Substance Use Disorders — MCQs

Substance Use Disorders Indian Medical PG Practice Questions and MCQs

Question 11: What is meant by 'crash' in the context of cocaine use?

A. Depression following cocaine use (Correct Answer)
B. Nasal ulcers following cocaine use
C. Myocardial infarction following cocaine use
D. Sudden infant death syndrome following cocaine use

Explanation: **Explanation:** The term **'crash'** refers to the acute withdrawal phase that occurs immediately after a period of heavy cocaine use (a "binge"). Cocaine is a potent CNS stimulant that increases synaptic concentrations of dopamine, norepinephrine, and serotonin. Once the drug's effects wear off, there is a relative depletion of these neurotransmitters, leading to a state of **post-intoxication depression**. **Why Option A is correct:** The 'crash' is characterized by symptoms diametrically opposite to the drug's effects. These include intense dysphoria, profound depression, fatigue, irritability, and increased sleep (hypersomnia). In severe cases, suicidal ideation may occur during this phase. **Why other options are incorrect:** * **Option B:** Nasal ulcers and septal perforation are chronic local complications of intranasal cocaine use (snorting) due to its potent vasoconstrictive properties, but they are not termed a 'crash'. * **Option C:** Myocardial infarction is a life-threatening acute medical complication of cocaine toxicity (due to coronary vasospasm and increased oxygen demand), not a withdrawal phenomenon. * **Option D:** While cocaine use during pregnancy (Crack babies) is associated with various neonatal issues, it is not the definition of a 'crash'. **High-Yield Clinical Pearls for NEET-PG:** * **Cocaine Mechanism:** Blocks the reuptake of biogenic amines (Dopamine, NE, 5-HT). * **Formication (Magnan’s Sign):** The tactile hallucination of insects crawling under the skin; a classic sign of cocaine intoxication. * **Pupillary Sign:** Cocaine causes **Mydriasis** (dilated pupils) during intoxication, unlike opioids which cause Miosis. * **Treatment:** There is no FDA-approved medication for cocaine dependence; psychosocial interventions are the mainstay. For acute agitation, benzodiazepines are used.

Question 12: A patient with a known history of alcohol dependence experiences a seizure for the first time 12 to 18 hours after their last drink. What is the most appropriate treatment for this condition, often referred to as "rum fits"?

A. Phenytoin
B. IV Thiamine
C. Lorazepam (Correct Answer)
D. Clobazam

Explanation: **Explanation:** The clinical presentation describes **Alcohol Withdrawal Seizures**, colloquially known as **"rum fits."** These typically occur 6 to 48 hours after the last drink and are characterized by generalized tonic-clonic seizures (GTCS). **1. Why Lorazepam is the correct answer:** The underlying pathophysiology of alcohol withdrawal involves a state of CNS hyperexcitability due to the downregulation of GABA receptors and upregulation of NMDA (glutamate) receptors. **Benzodiazepines (BZDs)**, such as Lorazepam, are the gold standard treatment because they are cross-tolerant with alcohol. They enhance GABAergic neurotransmission, effectively "calming" the brain and increasing the seizure threshold. Lorazepam is often preferred in clinical settings due to its predictable metabolism and lack of active metabolites, making it safer if there is underlying liver dysfunction. **2. Why other options are incorrect:** * **Phenytoin:** It is **ineffective** for alcohol withdrawal seizures. These seizures are caused by metabolic withdrawal, not a primary focal epilepsy trigger. Phenytoin does not act on the GABA-receptor complex. * **IV Thiamine:** While essential to prevent Wernicke-Korsakoff syndrome, thiamine does not treat or prevent seizures. It should be given *before* glucose, but it is not the primary treatment for "rum fits." * **Clobazam:** While a BZD, it is typically used as an adjunctive treatment for epilepsy or for milder anxiety. For acute withdrawal seizures, rapid-acting BZDs like Lorazepam or Diazepam are preferred. **Clinical Pearls for NEET-PG:** * **Timing:** Alcohol withdrawal seizures peak at **12–24 hours**. * **Nature:** Usually a single GTCS or a brief cluster; if status epilepticus occurs, look for other causes (e.g., trauma, infection). * **Kindling Effect:** Each subsequent withdrawal episode increases the risk and severity of future seizures. * **Delirium Tremens (DT):** Occurs later (48–96 hours). Seizures usually precede DT. * **DOC:** Long-acting BZDs (Chlordiazepoxide/Diazepam) are preferred for prophylaxis; short-acting (Lorazepam/Oxazepam) are preferred in liver failure.

