Substance Use Disorders — MCQs

A known alcoholic is brought to the emergency department by his wife. The person has not consumed alcohol for the past two days due to religious reasons. The person complained of nausea, vomiting, and dizziness. On the second day, he developed seizures that progressed to generalized tonic-clonic seizures (GTCs). Which of the following would be the best medication to manage the patient's seizures?

Q65Medium

A 46-year-old chronic alcoholic, one day after abstinence from alcohol, presents to casualty with restlessness, seizures, coarse tremors, inability to recognize the doctor, and a belief of being in jail. He also complains of uncontrollable fear of being murdered, insomnia, and insects crawling over his body. What is the probable diagnosis?

Q66Easy

Korsakoff's psychosis is seen in which condition?

Q67Easy

Which drug is used in the treatment of smoking and tobacco addiction cessation?

Q68Easy

What is the first-line treatment for smoking cessation?

Q69Easy

What is the common name for 'smack'?

Q70Medium

Which of the following drugs is a common and classical example producing reverse tolerance?

Substance Use Disorders Indian Medical PG Practice Questions and MCQs

Question 61: All of the following drugs are used to prevent relapse after alcohol de-addiction except?

A. Acamprosate
B. Disulfiram
C. Naltrexone
D. Fluoxetine (Correct Answer)

Explanation: **Explanation:** The goal of alcohol de-addiction therapy is to maintain abstinence and prevent relapse. The drugs used for this purpose are classified as **anti-craving agents** or **aversion therapy agents**. **Why Fluoxetine is the correct answer:** Fluoxetine is a Selective Serotonin Reuptake Inhibitor (SSRI) used primarily for Major Depressive Disorder and Anxiety Disorders. While it may be used to treat comorbid depression in an alcoholic patient, it has **no proven efficacy** in reducing alcohol cravings or preventing relapse in the general population of patients with Alcohol Use Disorder. **Analysis of Incorrect Options:** * **Acamprosate (Option A):** A NMDA receptor antagonist and GABA-A agonist. It restores the chemical balance in the brain disrupted by chronic alcohol use. It is considered the drug of choice for maintaining abstinence, especially in patients with liver disease (as it is renally excreted). * **Disulfiram (Option B):** An aldehyde dehydrogenase inhibitor used for **Aversion Therapy**. It causes the accumulation of acetaldehyde if alcohol is consumed, leading to a highly unpleasant "Disulfiram-Ethanol Reaction" (nausea, tachycardia, flushing), thereby deterring the patient from drinking. * **Naltrexone (Option C):** An opioid receptor antagonist that blocks the "reward" or euphoria associated with drinking. It is highly effective in reducing the frequency of heavy drinking and "slip" episodes. **High-Yield Clinical Pearls for NEET-PG:** * **Acamprosate:** Best for maintaining abstinence; safe in liver disease. * **Naltrexone:** Best for reducing cravings and heavy drinking; **contraindicated in liver failure/acute hepatitis.** * **Disulfiram:** Requires a highly motivated patient and supervised administration; must be started at least 12 hours after the last drink. * **Topiramate & Baclofen:** Other second-line agents used off-label for relapse prevention.

Question 62: All of the following drugs are used in alcohol de-addiction except?

A. Naltrexone
B. Acamprostate
C. Disulfiram
D. Opioids (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. Opioids**. Opioids are not used in the treatment of alcohol de-addiction; in fact, alcohol and opioids are both CNS depressants, and their co-administration significantly increases the risk of fatal respiratory depression. **Why the other options are incorrect (Used in Alcohol De-addiction):** * **Naltrexone (Option A):** An opioid antagonist that blocks the $\mu$-opioid receptors. It reduces the "high" or pleasurable effects of alcohol and decreases cravings. It is particularly useful in patients who are still drinking to help reduce consumption. * **Acamprosate (Option B):** A NMDA receptor antagonist and GABA-A agonist. It helps maintain abstinence by restoring the chemical balance in the brain (homeostasis) that was disrupted by chronic alcohol use. It is the drug of choice for maintaining abstinence in patients with liver disease. * **Disulfiram (Option C):** An aldehyde dehydrogenase inhibitor. It acts as an **aversive agent** by causing the accumulation of acetaldehyde if alcohol is consumed, leading to the "Disulfiram-Ethanol Reaction" (flushing, tachycardia, nausea, and vomiting). **High-Yield Clinical Pearls for NEET-PG:** * **First-line drugs for maintaining abstinence:** Naltrexone and Acamprosate. * **Drug of choice for Alcohol Withdrawal:** Benzodiazepines (e.g., Chlordiazepoxide, Diazepam). * **Liver Disease Safety:** Acamprosate is preferred in liver failure (as it is renally excreted), while Naltrexone and Disulfiram are potentially hepatotoxic. * **Wernicke’s Encephalopathy:** Always administer Thiamine (B1) *before* Glucose to prevent precipitating acute neurological symptoms.

