The American Psychiatric Association (APA) has updated its Privacy Policy and Terms of Use, including with new information specifically addressed to individuals in the European Economic Area. As described in the Privacy Policy and Terms of Use, this website utilizes cookies, including for the purpose of offering an optimal online experience and services tailored to your preferences.

Please read the entire Privacy Policy and Terms of Use. By closing this message, browsing this website, continuing the navigation, or otherwise continuing to use the APA's websites, you confirm that you understand and accept the terms of the Privacy Policy and Terms of Use, including the utilization of cookies.

×
ArticleNo Access

MENTAL DISORDER IN ONE OF A PAIR OF IDENTICAL TWINS

Published Online:https://doi.org/10.1176/ajp.98.3.447

In this paper we have presented five cases of mental abnormality of various types in one identical twin. We have attempted to show that because of the identical heredity in monozygotic twins the study of cases of this type is of importance in showing the relative rôle played by inherited and environmental factors. In four cases we have been able to determine differences in environment which we feel are important in the etiology of their condition, knowing that by the continued mental health of the other twin we have ruled out the possibility that heredity in itself was the factor behind the illness. If we look upon studies of abnormality of one identical twin as a testing ground for our present day ideas on etiology, then our results are quite in keeping with these conceptions.

Access content

To read the fulltext, please use one of the options below to sign in or purchase access.