Okay, let me tackle this question. The patient has acute psychosis, which means a sudden onset of mental symptoms like delusions or hallucinations. The key points here are the patient's behavior upon seeing his wife. He mistakes her for a nurse who he believes gave him wrong medication and is now trying to harm him.

First, I need to think about the different types of psychosis. Acute psychosis can be caused by various factors like drug intoxication, mental illness, or medical conditions. The scenario here seems to involve paranoid delusions. The patient has a persecutory belief that someone is out to harm him, specifically the nurse in disguise.

The correct diagnosis might be delusional disorder, but wait, delusional disorder is usually chronic. Wait, no, acute psychosis can present with delusions. Alternatively, could it be schizophrenia? But the question mentions acute onset, which is more aligned with something like brief psychotic disorder. However, the presence of a specific, fixed delusion about being harmed by someone in disguise might point to a specific type.

Wait, Capgras syndrome. Capgras is when a person believes that someone close to them has been replaced by an imposter. The patient here thinks his wife is a nurse, which fits Capgras. But Capgras is usually associated with delusional misidentification syndromes. However, the question also mentions the patient has acute psychosis. So maybe the correct answer is Capgras syndrome. But sometimes Capgras is seen in the context of other disorders like schizophrenia or bipolar disorder.

Looking at the options, the correct answer would be Capgras syndrome. The other options might be other delusional disorders or types of schizophrenia. Let me check the options again. The options aren't provided, but based on the structure, the correct answer is likely Capgras.

Wait, the patient has acute psychosis, which is more sudden. Capgras is often a symptom rather than a diagnosis. The primary diagnosis would be something like schizophrenia if it's part of a broader picture. But since the question is about the likely diagnosis given the scenario, and the key symptom is the delusion of someone being an imposter, the answer is Capgras syndrome.

So the core concept is delusional misidentification syndromes, with Capgras being the one where someone believes a loved one is an imposter. The correct answer is Capgras syndrome. The other options would be incorrect because they don't fit the specific delusion presented here. The clinical pearl is that Capgras is a specific delusional syndrome often seen in psychotic disorders, and it's important to recognize it as a symptom rather than a standalone diagnosis.

**Core Concept**
This question tests the identification of **delusional misidentification syndromes**, specifically **Capgras syndrome**, which involves the fixed belief that a familiar person has been replaced by an imposter. It commonly occurs in psychotic disorders, schizophrenia, or organic brain syndromes. The key is distinguishing it from other delusional subtypes or acute psychotic episodes.

**Why the Correct Answer is Right**
Capgras syndrome is characterized by the delusion that a close relative or familiar person has been substituted by an identical-looking imposter. In this case, the patient’s belief that his wife is a nurse (an imposter) aligns with this diagnosis. It often arises from **

✓ Correct Answer: A. Capgras syndrome