Question 63: Which of the following is NOT a medical use of cannabis?

A. Antiepileptic
B. Antiemetic
C. Antiglaucoma
D. Antiplatelet (Correct Answer)

Explanation: **Explanation:** Cannabis contains various cannabinoids, primarily **THC (Tetrahydrocannabinol)** and **CBD (Cannabidiol)**, which interact with the body’s endocannabinoid system (CB1 and CB2 receptors). While cannabis has several therapeutic applications, it has **no established antiplatelet activity**. In fact, some studies suggest that cannabis use may paradoxically increase platelet aggregation and cardiovascular risk in certain contexts, making "Antiplatelet" the correct answer as it is not a medical use. **Analysis of Incorrect Options:** * **Antiepileptic:** CBD (Cannabidiol) is FDA-approved (as Epidiolex) for treating severe, drug-resistant epilepsy syndromes like Dravet syndrome and Lennox-Gastaut syndrome. * **Antiemetic:** THC derivatives (e.g., Dronabinol, Nabilone) are highly effective in treating chemotherapy-induced nausea and vomiting (CINV) when conventional antiemetics fail. * **Antiglaucoma:** Cannabis is known to reduce intraocular pressure (IOP). Although its short duration of action limits its practical use compared to modern eye drops, it remains a recognized physiological effect. **High-Yield Clinical Pearls for NEET-PG:** * **Psychiatric Effects:** Cannabis is associated with "Amotivational Syndrome" (apathy, lack of energy) and can precipitate schizophrenia in genetically vulnerable individuals. * **Physical Signs:** The most common physical sign of acute cannabis intoxication is **conjunctival injection** (red eyes) and increased appetite ("munchies"). * **Withdrawal:** Characterized by irritability, insomnia, and decreased appetite, usually peaking within 48 hours. * **Drug Testing:** The metabolite detected in urine is **11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid** (THC-COOH).

Question 64: A known alcoholic is brought to the emergency department by his wife. The person has not consumed alcohol for the past two days due to religious reasons. The person complained of nausea, vomiting, and dizziness. On the second day, he developed seizures that progressed to generalized tonic-clonic seizures (GTCs). Which of the following would be the best medication to manage the patient's seizures?

A. Sodium valproate
B. Phenytoin
C. Diazepam (Correct Answer)
D. Clonidine

Explanation: **Explanation:** The clinical presentation describes **Alcohol Withdrawal Seizures** (often called "rum fits"). These typically occur 6–48 hours after the last drink, often manifesting as generalized tonic-clonic seizures (GTCS). **1. Why Diazepam is the Correct Answer:** The underlying pathophysiology of alcohol withdrawal is a state of CNS hyperexcitability caused by the sudden removal of alcohol (a GABA agonist and NMDA antagonist). This leads to GABA-receptor downregulation and NMDA-receptor upregulation. **Benzodiazepines (BZDs)** like **Diazepam** are the gold standard because they are cross-tolerant with alcohol; they enhance GABAergic transmission, effectively "substituting" for the alcohol and stabilizing the neuronal membranes to prevent further seizures and progression to Delirium Tremens. **2. Why Other Options are Incorrect:** * **Phenytoin:** It is notoriously **ineffective** for alcohol withdrawal seizures because it does not act on the GABA-NMDA imbalance. It is only indicated if the patient has a comorbid primary epilepsy disorder. * **Sodium Valproate:** While an anticonvulsant, it is not the first-line treatment for acute withdrawal stabilization and carries a risk of hepatotoxicity, which is a concern in chronic alcoholics. * **Clonidine:** This is an alpha-2 agonist used to manage **autonomic hyperactivity** (tachycardia, hypertension) during withdrawal, but it has no anti-epileptic properties and cannot prevent seizures or delirium. **Clinical Pearls for NEET-PG:** * **Timeframe:** Alcohol withdrawal seizures usually occur within **12–48 hours**; Delirium Tremens occurs within **48–96 hours**. * **Drug of Choice:** Long-acting BZDs (Diazepam, Chlordiazepoxide) are preferred due to smoother tapering. * **Liver Disease Exception:** If the patient has cirrhosis or liver failure, use **LOT** (Lorazepam, Oxazepam, Temazepam) as they undergo extrahepatic metabolism. * **Kindling Effect:** Each episode of withdrawal increases the risk and severity of future seizures.

