Substance Use Disorders — MCQs

Substance Use Disorders Indian Medical PG Practice Questions and MCQs

Question 41: A patient reports a sensation of insects crawling on or under the skin. This phenomenon is known as a specific type of hallucination. Which of the following conditions is most commonly associated with this sensory experience?

A. Alcohol withdrawal
B. Lead poisoning
C. Schizophrenia
D. Cocaine abuse (Correct Answer)

Explanation: ### Explanation **Correct Option: D. Cocaine abuse** The sensation of insects crawling on or under the skin is known as **Formication**. When specifically associated with cocaine use, it is termed **"Cocaine Bugs"** or **Magnan’s sign**. This is a type of tactile hallucination (haptic hallucination). It occurs due to the stimulant effect of cocaine on the central nervous system, which can lead to sensory distortions and paranoid psychosis. Patients often present with "excoriation disorder" (skin picking) or "pocked" skin as they attempt to dig out the non-existent insects. **Analysis of Incorrect Options:** * **A. Alcohol withdrawal:** While alcohol withdrawal can cause tactile hallucinations (and more commonly visual hallucinations like *Lilliputian hallucinations*), formication is the classic hallmark of stimulant abuse (Cocaine/Amphetamines). * **B. Lead poisoning:** Lead toxicity typically presents with neurological symptoms like encephalopathy, peripheral neuropathy (wrist drop/foot drop), and abdominal colic, but not typically formication. * **C. Schizophrenia:** While tactile hallucinations can occur in schizophrenia, they are much less common than auditory hallucinations. Formication is more characteristically associated with organic/substance-induced states. **High-Yield Clinical Pearls for NEET-PG:** * **Magnan’s Sign:** Specifically refers to the tactile hallucination of crawling insects in chronic cocaine users. * **Tactile Hallucinations:** Also seen in **Ekbom’s Syndrome** (Delusional Parasitosis), where the patient has a fixed false belief of infestation. * **Formication vs. Lilliputian:** Formication is tactile (crawling insects); Lilliputian is visual (seeing tiny people/objects), often seen in Delirium Tremens. * **Other Stimulants:** Amphetamines and Methamphetamines can also cause similar formication ("Meth bugs").

Question 42: Which of the following medications is NOT used in the treatment of opioid withdrawal?

A. Disulfiram (Correct Answer)
B. Buprenorphine
C. Clonidine
D. Lofexidine

Explanation: **Explanation:** The correct answer is **Disulfiram**. **Why Disulfiram is the correct choice:** Disulfiram is an aldehyde dehydrogenase inhibitor used in the **aversion therapy of Alcohol Use Disorder**, not opioid withdrawal. It works by causing an accumulation of acetaldehyde if alcohol is consumed, leading to a highly unpleasant "disulfiram-like reaction" (flushing, tachycardia, nausea). It has no pharmacological role in managing opioid withdrawal symptoms. **Analysis of Incorrect Options:** * **Buprenorphine:** A partial mu-opioid agonist. It is a first-line agent for opioid withdrawal as it provides enough opioid effect to prevent withdrawal symptoms and cravings without producing a significant "high" due to its ceiling effect. * **Clonidine:** An alpha-2 adrenergic agonist. It is used off-label to manage the **autonomic hyperactivity** associated with opioid withdrawal (e.g., hypertension, tachycardia, sweating, and anxiety). * **Lofexidine:** Similar to clonidine, it is a selective alpha-2 adrenergic agonist. It is specifically FDA-approved for the mitigation of opioid withdrawal symptoms and often has a better side-effect profile (less hypotension) than clonidine. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard for Opioid Withdrawal:** Methadone (full agonist) or Buprenorphine (partial agonist). * **Objective Assessment:** The **COWS (Clinical Opiate Withdrawal Scale)** is used to monitor the severity of withdrawal. * **Naltrexone:** An opioid antagonist used for **relapse prevention** (maintenance), but it should *never* be given during active withdrawal as it will precipitate a severe withdrawal crisis. * **Pupillary Sign:** Opioid withdrawal causes **Mydriasis** (dilation), whereas acute intoxication causes **Miosis** (pinpoint pupils).

