**Core Concept**
The CAGE questionnaire is a validated screening tool used to assess alcohol use disorders, specifically identifying individuals at risk of alcohol dependence. It evaluates four key symptoms related to alcohol consumption: C (Cannabis), A (Annoyed), G (Guilty), and E (Eye opening) — though clinically, it is most relevant to alcohol misuse.

**Why the Correct Answer is Right**
The CAGE questionnaire was developed to screen for alcohol dependence. It assesses four behavioral and psychological symptoms: **C** (whether the person feels the need to cut down), **A** (anxiety when drinking is stopped), **G** (guilt after drinking), and **E** (eye opening to the clock, indicating impaired judgment). The tool has high sensitivity and specificity in detecting alcohol misuse and is widely used in clinical and forensic settings to identify patients with alcohol dependence.

**Why Each Wrong Option is Incorrect**
Option B: Opiate poisoning is diagnosed by clinical signs like respiratory depression, not screened with CAGE. The tool does not assess drug intoxication or overdose.
Option C: Dhatura poisoning is caused by anticholinergic toxins and presents with delirium, hyperthermia, and muscle rigidity — unrelated to CAGE.
Option D: Barbiturate poisoning causes central nervous system depression, with coma and respiratory failure — no link to CAGE.

**Clinical Pearl / High-Yield Fact**
CAGE is a quick, 4-question tool used in primary care and forensic medicine to screen for alcohol dependence. A "yes" to two or more questions suggests further evaluation for alcohol use disorder.

✓ Correct Answer: A. Alcohol dependence