Question 13: An addict presents with increased sweating, lacrimation, diarrhea, yawning, and rhinorrhea. These symptoms may occur due to withdrawal of?

A. Heroin (Correct Answer)
B. Cocaine
C. Cannabis
D. Alcohol

Explanation: **Explanation:** The clinical presentation of **lacrimation (tearing), rhinorrhea (runny nose), yawning, sweating, and diarrhea** is the classic "flu-like" constellation of symptoms diagnostic of **Opioid Withdrawal**. **1. Why Heroin is Correct:** Heroin is a potent opioid. When a dependent user stops intake, the central nervous system—which was previously suppressed—becomes hyperactive. This leads to autonomic instability. Key signs include: * **Secretory hyperactivity:** Lacrimation, rhinorrhea, and sweating. * **Gastrointestinal distress:** Diarrhea, nausea, and abdominal cramps. * **Neuromuscular/Behavioral:** Yawning, piloerection (goosebumps—the origin of the term "cold turkey"), and mydriasis (dilated pupils). **2. Why the Incorrect Options are Wrong:** * **Cocaine:** Withdrawal typically presents with "the crash"—dysphoria, fatigue, increased appetite, and vivid unpleasant dreams, rather than autonomic hypersecretion. * **Cannabis:** Withdrawal is mild, involving irritability, insomnia, and decreased appetite. * **Alcohol:** Withdrawal is characterized by tremors, tachycardia, hypertension, and in severe cases, seizures or Delirium Tremens. It does not typically feature yawning or rhinorrhea. **3. High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic:** Remember "Wet" symptoms (tears, sweat, runny nose, diarrhea) for Opioid withdrawal. * **Pupils:** Opioid **Intoxication** = Pinpoint pupils (Miosis); Opioid **Withdrawal** = Dilated pupils (Mydriasis). * **Treatment:** Clonidine (alpha-2 agonist) can be used to manage autonomic symptoms; Methadone or Buprenorphine are used for long-term detoxification. * **Fact:** While extremely distressing, opioid withdrawal is rarely life-threatening, unlike alcohol or benzodiazepine withdrawal.

Question 14: All of the following drugs are used in opioid dependence, except?

A. LAAM
B. Buprenorphine
C. Methadone
D. Nalorphine (Correct Answer)

Explanation: **Explanation:** The management of opioid dependence involves two main strategies: **Agonist Substitution Therapy** (maintenance) and **Antagonist Therapy** (relapse prevention). **Why Nalorphine is the correct answer:** Nalorphine is a mixed opioid agonist-antagonist. Historically, it was used to treat opioid overdose, but it is **not** used in the management of dependence. This is because it can precipitate **acute withdrawal symptoms** in opioid-dependent individuals and has significant psychotomimetic side effects (like dysphoria and hallucinations), making it clinically unsuitable for long-term treatment. **Analysis of other options:** * **LAAM (Levo-alpha-acetylmethadol):** A long-acting synthetic opioid agonist. Due to its long half-life, it can be administered 3 times a week, making it effective for maintenance therapy (though it is less commonly used now due to cardiotoxicity/QT prolongation). * **Buprenorphine:** A partial $\mu$-opioid agonist. It is a gold standard for "office-based" detoxification and maintenance because it has a "ceiling effect" on respiratory depression, making it safer than full agonists. * **Methadone:** A long-acting full $\mu$-opioid agonist. It is the most widely used drug for Opioid Substitution Therapy (OST) globally, preventing withdrawal and reducing "drug-seeking" behavior. **NEET-PG High-Yield Pearls:** * **Drug of choice for Opioid Overdose:** Naloxone (Short-acting antagonist). * **Drug of choice for Relapse Prevention:** Naltrexone (Long-acting antagonist). * **Clonidine:** An $\alpha_2$ agonist used to manage the *autonomic symptoms* of opioid withdrawal (tachycardia, hypertension, sweating) but does not treat craving. * **Buprenorphine + Naloxone:** Often combined in a 4:1 ratio to prevent intravenous abuse of the sublingual tablet.

