Substance Use Disorders — MCQs

Substance Use Disorders Indian Medical PG Practice Questions and MCQs

Question 241: Suboxone is a combination of which medications?

A. Naloxone and naltrexone
B. Methadone and buprenorphine
C. Naloxone and buprenorphine (Correct Answer)
D. LAAM and heroin

Explanation: **Explanation:** **Suboxone** is a fixed-dose combination of **Buprenorphine and Naloxone**, typically in a **4:1 ratio**. It is primarily used in the maintenance treatment of Opioid Use Disorder (OUD). * **Buprenorphine:** A high-affinity **partial opioid μ-receptor agonist** and κ-receptor antagonist. It relieves withdrawal symptoms and cravings due to its long half-life and "ceiling effect," which reduces the risk of respiratory depression. * **Naloxone:** A pure **opioid antagonist**. It is added to Suboxone specifically to **prevent intravenous abuse**. When taken sublingually (as intended), naloxone has poor bioavailability and exerts no effect. However, if a user attempts to crush and inject the tablet, the naloxone enters the bloodstream, triggering immediate precipitated withdrawal. **Analysis of Incorrect Options:** * **A. Naloxone and Naltrexone:** Both are antagonists; combining them serves no therapeutic purpose in OUD maintenance. * **B. Methadone and Buprenorphine:** Both are used for OUD, but methadone is a full agonist and buprenorphine is a partial agonist. Combining them can lead to precipitated withdrawal or reduced efficacy. * **D. LAAM and Heroin:** LAAM (Levo-alpha-acetylmethadol) is a long-acting opioid agonist (now largely discontinued); heroin is an illicit drug of abuse. **High-Yield Clinical Pearls for NEET-PG:** 1. **Ceiling Effect:** Buprenorphine has a "ceiling" on respiratory depression, making it safer than methadone in overdose. 2. **Precipitated Withdrawal:** Buprenorphine should only be started when the patient is in **mild-to-moderate withdrawal** (COWS score >12) to avoid displacing full agonists from receptors too abruptly. 3. **Drug of Choice:** While Methadone is often preferred for severe dependence, Suboxone is preferred for office-based treatment due to its lower abuse potential.

Question 242: What is the term for the disorder characterized by an impulse to consume alcohol?

A. Kleptomania
B. Dipsomania (Correct Answer)
C. Pyromania
D. Nymphomania

Explanation: **Explanation:** The correct answer is **Dipsomania (Option B)**. In psychiatry, dipsomania refers to an uncontrollable, often episodic, impulse or craving to consume large amounts of alcohol. Historically, it was used to describe what we now categorize under Alcohol Use Disorder, specifically focusing on the "compulsive" nature of the intake. **Analysis of Options:** * **A. Kleptomania:** An impulse control disorder characterized by the recurrent inability to resist urges to steal objects that are not needed for personal use or monetary value. * **C. Pyromania:** An impulse control disorder where the individual deliberately and repeatedly sets fires to relieve internal tension or for gratification/pleasure. * **D. Nymphomania:** An outdated term (now referred to as hypersexuality or compulsive sexual behavior) describing an uncontrollable or excessive sexual desire in females. **Clinical Pearls for NEET-PG:** 1. **Impulse Control Disorders (ICDs):** These are characterized by a failure to resist an impulse, drive, or temptation to perform an act that is harmful to the person or others. There is a rising sense of tension before the act and a sense of relief/gratification during the act. 2. **Trichotillomania:** Another high-yield ICD involving the compulsive urge to pull out one's own hair. 3. **CAGE Questionnaire:** Remember this screening tool for Alcohol Use Disorder: **C**ut down, **A**nnoyed by criticism, **G**uilty feelings, **E**ye-opener. 4. **Wernicke-Korsakoff Syndrome:** A critical complication of chronic alcohol use due to Thiamine (B1) deficiency, presenting with the triad of Ataxia, Ophthalmoplegia, and Confusion.

Question 243: Which of the following medications is used for the treatment of nicotine dependence?

