What was the focus of the Gottesman and Shields (1966) study?

The Gottesman and Shields study conducted in 1966 primarily investigated the genetic factors related to schizophrenia. This research is significant because it explored the heritability of schizophrenia by comparing the prevalence of the disorder among identical twins to that of fraternal twins. Since identical twins share nearly 100% of their genes while fraternal twins share about 50%, any significant difference in the rates of schizophrenia between these groups can suggest a genetic component to the disorder. The findings indicated that if one identical twin had schizophrenia, there was a higher probability of the other twin also being diagnosed compared to fraternal twins, which supports the idea that genetic factors play a crucial role in the development of this mental illness. This study contributed to our understanding of the biological and genetic underpinnings of schizophrenia, distinguishing it from environmental influences that might affect other aspects of psychological health.