Question 15: All of the following are hallucinogens except?

A. Mescaline
B. Phencyclidine
C. Ketamine
D. Pentostatin (Correct Answer)

Explanation: **Explanation:** The correct answer is **Pentostatin**. This question tests the ability to differentiate between psychoactive substances and unrelated pharmacological agents. **1. Why Pentostatin is the correct answer:** Pentostatin is **not a hallucinogen**; it is a chemotherapy medication. Specifically, it is a purine analog that acts as an **adenosine deaminase inhibitor**. It is primarily used in the treatment of Hairy Cell Leukemia. It has no primary action on the central nervous system that produces hallucinogenic effects. **2. Analysis of incorrect options (Hallucinogens):** * **Mescaline (Option A):** A classic hallucinogen derived from the Peyote cactus. It is a phenethylamine that acts primarily as a 5-HT2A receptor agonist. * **Phencyclidine (PCP) (Option B):** Known as "Angel Dust," it is a dissociative anesthetic. It acts as an NMDA receptor antagonist and is notorious for causing vertical/rotational nystagmus and aggressive behavior. * **Ketamine (Option C):** A "dissociative hallucinogen" and NMDA receptor antagonist. It is used medically as an anesthetic but is a common drug of abuse, causing "K-hole" experiences (depersonalization and derealization). **High-Yield Clinical Pearls for NEET-PG:** * **Classification:** Hallucinogens are divided into **Psychedelics** (LSD, Psilocybin, Mescaline), **Dissociatives** (PCP, Ketamine), and **Deliriants** (Atropine, Datura). * **LSD (Lysergic Acid Diethylamide):** The most potent hallucinogen; acts on 5-HT2A receptors. It does not cause physical dependence or withdrawal. * **Flashbacks:** Also known as Hallucinogen Persisting Perception Disorder (HPPD), these are spontaneous recurrences of sensory distortions weeks or months after drug use. * **PCP Toxicity:** Look for the triad of **Nystagmus, Hypertension, and Agitation/Violence**.

Question 16: Which drug is useful in the long-term treatment of alcohol dependence?

A. Acamprosate (Correct Answer)
B. Chlordiazepoxide
C. Flumazenil
D. Imipramine

Explanation: **Explanation:** The management of Alcohol Use Disorder is divided into two phases: **Acute Withdrawal** and **Relapse Prevention (Maintenance)**. **Why Acamprosate is correct:** Acamprosate is a first-line FDA-approved drug for the **long-term maintenance** of abstinence in alcohol-dependent patients. It acts as a GABA agonist and an NMDA antagonist, effectively stabilizing the chemical imbalance in the brain caused by chronic alcohol use (the "post-withdrawal" hyper-excitability). It is particularly useful in patients with liver disease as it is primarily excreted by the kidneys. **Why the other options are incorrect:** * **Chlordiazepoxide:** This is a long-acting benzodiazepine used as the drug of choice for **acute alcohol withdrawal** to prevent seizures and delirium tremens. It is not used for long-term maintenance due to its high potential for dependence. * **Flumazenil:** This is a competitive GABA-A receptor antagonist used specifically for the reversal of **Benzodiazepine overdose**. It has no role in treating alcohol dependence. * **Imipramine:** This is a Tricyclic Antidepressant (TCA). While it may treat comorbid depression, it is not a specific treatment for alcohol dependence. **High-Yield Clinical Pearls for NEET-PG:** * **Disulfiram:** An aversive agent that inhibits *Aldehyde Dehydrogenase*, causing a buildup of acetaldehyde (Disulfiram-like reaction). It requires high patient motivation. * **Naltrexone:** An opioid antagonist that reduces the "craving" and "reward" associated with drinking. It is contraindicated in acute hepatitis or liver failure. * **Acamprosate:** The preferred drug for patients with **liver impairment** but must be avoided in **renal failure** (CrCl < 30 ml/min). * **Wernicke’s Encephalopathy:** Always remember to supplement **Thiamine (B1)** before glucose in alcoholics to prevent neurological complications.