A. Lithium
B. Clonazepam
C. Methylphenidate
D. Bupropion (Correct Answer)

Explanation: **Explanation:** **Correct Answer: D. Bupropion** **Mechanism and Rationale:** Bupropion is an atypical antidepressant that acts as a **Norepinephrine-Dopamine Reuptake Inhibitor (NDRI)**. In the context of nicotine dependence, it works by increasing dopamine levels in the nucleus accumbens, mimicking the reward effect of nicotine and thereby reducing withdrawal symptoms and cravings. It also acts as an antagonist at nicotinic acetylcholine receptors. It is FDA-approved for smoking cessation and is typically started 1–2 weeks before the patient's "quit date." **Analysis of Incorrect Options:** * **A. Lithium:** A mood stabilizer used primarily as the first-line treatment for Bipolar Affective Disorder (BPAD) and prophylaxis of manic/depressive episodes. It has no role in treating nicotine dependence. * **B. Clonazepam:** A long-acting benzodiazepine used for anxiety disorders, panic attacks, and seizure control. While benzodiazepines may be used in alcohol withdrawal, they are not indicated for nicotine cessation. * **C. Methylphenidate:** A CNS stimulant used primarily for ADHD and Narcolepsy. It increases synaptic dopamine but carries a high risk of abuse and is not used for nicotine dependence. **High-Yield Clinical Pearls for NEET-PG:** * **Varenicline** (a partial agonist at $\alpha4\beta2$ nicotinic receptors) is considered the most effective monotherapy for smoking cessation. * **Contraindications for Bupropion:** It lowers the seizure threshold. It is strictly contraindicated in patients with **Seizure disorders**, **Eating disorders** (Anorexia/Bulimia), or those undergoing abrupt alcohol/sedative withdrawal. * **First-line agents** for nicotine dependence include Nicotine Replacement Therapy (NRT), Bupropion, and Varenicline. * **Second-line agents** include Nortriptyline and Clonidine.

Question 244: What is the mechanism of action of clonidine in opioid withdrawal syndrome?

A. Beta-blocking effect
B. Inhibition of opioid receptor
C. Action on alpha-2 presynaptic nerve endings (Correct Answer)
D. Postsynaptic action

Explanation: ### Explanation **Mechanism of Action (Why Option C is correct):** Opioid withdrawal is characterized by **noradrenergic hyperactivity**. Under normal conditions, opioids inhibit the release of norepinephrine (NE) from the **Locus Coeruleus** (the brain's primary noradrenergic center). During withdrawal, this inhibition is lost, leading to a massive surge of NE. **Clonidine** is a centrally acting **alpha-2 ($\alpha_2$) adrenergic agonist**. These receptors are located on the **presynaptic nerve endings**. When clonidine stimulates these receptors, it activates a negative feedback loop that inhibits the release of norepinephrine. This effectively reduces the autonomic symptoms of withdrawal, such as tachycardia, hypertension, sweating, and restlessness. **Analysis of Incorrect Options:** * **Option A (Beta-blocking effect):** While beta-blockers (like Propranolol) can manage some peripheral symptoms of anxiety or tremors, they do not address the central noradrenergic surge at the $\alpha_2$ receptor level. * **Option B (Inhibition of opioid receptor):** Clonidine does not bind to opioid receptors ($\mu, \kappa, \delta$). Drugs that act here are either agonists (Methadone), partial agonists (Buprenorphine), or antagonists (Naltrexone). * **Option D (Postsynaptic action):** The primary therapeutic effect in withdrawal is mediated via **presynaptic** autoreceptors to decrease neurotransmitter release, rather than postsynaptic stimulation. **NEET-PG High-Yield Pearls:** * **Target Symptoms:** Clonidine is excellent for autonomic symptoms (sweating, diarrhea, tachycardia) but **ineffective** for drug craving, insomnia, or muscle aches. * **Side Effects:** The most common side effect is **hypotension** and sedation; blood pressure monitoring is mandatory. * **Locus Coeruleus:** Remember this as the anatomical site most involved in the physical symptoms of opioid withdrawal. * **Lofexidine:** A newer, more selective $\alpha_2$ agonist with less hypotensive effect than clonidine, also used in withdrawal.

