**Question:** A patient of depression is getting chlorpromazine, but his auditory hallucinations are not controlled. The next drug is given

A. Haloperidol
B. Risperidone
C. Quetiapine
D. Fluoxetine

**Core Concept:** Antipsychotics

**Why the Correct Answer is Right:**

Chlorpromazine is a typical antipsychotic drug that primarily acts as a dopamine antagonist, particularly blocking D2 receptors in the brain. Although it is effective in treating psychosis associated with schizophrenia, its efficacy in treating auditory hallucinations in depression may be limited due to its broader spectrum of actions that also include blocking serotonin receptors (5-HT2A). When the patient's auditory hallucinations are not controlled despite chlorpromazine use, we need to consider a drug with more specific dopaminergic antagonism.

**Why Each Wrong Option is Incorrect:**

A. Haloperidol (Haldol): A typical antipsychotic drug with higher affinity for D2 receptors than chlorpromazine. It is more effective in controlling auditory hallucinations in depression due to its higher selectivity for D2 receptors.

B. Risperidone (Risperdal): Another typical antipsychotic drug with high affinity for D2 receptors, similar to Haloperidol. It is more effective in controlling auditory hallucinations in depression due to its higher selectivity for D2 receptors.

C. Quetiapine (Seroquel): An atypical antipsychotic drug with a broader spectrum of actions, including 5-HT2A antagonism. It is less selective for D2 receptors than Haloperidol and Risperidone, resulting in less effective treatment for auditory hallucinations in depression.

D. Fluoxetine (Prozac): A selective serotonin reuptake inhibitor (SSRI) primarily targeting serotonin reuptake. Although it is effective in treating depression, it does not address the auditory hallucinations caused by dopaminergic hyperactivity.

**Clinical Pearl:** Selective dopamine antagonists like Haloperidol, Risperidone, and Risperidone are preferred for treating auditory hallucinations in depression as they have higher selectivity for D2 receptors compared to atypical antipsychotics like Quetiapine and Fluoxetine.

**Correct Answer:** Haloperidol (Haldol)

**Why:**

Haloperidol is a typical antipsychotic drug with high affinity for D2 receptors, which makes it more selective for D2 receptors than chlorpromazine and other atypical antipsychotics like quetiapine and fluoxetine. By targeting D2 receptors, Haloperidol is more effective in controlling auditory hallucinations caused by dopaminergic hyperactivity.

**Why Each Wrong Option is Invalid:**

1. Quetiapine (Seroquel) is an atypical antipsychotic drug with broader spectrum of actions, including 5-HT2A antagonism. Due to its broader actions