Question 43: All of the following are psychedelic drugs except?

A. Lysergic acid diethylamide
B. Phencyclidine
C. Cocaine (Correct Answer)
D. Mescaline

Explanation: **Explanation:** The question asks to identify the drug that is **not** a psychedelic. **1. Why Cocaine is the correct answer:** Cocaine is classified as a **Psychostimulant**, not a psychedelic. Its primary mechanism involves blocking the reuptake of monoamines (Dopamine, Norepinephrine, and Serotonin) in the synaptic cleft, leading to increased sympathetic activity. Clinically, it produces euphoria, increased alertness, and sympathomimetic effects (tachycardia, mydriasis), rather than the primary sensory distortions and "mind-manifesting" experiences characteristic of psychedelics. **2. Why the other options are incorrect:** * **Lysergic acid diethylamide (LSD):** The prototype **Serotonergic Hallucinogen**. It acts as a partial agonist at 5-HT2A receptors, causing profound alterations in perception, mood, and cognitive processes (e.g., synesthesia). * **Mescaline:** A naturally occurring psychedelic alkaloid derived from the **Peyote cactus**. Like LSD, it acts primarily on serotonin receptors to produce hallucinogenic effects. * **Phencyclidine (PCP):** Known as a **Dissociative Anesthetic/Hallucinogen**. It acts as an NMDA receptor antagonist. While its mechanism differs from LSD, it is traditionally categorized under the broad umbrella of psychedelic/hallucinogenic substances due to the detachment and sensory distortions it induces. **Clinical Pearls for NEET-PG:** * **Hallucinogen Persisting Perception Disorder (HPPD):** Re-experiencing perceptual symptoms ("flashbacks") long after stopping LSD. * **PCP Toxicity:** Look for **vertical/rotary nystagmus** and extreme agitation/belligerence in clinical vignettes. * **Cocaine Complication:** Formication (sensation of insects crawling under the skin, known as "Cocaine bugs"). * **Antidote:** There is no specific antidote for Cocaine; management is supportive (Benzodiazepines for agitation/seizures). Avoid Beta-blockers due to risk of unopposed alpha-stimulation.

Question 44: A person consumes large quantities of alcohol daily for 20 years and is physically dependent on alcohol. Which drug should be given to this person?

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

Explanation: **Explanation:** The correct answer is **Disulfiram**. This question focuses on the long-term management of alcohol dependence (sobriety maintenance) rather than acute withdrawal. **Why Disulfiram is correct:** Disulfiram is an **aldehyde dehydrogenase inhibitor**. When a patient on Disulfiram consumes alcohol, acetaldehyde accumulates in the body, leading to the **Disulfiram-Ethanol Reaction (DER)**. This causes highly unpleasant symptoms like flushing, tachycardia, nausea, and palpitations. It acts as **aversion therapy**, providing a psychological deterrent against drinking in a person who is physically dependent and motivated to quit. **Analysis of Incorrect Options:** * **Acamprosate (A):** An NMDA receptor antagonist used to maintain abstinence by reducing "protracted withdrawal" symptoms (insomnia, anxiety). It is preferred in patients with liver disease but is generally secondary to deterrents in classic "physical dependence" scenarios in exams. * **Naltrexone (C):** An opioid antagonist that reduces the "reward" or "craving" associated with alcohol by blocking endogenous opioid release. It is used to reduce heavy drinking but does not cause a physical reaction like Disulfiram. * **Chlordiazepoxide (D):** A long-acting benzodiazepine. It is the **drug of choice for acute alcohol withdrawal** to prevent seizures and delirium tremens, but it is not used for long-term maintenance of sobriety due to its own addictive potential. **High-Yield Clinical Pearls for NEET-PG:** * **Disulfiram** should never be administered until the patient has been abstinent for at least **12 hours**. * **Acamprosate** is the drug of choice for alcohol dependence in patients with **liver failure** (as it is renally excreted). * **Naltrexone** is the drug of choice for patients with **high cravings** or those who wish to reduce consumption rather than achieve total abstinence. * **Wernicke’s Encephalopathy:** Always remember to give Thiamine *before* Glucose in chronic alcoholics.

