramm (EEG) which is identical in uni-ovulars. Bi-ovular or non-identical twins (dizygotes) have every mark of siblings, e.g. the statistical percentage concerning the hereditary character of certain illness, which percentage is much smaller than with uni-ovular. The cases of five pars of identical twins are presently recorded: two pairs in detailed observation by the writer, three pairs which have been referred to me by the kindness of several institutions in this country. (It is by chance only that all these pairs are female). Of these five observations, four concordant uni-ovular twins belong to the schizophrenic form, one to the maniac-depressive.The history and literature regarding this trend of studies are referred to at some length, esp. the findings on criminal twins (Johannes Lange et al.) and the exhaustive material of F. J. Kallmann, New York, which latter did observe 953 pairs of schizophrenics, 75 pairs of maniac-depressives, 96 involution psychoses, etc. These studies and those by other authors show a concordance - meaning appearance of the same illness in both twins -of nearly 100% in maniac-depressives, and of up to 86% in schizophrenics. The limited discordance in schizophrenia is dealt with and explained by factors other than environmental - or (as some hold) even psychological influences on the genesis of schizophrenia. The « mother-child complex », meaning the influence of earliest childhood, is unacceptable as a factor in the origin of child schizophrenia.Therefore, observation of twins provides important conclusions on the constitutional or hereditary character of serious psychoses, as well as on criminality, suicide, homo-sexuality, involution psychosis, epilepsy, mongolism, mental debility, and many other problems of psychiatry and the important problem of influences by « nature and nurture », or constitution and environment, on psychic illness. All these make it possible to revise, in the sense of genetic constitution, several opinions held in psychotherapy, psycho-analysis, and psycho-somatics.