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.

×
No Access

A reconsideration of the Kety and associates study of genetic factors in the transmission of schizophrenia

Published Online:https://doi.org/10.1176/ajp.133.10.1129

The author reviews a study by Kety and associates that reported a significantly greater prevalence of schizophrenic spectrum disorders among the biological relatives of schizophrenic adoptees than among those of nonschizophrenic adoptees. The principal statistical analysis of the Kety study used an incorrect sample size (306 rather than 66) and failed to weight each index and control case (family) equally. This violation of the independence assumption would allow a few families to disproportionately influence the outcome. The author argues that proper statistical analysis applied separately to available categories indicates that significant differences between the index and control groups occurred mainly in the half-sibling category; this result violates the principle that genetic effects increase with greater consanguinity. She concludes that Kety and associates' study raises more questions than it answers regarding the role of genetic factors in schizophrenia.

Access content

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