Question 45: Physical dependence is not seen with which of the following?

A. Alcohol
B. Raw opium
C. Raw opium (Correct Answer)
D. Benzodiazepines

Explanation: **Explanation:** The concept of **Physical Dependence** refers to a state where the body has adapted to the presence of a drug, manifesting as tolerance and a specific **withdrawal syndrome** upon cessation. **Why "Raw Opium" is the correct answer (in the context of this specific question):** In standard psychiatric classification and pharmacology, **Cannabis** (often confused with opium in older question banks) is the classic example of a substance where physical dependence is traditionally considered minimal or absent compared to others. However, looking at the options provided, there appears to be a typographical error in the question source where "Raw Opium" is marked correct. **Clinically and pharmacologically, Opium (an opioid) DOES cause profound physical dependence.** If the intended answer is indeed "Raw Opium," it is likely a legacy question referring to the fact that raw forms have lower potency than refined alkaloids (like Morphine/Heroin), or it is a distractor for **Cannabis/LSD/Cocaine**, which are the substances typically associated with a lack of significant physical dependence in NEET-PG patterns. **Analysis of Options:** * **Alcohol:** Causes severe physical dependence. Withdrawal can be life-threatening (Delirium Tremens, seizures). * **Benzodiazepines:** These act on GABA-A receptors and cause significant physical dependence; abrupt cessation leads to withdrawal symptoms similar to alcohol. * **Opium/Opioids:** These are the prototype for physical dependence, characterized by severe "flu-like" withdrawal symptoms (rhinorrhea, lacrimation, diarrhea, and body aches). **NEET-PG High-Yield Pearls:** 1. **No Physical Dependence:** LSD, Cocaine (primarily psychological), and Cannabis (minimal). 2. **Highest Physical Dependence:** Opioids and Alcohol. 3. **Withdrawal Seizures:** Most common with Alcohol and Benzodiazepines. 4. **Psychological Dependence:** Seen with almost all drugs of abuse, including Cocaine and Amphetamines.

Question 46: All are symptoms of opiate withdrawal except:

A. Diarrhea
B. Lacrimation
C. Mydriasis
D. Excessive speech (Correct Answer)

Explanation: **Explanation:** Opiate withdrawal is characterized by a "rebound" of the autonomic nervous system. Since opioids are central nervous system (CNS) depressants that cause constipation, miosis (pupillary constriction), and sedation, their withdrawal results in the polar opposite effects: **CNS hyperexcitability and autonomic hyperactivity.** **Why "Excessive Speech" is the correct answer:** Excessive speech (logorrhea) or pressured speech is a hallmark of **stimulant intoxication** (e.g., cocaine, amphetamines) or manic episodes. In opiate withdrawal, while the patient may be anxious or irritable, they do not typically exhibit the increased talkativeness associated with dopamine-driven stimulant use. **Analysis of Incorrect Options:** * **Diarrhea:** Opioids cause constipation by slowing GI motility. Withdrawal leads to intestinal hypermotility, resulting in abdominal cramps and diarrhea. * **Lacrimation:** This is a classic "wet" symptom of opiate withdrawal, alongside rhinorrhea (runny nose) and sweating (diaphoresis). * **Mydriasis:** While opioid intoxication causes "pinpoint pupils" (miosis), withdrawal causes pupillary dilation (mydriasis) due to sympathetic overactivity. **High-Yield Clinical Pearls for NEET-PG:** * **Objective Signs:** Look for **piloerection** (goosebumps), which gives rise to the term "cold turkey." * **Yawning:** A highly specific early sign of opioid withdrawal often tested in exams. * **Timeline:** Symptoms usually peak at 48–72 hours for heroin. * **Management:** Clonidine (alpha-2 agonist) is used to treat autonomic symptoms; Methadone or Buprenorphine is used for detoxification/maintenance. * **Crucial Fact:** Unlike alcohol or benzodiazepine withdrawal, pure opioid withdrawal is extremely uncomfortable but **rarely life-threatening.**

Question 47: Methadone is used in the treatment of overdose of which of the following substances?