Question 65: A 46-year-old chronic alcoholic, one day after abstinence from alcohol, presents to casualty with restlessness, seizures, coarse tremors, inability to recognize the doctor, and a belief of being in jail. He also complains of uncontrollable fear of being murdered, insomnia, and insects crawling over his body. What is the probable diagnosis?

A. Alcoholic seizures (rum fits)
B. Korsakoff's psychosis
C. Delirium tremens (Correct Answer)
D. Alcoholic hallucinosis

Explanation: ### Explanation The patient is presenting with a classic case of **Delirium Tremens (DT)**, the most severe form of alcohol withdrawal. **1. Why Delirium Tremens is correct:** DT typically occurs **48–96 hours** after the last drink (though it can start earlier). The diagnosis is confirmed by the presence of: * **Clouding of consciousness/Disorientation:** "Inability to recognize the doctor" and "belief of being in jail." * **Autonomic Hyperactivity:** Restlessness, insomnia, and tremors. * **Perceptual Disturbances:** Visual and tactile hallucinations ("insects crawling over body" – **formication**) and delusions of persecution ("fear of being murdered"). * **Seizures:** Often precede or accompany DT. **2. Why other options are incorrect:** * **Alcoholic Seizures (Rum Fits):** These are generalized tonic-clonic seizures occurring **6–48 hours** after abstinence. While this patient has seizures, the presence of delirium (disorientation) and hallucinations points toward DT. * **Korsakoff’s Psychosis:** This is a chronic amnestic syndrome characterized by **anterograde amnesia and confabulation** due to Thiamine (B1) deficiency. It does not present with acute autonomic instability or hallucinations. * **Alcoholic Hallucinosis:** This occurs in a **clear sensorium** (the patient is oriented to time, place, and person). In this case, the patient is disoriented, which distinguishes DT from hallucinosis. **3. High-Yield Clinical Pearls for NEET-PG:** * **Timeline of Withdrawal:** Tremors (6-12h) → Seizures (6-48h) → Hallucinosis (12-48h) → Delirium Tremens (48-96h). * **Formication:** The sensation of insects crawling on the skin is also known as **"Magnan’s Sign"** (common in cocaine and alcohol withdrawal). * **Drug of Choice:** **Benzodiazepines** (Chlordiazepoxide or Diazepam) are the gold standard for management. In patients with liver failure, use **LOT** (Lorazepam, Oxazepam, Temazepam). * **Mortality:** Untreated DT has a mortality rate of up to 20%, usually due to cardiovascular collapse or hyperthermia.

Question 66: Korsakoff's psychosis is seen in which condition?

A. Acute alcoholism
B. Carbon monoxide poisoning
C. Chronic alcoholism (Correct Answer)
D. Multiple sclerosis

Explanation: **Explanation:** **Korsakoff’s Psychosis** is a late-stage manifestation of **Wernicke-Korsakoff Syndrome (WKS)**, primarily caused by a severe deficiency of **Thiamine (Vitamin B1)**. In the context of **Chronic Alcoholism (Option C)**, thiamine deficiency occurs due to poor dietary intake, impaired gastrointestinal absorption, and reduced hepatic storage of the vitamin. While Wernicke’s Encephalopathy is the acute, reversible phase, Korsakoff’s Psychosis is the chronic, often irreversible stage characterized by selective anterograde and retrograde amnesia and **confabulation** (filling memory gaps with fabricated stories). **Analysis of Incorrect Options:** * **Option A (Acute Alcoholism):** Acute intoxication presents with cerebellar ataxia and slurred speech but does not cause the structural brain damage (atrophy of mammillary bodies) required for Korsakoff’s. * **Option B (Carbon Monoxide Poisoning):** While CO poisoning causes hypoxia and can lead to delayed neuropsychiatric sequelae (like Parkinsonism or globus pallidus lesions), it is not the classic cause of Korsakoff’s. * **Option D (Multiple Sclerosis):** This is a demyelinating disease of the CNS presenting with optic neuritis or sensory-motor deficits, not a thiamine-related amnestic syndrome. **High-Yield Clinical Pearls for NEET-PG:** 1. **The Triad of Wernicke’s:** Confusion, Ataxia, and Ophthalmoplegia (6th nerve palsy). 2. **Pathology:** Characterized by hemorrhage and atrophy of the **Mammillary bodies** and dorsomedial nucleus of the thalamus. 3. **The "Glucose Rule":** Always administer Thiamine *before* Glucose in a chronic alcoholic to prevent precipitating Wernicke’s Encephalopathy. 4. **Confabulation:** This is the hallmark psychiatric feature of Korsakoff’s, used by the patient to maintain self-esteem despite memory loss.

