The development of a genetically predisposed disorder like schizophrenia may depend on what?

The development of a genetically predisposed disorder like schizophrenia may depend on what?

• A. Unrelated random factors
• B. Exposure to stress in the environment
• C. No environmental influence
• D. The blood type

Answer: (B)

Gene-environment interaction explains why a genetically predisposed disorder like schizophrenia may develop only when environmental stress is present. A genetic vulnerability increases risk, but exposure to stressful life events can activate or reveal that vulnerability, pushing a person past the threshold into illness. This diathesis-stress pattern is supported by twin studies showing high, but not perfect, concordance, indicating that non-genetic factors matter. Other options don’t fit because blood type isn’t linked to schizophrenia, and saying there’s no environmental influence ignores substantial evidence that stress can influence whether the predisposition leads to disorder. So, exposure to environmental stress is the key determinant in this scenario.

Gene-environment interaction explains why a genetically predisposed disorder like schizophrenia may develop only when environmental stress is present. A genetic vulnerability increases risk, but exposure to stressful life events can activate or reveal that vulnerability, pushing a person past the threshold into illness. This diathesis-stress pattern is supported by twin studies showing high, but not perfect, concordance, indicating that non-genetic factors matter. Other options don’t fit because blood type isn’t linked to schizophrenia, and saying there’s no environmental influence ignores substantial evidence that stress can influence whether the predisposition leads to disorder. So, exposure to environmental stress is the key determinant in this scenario.