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

Explanation: **Explanation:** The correct answer is **Heroin**. **Why Heroin is Correct:** Methadone is a **long-acting synthetic opioid agonist** that binds to the $\mu$-opioid receptors. In the context of opioid use disorder (specifically Heroin), Methadone is used for **Maintenance Therapy** and detoxification. It works by preventing withdrawal symptoms and reducing "craving" without producing the intense euphoria associated with shorter-acting opioids like heroin. This is due to its long half-life (24–36 hours) and slow onset of action. *Note on the Question Wording:* While the question uses the term "overdose," clinically, Methadone is the gold standard for **Opioid Substitution Therapy (OST)**. For acute life-threatening respiratory depression in an opioid overdose, the drug of choice is **Naloxone** (an antagonist). **Why Other Options are Incorrect:** * **Cocaine & Amphetamines:** These are CNS stimulants. There is no specific pharmacological replacement therapy like methadone for stimulants; management is primarily supportive (e.g., benzodiazepines for agitation). * **Barbiturates:** These are sedative-hypnotics. Overdose is managed with supportive care (airway protection) and alkalization of urine (for phenobarbital). There is no role for methadone here. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice for Acute Opioid Overdose:** Naloxone (IV/Intranasal). * **Drug of Choice for Opioid Withdrawal in Pregnancy:** Methadone. * **Buprenorphine:** A partial $\mu$-agonist and $\kappa$-antagonist; also used for maintenance but has a "ceiling effect" on respiratory depression, making it safer than methadone. * **Naltrexone:** An oral opioid antagonist used for relapse prevention *after* detoxification is complete.

Question 48: All of the following effects are seen with cocaine except?

A. Black pigmentation of the tongue
B. Nasal septal perforation
C. Freebasing
D. Sympatholytic effect (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. Sympatholytic effect**. Cocaine is a potent **indirect-acting sympathomimetic** agent. It works by blocking the reuptake of catecholamines (dopamine, norepinephrine, and serotonin) at the synaptic cleft. This leads to an excess of norepinephrine, causing a "sympathomimetic toxidrome" characterized by tachycardia, hypertension, mydriasis, and diaphoresis. Therefore, it has a **sympathomimetic** effect, not a sympatholytic (blocking) one. **Analysis of other options:** * **A. Black pigmentation of the tongue:** Chronic cocaine smokers may develop a characteristic black coating on the dorsum of the tongue, often referred to as "cocaine tongue," likely due to the direct effects of the smoke or contaminants. * **B. Nasal septal perforation:** Cocaine is a powerful vasoconstrictor. When snorted (insufflation), it causes intense local ischemia in the nasal mucosa. Chronic use leads to necrosis of the cartilaginous septum, resulting in perforation. * **C. Freebasing:** This refers to the process of converting cocaine hydrochloride (powder) into a purified, smokable "freebase" form (like crack cocaine) to achieve a more rapid and intense high. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Inhibits reuptake of biogenic amines (Dopamine > NE > 5-HT). * **Cardiac Risk:** Cocaine-induced vasospasm can lead to Myocardial Infarction. **Beta-blockers are contraindicated** in management due to the risk of unopposed alpha-adrenergic stimulation. * **Formication:** A tactile hallucination known as "Cocaine bugs" (Magnan’s sign) where the patient feels insects crawling under the skin. * **Pupils:** Causes **Mydriasis** (dilated pupils), unlike opioids which cause Miosis.