Question 67: Which drug is used in the treatment of smoking and tobacco addiction cessation?

A. Varenicline (Correct Answer)
B. Acamprosate
C. Baclofen
D. Naltrexone

Explanation: **Explanation:** **Varenicline** is the correct answer as it is a first-line pharmacological agent specifically approved for smoking cessation. Its mechanism of action involves being a **selective partial agonist at the α4β2 nicotinic acetylcholine receptors**. By partially stimulating these receptors, it reduces withdrawal symptoms (agonist effect) while simultaneously blocking the binding of nicotine from cigarettes, thereby reducing the "reward" or reinforcement associated with smoking (antagonist effect). **Analysis of Incorrect Options:** * **Acamprosate:** Used for the maintenance of abstinence in **Alcohol Use Disorder**. It acts as a glutamate modulator (NMDA receptor antagonist) to restore the GABA/glutamate balance disrupted by chronic alcohol use. * **Baclofen:** A GABA-B receptor agonist primarily used as a muscle relaxant. While it is sometimes used off-label to reduce cravings in alcohol or opioid dependence, it is not a standard treatment for tobacco cessation. * **Naltrexone:** An opioid receptor antagonist used in the treatment of **Alcohol Dependence** (to reduce craving/heavy drinking) and **Opioid Dependence** (to prevent relapse). **High-Yield Clinical Pearls for NEET-PG:** * **First-line agents for Smoking Cessation:** Nicotine Replacement Therapy (NRT), Varenicline, and Bupropion (an atypical antidepressant). * **Varenicline Side Effects:** Most common is nausea; it was previously associated with neuropsychiatric symptoms (suicidal ideation), though recent data suggests these risks are lower than initially feared. * **Bupropion Contraindication:** Avoid in patients with a history of seizures or eating disorders (bulimia/anorexia), as it lowers the seizure threshold. * **Cytisine:** Another partial nicotinic agonist (similar to Varenicline) gaining importance in recent literature.

Question 68: What is the first-line treatment for smoking cessation?

A. Nortriptyline
B. Clonidine
C. Varenicline (Correct Answer)
D. Buspirone

Explanation: **Explanation:** Smoking cessation is a high-yield topic in NEET-PG, focusing on pharmacological interventions that target the brain's reward system. **Why Varenicline is the Correct Answer:** Varenicline is currently considered the most effective monotherapy for smoking cessation. It acts as a **selective partial agonist at the α4β2 nicotinic acetylcholine receptors**. * **Agonist effect:** It provides a low-level release of dopamine, which helps mitigate withdrawal symptoms and cravings. * **Antagonist effect:** It blocks nicotine from binding to the receptor, thereby preventing the "reward" or "buzz" associated with smoking a cigarette (reinforcement). **Analysis of Incorrect Options:** * **A. Nortriptyline:** This is a Tricyclic Antidepressant (TCA) considered a **second-line** agent. It is used only when first-line therapies (Varenicline, Bupropion, or Nicotine Replacement Therapy) are ineffective or contraindicated. * **B. Clonidine:** An alpha-2 agonist used as a **second-line** treatment. While it reduces sympathetic overactivity during withdrawal, its side-effect profile (hypotension, sedation) limits its use. * **D. Buspirone:** An anxiolytic (5-HT1A partial agonist) that has **not** shown significant efficacy in smoking cessation trials and is not recommended for this purpose. **High-Yield Clinical Pearls for NEET-PG:** 1. **First-line agents:** Varenicline, Bupropion (atypical antidepressant), and Nicotine Replacement Therapy (NRT). 2. **Varenicline Side Effects:** Most common is **nausea** (dose-dependent). It was previously linked to neuropsychiatric symptoms (suicidal ideation), though recent data suggests this risk is lower than initially feared. 3. **Bupropion Contraindications:** Avoid in patients with a history of **seizures** or **eating disorders** (bulimia/anorexia) as it lowers the seizure threshold. 4. **Combination Therapy:** Combining Varenicline with NRT or using two forms of NRT (patch + gum) is often more effective than monotherapy.