Question 17: All of the following are used for the detoxification of opioids except?

A. Methadone
B. Clonidine
C. Buprenorphine
D. Pethidine (Correct Answer)

Explanation: **Explanation:** The goal of opioid detoxification is to manage withdrawal symptoms by either using long-acting opioid agonists (substitution therapy) or non-opioid medications that suppress autonomic hyperactivity. **Why Pethidine (Option D) is the correct answer:** Pethidine (Meperidine) is a synthetic opioid with a **very short half-life** and a toxic metabolite called **normeperidine**. Due to its short duration of action, it would cause rapid fluctuations in blood levels, leading to frequent withdrawal spikes rather than stabilization. Furthermore, high doses or chronic use can lead to normeperidine accumulation, causing CNS irritability and seizures. Therefore, it has no role in detoxification protocols. **Analysis of other options:** * **Methadone (Option A):** A long-acting μ-opioid agonist. Its long half-life (24–36 hours) allows for a smooth, controlled tapering process, preventing severe withdrawal symptoms. * **Clonidine (Option B):** An alpha-2 adrenergic agonist. It is a **non-opioid** treatment used to manage the autonomic symptoms of withdrawal (tachycardia, hypertension, sweating, and restlessness) by reducing norepinephrine release. * **Buprenorphine (Option C):** A partial μ-opioid agonist. It has a high affinity for receptors but low intrinsic activity, making it safer than methadone regarding respiratory depression while effectively suppressing cravings. **NEET-PG High-Yield Pearls:** * **Gold Standard for Maintenance:** Methadone is traditionally the gold standard for opioid substitution therapy (OST). * **Lofexidine:** A newer alpha-2 agonist (similar to clonidine) specifically FDA-approved for opioid withdrawal with fewer hypotensive side effects. * **Pethidine Contraindication:** Never mix Pethidine with **MAO Inhibitors**, as it can trigger a life-threatening serotonin syndrome or "excitatory" reaction.

Question 18: Which of the following is NOT a symptom of cocaine withdrawal?

A. Dysphoria
B. Fatigue
C. Disturbed sleep
D. Hallucinations of insects under the skin (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. Hallucinations of insects under the skin.** **Why it is the correct answer:** Hallucinations of insects crawling under the skin (known as **Formication** or **"Cocaine Bugs"**) are a classic symptom of **Cocaine Intoxication**, not withdrawal. This tactile hallucination occurs due to the potent dopaminergic surge in the CNS during acute use. In contrast, cocaine withdrawal (the "crash") is characterized by a state of physiological and psychological depletion. **Why the other options are incorrect:** Cocaine withdrawal typically presents with symptoms that are the polar opposite of the drug’s stimulant effects: * **A. Dysphoria:** As dopamine levels plummet after a binge, patients experience profound "anhedonia" (inability to feel pleasure) and a depressed mood (dysphoria). * **B. Fatigue:** The intense stimulation of the sympathetic nervous system is followed by "crashing," leading to extreme exhaustion and psychomotor retardation. * **C. Disturbed sleep:** Withdrawal is characterized by sleep disturbances, specifically **insomnia followed by hypersomnia** (excessive sleeping) and vivid, unpleasant dreams. **High-Yield NEET-PG Clinical Pearls:** * **Cocaine Withdrawal:** Unlike alcohol or opioid withdrawal, cocaine withdrawal is rarely life-threatening and does not typically require pharmacological intervention. The primary risk is **suicidal ideation** due to severe dysphoria. * **Formication:** Also called **Magnan’s Sign**. It is a key diagnostic clue for stimulant psychosis (Cocaine or Amphetamines). * **Physical Signs of Intoxication:** Look for mydriasis (dilated pupils), tachycardia, hypertension, and potential chest pain (due to coronary vasospasm). * **Treatment:** For acute intoxication/agitation, **Benzodiazepines** are the first-line treatment. Avoid Beta-blockers due to the risk of unopposed alpha-adrenergic stimulation.

Question 19: Xylene and toluene are types of which of the following?

