Which medication is used chiefly to block D2 receptors in the treatment of schizophrenia?

The medication that is chiefly used to block D2 receptors in the treatment of schizophrenia is chlorpromazine. Chlorpromazine is an older antipsychotic medication belonging to the class of typical antipsychotics, which primarily exert their effects through blockade of dopamine D2 receptors in the brain. By antagonizing these receptors, chlorpromazine helps alleviate positive symptoms of schizophrenia, such as hallucinations and delusions.

In contrast, the other medications mentioned have different profiles. Risperidone and olanzapine are both atypical antipsychotics that also affect serotonin receptors in addition to dopamine receptors. Clozapine, while very effective for treatment-resistant schizophrenia, has a unique mechanism involving lesser D2 blockade and greater affinity for various serotonin receptors. Due to their broader receptor-targeting profiles, atypical antipsychotics are often favored in modern treatment paradigms, but chlorpromazine remains a classic example of a D2 receptor blocker specifically in the context of schizophrenia management.