Kallu, a 24-year-old occasional alcoholic had got a change in behaviour. He has become suspicious that people are trying to conspire against him, though his father states that there is no reason for his fears. He is getting hallucinations of voices commenting on his actions. What is the most probable diagnosis:March 2013 (f, g)

**Core Concept**
Delirium tremens (DTs) is a severe form of alcohol withdrawal characterized by altered mental status, hallucinations, and disorientation. It occurs typically 48-96 hours after the last drink in individuals with a history of chronic alcohol use.

**Why the Correct Answer is Right**
Kallu's symptoms of suspiciousness, hallucinations of voices, and altered behavior suggest a severe form of alcohol withdrawal. The presence of auditory hallucinations is a key feature of DTs, which typically occurs in individuals with a history of chronic alcohol use. The mechanism behind DTs involves the abrupt cessation of alcohol, leading to an imbalance of neurotransmitters such as gamma-aminobutyric acid (GABA) and glutamate, which are critical for regulating neuronal excitability.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not specifically address the symptoms and context of Kallu's case, which are characteristic of alcohol withdrawal. While it is a form of substance-induced psychosis, it does not fit the clinical scenario described.
**Option B:** This option is incorrect as it does not consider the history of chronic alcohol use and the timing of Kallu's symptoms, which are typical of DTs. While it is a form of substance-induced psychosis, it is less likely given the context.
**Option C:** This option is incorrect as it does not account for Kallu's history of alcohol use and the timing of his symptoms. While it is a form of substance-induced psychosis, it is less likely given the context.
**Option D:** This option is incorrect as it does not specifically address the symptoms and context of Kallu's case, which are characteristic of alcohol withdrawal. While it is a form of substance-induced psychosis, it does not fit the clinical scenario described.

**Clinical Pearl / High-Yield Fact**
Remember the "4 Ds" of DTs: **Delirium**, **Disorientation**, **Dysphoria**, and **Dramatic changes in behavior**. These symptoms typically occur 48-96 hours after the last drink in individuals with a history of chronic alcohol use.

**Correct Answer: D. Delirium tremens.**

✓ Correct Answer: C. Schizophrenia