Question

Which of the following are biological factors in the development of schizophrenia?
Correct Answer(s)
Schizophrenia is obvious even in young children.
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For both identical and fraternal twins, if one develops schizophrenia, then the likelihood that the other will develop it too is almost 50 percent.
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People with schizophrenia have larger brain ventricles and less brain tissue in the frontal and temporal lobes.
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A child whose parents both have schizophrenia has a nearly 50 percent chance of developing the disorder.
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Incorrect Answer(s)

Answer 1

Biological factors (correct):
- People with schizophrenia have larger brain ventricles and less brain tissue in the frontal and temporal lobes. (Structural brain differences are linked to the disorder.)
- A child whose parents both have schizophrenia has a nearly 50 percent chance of developing the disorder. (Having two affected parents greatly increases genetic risk.)

Incorrect / not a biological generalization:
- Schizophrenia is obvious even in young children. (Onset is usually in late adolescence or early adulthood; childhood-onset is rare.)
- For both identical and fraternal twins, if one develops schizophrenia, then the likelihood that the other will develop it too is almost 50 percent. (Identical twins show a much higher concordance than fraternal twins—MZ concordance is around 40–50%, DZ much lower—so the “both types ~50%” statement is false.)