Identical Twins but Not Identical Brains David and Steven Elmore are identical twins, but they differ in one important respect—Steven (right) has schizophrenia. Behind each is a CT scan, which reveals that Steven’s brain is slightly smaller, with less area devoted to the cortex at the top of the brain. Steven also has larger fluid-filled ventricles, which are circled in red on his brain scan. As researcher Daniel Weinberger (1995) commented, “The part of the cortex that Steven is missing serves as perhaps the most evolved part of the human brain. It performs complicated tasks such as thinking organized thoughts. This might help explain why paranoid delusions and hallucinations are characteristic of schizophrenia.”

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