Question 49: In delirium tremens, all are true, except:

A. Gross tremor
B. Seen in alcoholic withdrawal
C. Seizures may occur
D. Orientation is clear (Correct Answer)

Explanation: **Explanation:** **Delirium Tremens (DT)** is the most severe form of alcohol withdrawal, typically occurring 48–96 hours after the last drink. It is a medical emergency characterized by a "clouding of consciousness." 1. **Why Option D is the Correct Answer:** In Delirium Tremens, **disorientation** (to time, place, and person) is a hallmark feature. The term "Delirium" itself implies an acute organic brain syndrome characterized by global cognitive impairment and a fluctuating level of consciousness. Therefore, the statement "Orientation is clear" is false. 2. **Analysis of Other Options:** * **Option A (Gross tremor):** DT is characterized by intense autonomic hyperactivity. Coarse, gross tremors of the hands and trunk are classic physical findings. * **Option B (Seen in alcoholic withdrawal):** DT is specifically a withdrawal phenomenon, occurring in individuals with a long history of heavy alcohol consumption who suddenly stop or reduce intake. * **Option C (Seizures may occur):** While "Rum Fits" (withdrawal seizures) usually occur within 6–48 hours, they can precede or occur during the onset of DT. **High-Yield Clinical Pearls for NEET-PG:** * **Timeline:** 6–12 hrs (Tremors) → 12–24 hrs (Hallucinosis) → 6–48 hrs (Seizures) → 48–96 hrs (Delirium Tremens). * **Hallucinations:** Most commonly **Visual** (e.g., Lilliputian hallucinations) or Tactile (Formication/Cocaine bugs). * **Treatment:** **Benzodiazepines** (Chlordiazepoxide or Diazepam) are the drug of choice. In patients with liver failure, use **LOT** (Lorazepam, Oxazepam, Temazepam). * **Mortality:** If untreated, mortality can be as high as 20% due to cardiovascular collapse or hyperthermia.

Question 50: In an alcoholic man, what is a 'blackout' seen in?

A. Alcohol abstinence
B. Hepatic encephalopathy
C. Alcohol intoxication (Correct Answer)
D. Alcohol withdrawal

Explanation: **Explanation:** An **alcohol blackout** is a period of anterograde amnesia that occurs during a bout of heavy drinking. It is characterized by the inability to form new long-term memories while the individual remains conscious and capable of performing complex tasks (e.g., talking, driving). **1. Why Alcohol Intoxication is Correct:** Blackouts occur during **acute alcohol intoxication** when blood alcohol levels rise rapidly. The underlying mechanism involves the inhibition of the **hippocampus**, specifically the suppression of long-term potentiation (LTP) via NMDA receptor antagonism and GABA-A receptor enhancement. This prevents the transfer of information from short-term to long-term memory. **2. Why Other Options are Incorrect:** * **Alcohol Abstinence & Withdrawal:** These states occur when a dependent person stops drinking. Symptoms include tremors, seizures, and delirium tremens. Blackouts are a phenomenon of *active consumption*, not cessation. * **Hepatic Encephalopathy:** This is a neuropsychiatric complication of liver failure caused by ammonia toxicity. While it causes altered consciousness and confusion, it is a metabolic derangement rather than the specific amnestic "gap" defined as a blackout. **Clinical Pearls for NEET-PG:** * **Types of Blackouts:** * *En bloc:* Total permanent amnesia for a period. * *Fragmentary (Brownout):* Partial memory loss where cues can trigger recall. * **Jellinek’s Phases:** In Jellinek’s typology of alcoholism, blackouts are considered a hallmark of the **Prodromal Phase**. * **Wernicke-Korsakoff Syndrome:** Do not confuse blackouts with Korsakoff psychosis. Blackouts are transient amnestic episodes during intoxication, whereas Korsakoff is a chronic, irreversible amnestic disorder due to Thiamine (B1) deficiency.

Practice by Chapter

Neurobiology of Addiction

Practice Questions

Alcohol Use Disorder

Practice Questions

Opioid Use Disorder

Practice Questions

Cannabis Use Disorder

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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

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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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