Question 69: What is the common name for 'smack'?

A. Heroin (Correct Answer)
B. Cocaine
C. Opium
D. None of the above

Explanation: **Explanation:** **Heroin (Option A)** is the correct answer. Heroin is a semi-synthetic opioid synthesized from morphine. In the illicit drug market, it is most commonly referred to by the street name **'Smack'**. It is also frequently called 'Brown Sugar' (when in adulterated form), 'Horse', or 'Junk'. Chemically, heroin is **Diacetylmorphine**. It is highly lipid-soluble, allowing it to cross the blood-brain barrier rapidly, which accounts for the intense "rush" experienced by users. **Why other options are incorrect:** * **Cocaine (Option B):** This is a potent stimulant derived from the coca plant. Its common street names include **'Coke'**, 'Snow', 'Crack' (the freebase form), and 'Candy'. * **Opium (Option C):** This is the raw extract from the poppy plant (*Papaver somniferum*). While it is the precursor to heroin, it is generally referred to as 'Afeem' or 'Lachha' rather than 'smack'. **High-Yield Clinical Pearls for NEET-PG:** 1. **Mechanism:** Heroin acts primarily on **mu (μ) opioid receptors**. 2. **Triad of Opioid Overdose:** Pinpoint pupils (miosis), respiratory depression, and altered sensorium (coma). 3. **Withdrawal Symptoms:** Characterized by lacrimation, rhinorrhea, yawning, piloerection (gooseflesh), and dilated pupils (mydriasis). 4. **Management:** **Naloxone** is the drug of choice for acute overdose. For substitution therapy (detoxification), **Methadone** or **Buprenorphine** are used. 5. **Golden Brown:** A specific form of high-purity heroin.

Question 70: Which of the following drugs is a common and classical example producing reverse tolerance?

A. LSD
B. Cannabis
C. Alcohol (Correct Answer)
D. Nicotine

Explanation: **Explanation** The correct answer is **Alcohol**. **Understanding Reverse Tolerance (Sensitization)** Reverse tolerance occurs when a lower dose of a substance produces the same or even more intense effects than previously achieved with higher doses. In the context of **Alcohol**, this is a classical clinical feature of end-stage chronic alcoholism. It is primarily due to **severe liver damage (cirrhosis)**. As the liver’s metabolic capacity declines, it can no longer efficiently metabolize alcohol via alcohol dehydrogenase. Consequently, even small amounts of alcohol remain in the bloodstream for longer periods, leading to prolonged and heightened intoxication. **Analysis of Incorrect Options:** * **LSD (Option A):** Characterized by **tachyphylaxis** (rapidly developing tolerance). Taking LSD on consecutive days leads to a very quick decrease in effect, requiring a "washout" period to regain sensitivity. * **Cannabis (Option B):** Generally produces standard tolerance with chronic use. While some studies suggest behavioral sensitization, it is not the "classical" example used in medical examinations. * **Nicotine (Option D):** Produces rapid tolerance and severe physical dependence. It does not exhibit reverse tolerance; users typically increase their consumption over time to achieve the same stimulant effect. **High-Yield NEET-PG Pearls:** * **Tolerance:** A state where increased doses are needed to achieve the same effect. * **Cross-tolerance:** Tolerance to one drug (e.g., Alcohol) leads to tolerance to another in the same class (e.g., Benzodiazepines). * **Wernicke-Korsakoff Syndrome:** A key complication of chronic alcohol use due to Thiamine (B1) deficiency. * **Disulfiram:** Used in aversion therapy; it inhibits aldehyde dehydrogenase, causing a buildup of acetaldehyde.

Practice by Chapter

Neurobiology of Addiction

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Alcohol Use Disorder

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Opioid Use Disorder

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Cannabis Use Disorder

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Stimulant Use Disorders

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Sedative, Hypnotic, and Anxiolytic Use Disorders

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Tobacco Use Disorder

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Hallucinogen-Related Disorders

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Substance Withdrawal Syndromes

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Pharmacotherapy for Substance Use Disorders

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Psychosocial Interventions

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Dual Diagnosis Management

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