Question 245: Psychosis resulting from chronic amphetamine intake most commonly resembles which of the following conditions?

A. Delirium
B. Mania
C. Paranoid schizophrenia (Correct Answer)
D. Dissociative disorder

Explanation: **Explanation:** **Why Paranoid Schizophrenia is Correct:** Chronic amphetamine use leads to an increase in synaptic dopamine levels, particularly in the mesolimbic pathway. This neurochemical state closely mimics the pathophysiology of schizophrenia. The resulting **Amphetamine-Induced Psychotic Disorder** is characterized by prominent **persecutory delusions**, auditory and visual hallucinations, and ideas of reference. Unlike other drug-induced states, the sensorium remains clear, and the clinical presentation is often indistinguishable from the positive symptoms of **Paranoid Schizophrenia**. **Why Other Options are Incorrect:** * **Delirium:** While acute intoxication can cause confusion, chronic amphetamine psychosis occurs in a state of **clear consciousness** (no clouding of sensorium), which is the hallmark that differentiates it from delirium. * **Mania:** Amphetamines can cause euphoria and hyperactivity, but the specific chronic psychotic state is defined by structured delusions and hallucinations rather than the primary mood disturbance and pressured speech seen in Mania. * **Dissociative Disorder:** This involves a breakdown of memory, identity, or perception (e.g., amnesia, fugue) and is not characterized by the dopamine-driven psychotic symptoms seen in stimulant abuse. **High-Yield Clinical Pearls for NEET-PG:** * **Formication (Cocaine Bugs/Magnan’s Symptom):** A specific tactile hallucination (feeling of insects crawling under the skin) common in both cocaine and amphetamine use. * **Treatment:** The primary treatment for amphetamine psychosis is **Antipsychotics** (D2 receptor antagonists) like Haloperidol, along with acidification of urine to hasten excretion. * **Key Differentiator:** The presence of **visual hallucinations** is more common in drug-induced psychosis than in idiopathic schizophrenia.

Question 246: The intense craving experienced by individuals recovering from chronic alcoholism can be treated by a drug that acts as an antagonist of opioid receptors?

A. Agonist of serotonin receptors
B. Agonist of alpha adrenoceptors
C. Agonist of beta adrenoceptors
D. Antagonist of opioid receptors (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. Antagonist of opioid receptors**. **Mechanism of Action:** The drug referred to in the question is **Naltrexone**. Alcohol consumption triggers the release of endogenous opioids (endorphins) in the brain, which bind to $\mu$-opioid receptors. This process stimulates the mesolimbic dopaminergic pathway (the "reward system"), leading to the pleasurable effects and reinforcement of drinking. Naltrexone, a long-acting **opioid receptor antagonist**, blocks these receptors. By doing so, it reduces the "high" associated with alcohol and significantly diminishes the **intense craving** for it, helping to prevent relapse in chronic alcoholics. **Analysis of Incorrect Options:** * **A. Agonist of serotonin receptors:** While SSRIs (Selective Serotonin Reuptake Inhibitors) are used to treat comorbid depression in alcoholics, they are not the primary treatment for alcohol craving. * **B. Agonist of alpha adrenoceptors:** Drugs like **Clonidine** (alpha-2 agonist) are used to manage autonomic hyperactivity during **acute alcohol withdrawal** (e.g., hypertension, tachycardia) but do not treat long-term craving. * **C. Agonist of beta adrenoceptors:** Beta-blockers (antagonists) are sometimes used for withdrawal tremors, but beta-agonists have no role in treating alcoholism and may worsen anxiety/tachycardia. **High-Yield Clinical Pearls for NEET-PG:** * **Naltrexone:** First-line for craving reduction. Contraindicated in patients with acute hepatitis, liver failure, or those currently using opioids. * **Acamprosate:** Another first-line agent for maintaining abstinence; it acts as an NMDA receptor antagonist and GABA-A enhancer. It is preferred in patients with liver disease but contraindicated in renal failure. * **Disulfiram:** An aldehyde dehydrogenase inhibitor used for **aversion therapy**. It does not reduce craving but causes a toxic reaction (DDR) if alcohol is consumed.

