What conclusion did Gottesman and Shields draw from their study on twins?

• A. Schizophrenia can be entirely attributed to environmental factors
• B. Genetic factors have no relevance in developing schizophrenia
• C. Genetics play a role but are not solely responsible for schizophrenia
• D. All twin studies confirm genetics as the sole cause of schizophrenia

Answer: (C)

Gottesman and Shields conducted significant research on the genetic basis of schizophrenia, particularly through studying twins, which is an effective method for understanding the heritability of disorders. Their findings indicated that there is a higher concordance rate for schizophrenia in identical twins compared to fraternal twins, suggesting that genetic factors do contribute to the likelihood of developing the disorder. However, the study also showed that the concordance rate for identical twins is not 100%, meaning that not all twins share the condition even when they have the same genetic makeup.

This evidence supports the conclusion that while genetics play a crucial role in the development of schizophrenia, they are not the sole influence. Environmental factors, individual experiences, and potentially other non-genetic factors also contribute to the onset of the disorder. Therefore, the conclusion drawn from Gottesman and Shields' research emphasizes the complex interplay between genetic predispositions and environmental influences, leading to a nuanced understanding of schizophrenia's etiology.