What is the basis of the modern biologic hypothesis of schizophrenia?

• A. Dopamine
• B. Serotonin
• C. GABA
• D. Glutamate

Answer: (A)

The basis of the modern biologic view is that dopamine signaling abnormalities drive many of schizophrenia’s features. In particular, excess dopamine activity in the mesolimbic pathway is linked to positive symptoms such as delusions and hallucinations. This is supported by the fact that drugs blocking D2 dopamine receptors reliably reduce these symptoms, and that substances that boost dopamine can provoke psychosis. Imaging and pharmacologic data show a clear link between dopamine transmission and psychotic experiences, reinforcing why dopamine blockade is a central therapeutic mechanism.

It's important to recognize that other neurotransmitter systems—glutamate, GABA, and serotonin—also play roles and interact with dopamine, helping explain negative symptoms, cognitive deficits, and the variability in treatment response. But the foundational concept remains: dysregulated dopamine signaling is the core anchor of the modern biologic explanation for schizophrenia.