Which factor increases the odds of developing schizophrenia when combined with genetic risks, as described in the material?

Which factor increases the odds of developing schizophrenia when combined with genetic risks, as described in the material?

• A. Prenatal viral exposure
• B. Urban upbringing
• C. Cannabis use
• D. Childhood trauma

Answer: (A)

The main idea tested here is gene–environment interaction in schizophrenia. The risk of developing schizophrenia isn’t determined by genetics or environment alone; when you have a genetic predisposition, certain environmental factors can interact with that risk to greatly increase the odds. Prenatal viral exposure stands out because maternal infection during pregnancy can disrupt fetal brain development in ways that amplify an existing genetic vulnerability. This combination—genetic risk plus prenatal viral insult—has a strong, well-documented impact on later schizophrenia risk, more so than either factor alone. Urban upbringing, cannabis use, and childhood trauma are all associated with higher risk, but the material describes prenatal viral exposure as the factor that increases odds specifically when combined with genetic risks.

The main idea tested here is gene–environment interaction in schizophrenia. The risk of developing schizophrenia isn’t determined by genetics or environment alone; when you have a genetic predisposition, certain environmental factors can interact with that risk to greatly increase the odds.

Prenatal viral exposure stands out because maternal infection during pregnancy can disrupt fetal brain development in ways that amplify an existing genetic vulnerability. This combination—genetic risk plus prenatal viral insult—has a strong, well-documented impact on later schizophrenia risk, more so than either factor alone.

Urban upbringing, cannabis use, and childhood trauma are all associated with higher risk, but the material describes prenatal viral exposure as the factor that increases odds specifically when combined with genetic risks.