When one identical twin has schizophrenia, the other develops it only about half of the time. What is the most likely explanation for this?
A) There is an environmental component involved in developing schizophrenia.
B) The twin who develops schizophrenia has a genetic mutation that the other twin does not have.
C) Identical twins share most genes, but they do not share the gene for schizophrenia.
D) Any genetic links to schizophrenia disappear once a person reaches early adulthood.

Question

Quizplus · Accepted Answer

The fact that only half of identical twins develop schizophrenia when the other twin has it suggests that environmental factors play a role in the development of the disorder. If schizophrenia were solely a result of genetics, then both twins would develop it.

When One Identical Twin Has Schizophrenia, the Other Develops It