A. Inhalants (Correct Answer)
B. Hallucinogens
C. Stimulants
D. Anabolic androgenic steroids

Explanation: ### Explanation **Correct Option: A. Inhalants** Xylene and toluene are volatile organic solvents found in common household and industrial products like glue, spray paints, paint thinners, and gasoline. These substances are classified as **Inhalants**. When inhaled, they rapidly cross the blood-brain barrier due to their high lipid solubility, acting as CNS depressants. Toluene is the most common solvent found in inhalants and is known to enhance GABAergic transmission while inhibiting NMDA receptors. **Why other options are incorrect:** * **B. Hallucinogens:** These include substances like LSD, Psilocybin, and Phencyclidine (PCP). While inhalants can cause distortions in perception, they do not belong to the pharmacological class of classic hallucinogens. * **C. Stimulants:** These include drugs like Cocaine and Amphetamines, which increase CNS activity by raising levels of dopamine and norepinephrine. Inhalants generally produce a "high" followed by CNS depression, similar to alcohol. * **D. Anabolic androgenic steroids:** These are synthetic derivatives of testosterone used to increase muscle mass and athletic performance; they have no volatile properties. **High-Yield Clinical Pearls for NEET-PG:** * **Sudden Sniffing Death Syndrome:** The most feared acute complication of inhalant abuse, caused by fatal cardiac arrhythmias due to myocardial sensitization to catecholamines. * **Chronic Toxicity:** Long-term toluene abuse is associated with **leukoencephalopathy** (white matter damage) and peripheral neuropathy. * **Glue Sniffer’s Rash:** An eczematous dermatitis found around the nose and mouth. * **Common User Profile:** Typically seen in adolescents from low socioeconomic backgrounds due to easy accessibility and low cost.

Question 20: What is the most commonly abused substance that causes dependence?

A. Cocaine
B. Heroin (Correct Answer)
C. Amphetamine
D. Cannabis

Explanation: ### Explanation **Correct Answer: B. Heroin** The core concept behind this question is the **addictive potential** (reinforcement strength) of a substance. Heroin, a semi-synthetic opioid, is considered the most addictive substance among the options provided. It has an extremely high potential for dependence because it is highly lipid-soluble, allowing it to cross the blood-brain barrier rapidly. This results in an intense, immediate "rush" by activating the brain's reward system (mu-opioid receptors and dopamine release in the nucleus accumbens), leading to rapid neuroadaptation and severe physical and psychological dependence. **Analysis of Incorrect Options:** * **A. Cocaine:** While cocaine is a potent stimulant with high psychological dependence, its physical withdrawal syndrome is generally less severe than that of opioids like heroin. * **C. Amphetamine:** These stimulants increase synaptic dopamine and have significant abuse potential, but they typically rank lower than heroin in terms of the speed and intensity of dependence formation. * **D. Cannabis:** Although it is one of the most *frequently used* illicit drugs globally, its dependence potential is significantly lower than that of opioids or stimulants. **NEET-PG High-Yield Pearls:** * **Most common substance abuse (General Population):** Caffeine (Global), Tobacco/Alcohol (India). * **Most common illicit drug used:** Cannabis. * **Highest dependence potential:** Heroin (Opioids) > Cocaine > Nicotine. * **Drug of Choice for Opioid Overdose:** Naloxone (Opioid antagonist). * **Drug of Choice for Opioid Withdrawal/Maintenance:** Methadone or Buprenorphine. * **Clinical Sign:** Pinpoint pupils (miosis) is a classic sign of opioid overdose (except for Pethidine).

Practice by Chapter

Neurobiology of Addiction

Practice Questions

Alcohol Use Disorder

Practice Questions

Opioid Use Disorder

Practice Questions

Cannabis Use Disorder

Practice Questions

Stimulant Use Disorders

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Sedative, Hypnotic, and Anxiolytic Use Disorders

Practice Questions

Tobacco Use Disorder

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Hallucinogen-Related Disorders

Practice Questions

Substance Withdrawal Syndromes

Practice Questions

Pharmacotherapy for Substance Use Disorders

Practice Questions

Psychosocial Interventions

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Dual Diagnosis Management

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