Which of the following drug effects closely mimics “Schizophrenia”.
**Core Concept**
Phencyclidine (PCP) and ketamine are known to induce a psychosis-like state in humans, closely mimicking the symptoms of schizophrenia. This is due to their action as NMDA receptor antagonists, which disrupts normal glutamatergic neurotransmission and leads to excitotoxicity.
**Why the Correct Answer is Right**
The mechanism of action of PCP and ketamine involves the blockade of NMDA receptors, specifically the NR1/NR2A subunits. This leads to an increase in dopamine release, particularly in the mesolimbic pathway, resulting in symptoms such as hallucinations, delusions, and disorganized thinking. The pathophysiology of schizophrenia is thought to involve similar disruptions in glutamatergic and dopaminergic neurotransmission.
**Why Each Wrong Option is Incorrect**
* **Option A:** Haloperidol is a typical antipsychotic that acts as a dopamine D2 receptor antagonist, which is actually used to treat schizophrenia symptoms.
* **Option B:** Amphetamine is a stimulant that increases dopamine release, but its effects are more related to addiction and anxiety than psychosis.
* **Option C:** Diazepam is a benzodiazepine that enhances GABAergic neurotransmission, which is not related to the pathophysiology of schizophrenia.
**Clinical Pearl / High-Yield Fact**
PCP and ketamine-induced psychosis can be a useful model for studying the pathophysiology of schizophrenia, and has led to the development of novel therapeutic strategies targeting the glutamatergic system.
**Correct Answer:** B. Ketamine.