Question 247: All of the following agents are used in the treatment of alcohol dependence, except?

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

Explanation: ### Explanation The correct answer is **A. Flumazenil**. #### Why Flumazenil is the Correct Answer Flumazenil is a competitive **GABA-A receptor antagonist**. Its primary clinical use is the reversal of benzodiazepine overdose or sedation. It has **no role** in the management of alcohol dependence. In fact, using Flumazenil in patients with chronic alcohol or benzodiazepine use can precipitate acute withdrawal seizures. #### Analysis of Other Options (Used in Alcohol Dependence) The other three options are FDA-approved pharmacological interventions for alcohol use disorder: * **Disulfiram (Aversion Therapy):** It inhibits the enzyme **aldehyde dehydrogenase**, leading to the accumulation of acetaldehyde if alcohol is consumed. This causes the unpleasant "Disulfiram-Ethanol Reaction" (flushing, tachycardia, nausea). * **Acamprosate (Anti-craving):** It acts as an NMDA receptor antagonist and GABA-A agonist. It helps maintain abstinence by restoring the chemical balance in the brain (GABA/Glutamate equilibrium) disrupted by chronic alcohol use. It is the drug of choice in patients with **liver disease**. * **Naltrexone (Anti-craving):** An **opioid receptor antagonist** that reduces the "reward" or euphoria associated with drinking. It is particularly effective in reducing the frequency of heavy drinking days. #### NEET-PG High-Yield Clinical Pearls * **Disulfiram** does not reduce cravings; it acts as a psychological deterrent. * **Naltrexone** is contraindicated in patients with acute hepatitis or liver failure (hepatotoxic) and those on opioid analgesics. * **Acamprosate** is contraindicated in patients with severe renal failure (CrCl < 30 ml/min). * **Topiramate** and **Baclofen** are off-label agents often used to reduce alcohol cravings. * **Wernicke’s Encephalopathy** (Thiamine/B1 deficiency) triad: Confusion, Ataxia, Ophthalmoplegia. Always give Thiamine *before* Glucose.

Question 248: Which drug of abuse can cause symptoms similar to paranoid schizophrenia?

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

Explanation: **Explanation:** **Amphetamines** are the correct answer because they directly increase synaptic dopamine levels in the brain (via the mesolimbic pathway). According to the **Dopamine Hypothesis of Schizophrenia**, excessive dopaminergic activity is responsible for positive symptoms. Chronic or high-dose amphetamine use leads to **"Amphetamine Psychosis,"** which is clinically indistinguishable from paranoid schizophrenia, characterized by clear consciousness, paranoid delusions, and auditory/visual hallucinations. **Analysis of Incorrect Options:** * **LSD (Lysergic acid diethylamide):** Primarily acts on serotonin (5-HT2A) receptors. It causes "model psychosis" characterized by vivid visual hallucinations, synesthesia, and depersonalization, rather than the structured paranoid delusions seen in schizophrenia. * **Cannabis:** While cannabis can trigger a brief psychotic episode or exacerbate underlying schizophrenia, its primary acute effects are euphoria, relaxation, or "amotivational syndrome." * **Heroin/Cocaine:** Heroin is an opioid and causes CNS depression/miosis. While Cocaine (a stimulant) can cause "Cocaine Bug" (formication/tactile hallucinations), Amphetamines are the classic prototype for mimicking the full paranoid-hallucinatory syndrome of schizophrenia. **Clinical Pearls for NEET-PG:** * **Distinguishing Feature:** Unlike organic brain syndromes, amphetamine psychosis occurs in a state of **clear consciousness** (no delirium). * **Tactile Hallucinations:** While auditory hallucinations are common in schizophrenia, tactile hallucinations (formication) are highly suggestive of stimulant abuse (Cocaine/Amphetamines). * **Treatment:** The drug of choice for managing acute amphetamine-induced psychosis is **Antipsychotics** (e.g., Haloperidol) and Acidification of urine (to accelerate excretion).

Question 249: Which of the following drugs is not used in the management of alcohol dependence?

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

Explanation: **Explanation:** The management of alcohol dependence involves two phases: detoxification (managing withdrawal) and maintenance (preventing relapse). The drugs listed in options B, C, and D are all FDA-approved for the maintenance phase, whereas **Buspirone** is an anxiolytic with no proven efficacy in treating alcohol dependence. * **Buspirone (Correct Answer):** It is a partial agonist at 5-HT1A receptors used primarily for Generalized Anxiety Disorder (GAD). While it may be used to treat comorbid anxiety in patients with alcohol use disorder, it does not reduce cravings or prevent relapse in alcohol dependence itself. * **Naltrexone:** An opioid antagonist that blocks the "rewarding" effects of alcohol by inhibiting mu-opioid receptors. It reduces the urge to drink and is particularly effective in reducing "heavy drinking" days. * **Acamprosate:** A NMDA receptor antagonist and GABA agonist. It helps maintain abstinence by stabilizing the chemical imbalance (glutamate-GABA) caused by chronic alcohol use. It is the drug of choice in patients with liver disease (as it is renally excreted). * **Disulfiram:** An aldehyde dehydrogenase inhibitor. It acts as an **aversive agent** by causing the accumulation of acetaldehyde if alcohol is consumed, leading to the unpleasant "Disulfiram-Ethanol Reaction" (flushing, tachycardia, nausea). **High-Yield Clinical Pearls for NEET-PG:** * **Drug of choice for Alcohol Withdrawal:** Benzodiazepines (e.g., Chlordiazepoxide, Lorazepam). * **Drug of choice for Relapse Prevention (General):** Naltrexone or Acamprosate. * **Safe in Liver Disease:** Acamprosate (Naltrexone and Disulfiram are hepatotoxic). * **Safe in Renal Failure:** Naltrexone (Acamprosate is contraindicated). * **Disulfiram** requires high patient motivation and supervised administration to be effective.

Question 250: A 34-year-old man is admitted to a psychiatric observation unit complaining of depression and suicidal ideation following a cocaine binge. During his stay, he starts feeling as if insects are crawling under his skin. This is most typical of which of the following phenomena?

A. Depersonalization
B. Dyskinesia
C. Formication (Correct Answer)
D. Illusion

Explanation: **Explanation:** The correct answer is **Formication** (Option C). **Why it is correct:** Formication is a specific type of **tactile hallucination** where a patient experiences the sensation of insects crawling on or under the skin. It is a classic symptom associated with high-dose stimulant use, particularly **cocaine** (where it is famously known as **"Cocaine Bugs"** or Magnan’s sign) and amphetamines. In this clinical scenario, the patient’s recent cocaine binge followed by the sensation of crawling insects is a pathognomonic presentation of cocaine-induced tactile hallucinations. **Why the other options are incorrect:** * **Depersonalization (A):** This is a dissociative symptom where an individual feels detached from their own body or mental processes, as if they are an outside observer. It does not involve tactile sensations. * **Dyskinesia (B):** This refers to involuntary, erratic, or writhing muscle movements (e.g., tardive dyskinesia). It is a motor abnormality, not a sensory perception. * **Illusion (D):** An illusion is a misinterpretation of a **real** external stimulus (e.g., mistaking a rope for a snake). In formication, there is no external stimulus present, making it a hallucination rather than an illusion. **High-Yield Clinical Pearls for NEET-PG:** * **Cocaine Bugs (Magnan’s Sign):** Always associate tactile hallucinations + cocaine use. * **Delirium Tremens:** Tactile hallucinations can also occur during alcohol withdrawal, but the context of a "cocaine binge" makes formication the most specific answer here. * **Ekbom Syndrome:** Also known as Delusional Parasitosis, where the patient has a fixed false belief (delusion) of being infested with parasites, often leading to "matchbox sign" (bringing skin debris in a box to show the doctor). * **Visual Hallucinations:** These are the most common type of hallucinations in organic brain syndromes and substance withdrawal.

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

Practice Questions

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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