Substance Use Disorders — MCQs

Substance Use Disorders Indian Medical PG Practice Questions and MCQs

Question 201: What is the detoxification treatment for alcohol intoxication?

A. Benzodiazepines for 7-14 days (Correct Answer)
B. Barbiturates for 10 days
C. Benzodiazepines for 1 month
D. Benzodiazepines for 2 days

Explanation: **Explanation:** The primary goal of alcohol detoxification is to manage withdrawal symptoms and prevent life-threatening complications like **Delirium Tremens** and **Wernicke’s Encephalopathy**. **1. Why Option A is Correct:** Benzodiazepines (BZDs) are the gold standard for alcohol detoxification because they show **cross-tolerance** with alcohol. Both substances act as GABA-A receptor agonists. When alcohol is withdrawn, BZDs substitute for its effect, preventing neuronal hyperexcitability. The standard detoxification protocol typically lasts **7 to 14 days**, allowing for a gradual tapering of the dose to prevent rebound withdrawal while ensuring the patient is safely past the peak window of seizure risk (usually 24–48 hours) and delirium (72–96 hours). **2. Why Other Options are Incorrect:** * **Option B:** While barbiturates have been used historically, they have a narrower therapeutic index and a higher risk of respiratory depression compared to BZDs. * **Option C:** One month is unnecessarily long for acute detoxification. Prolonged use increases the risk of dependence and cognitive impairment. * **Option D:** Two days is insufficient. Alcohol withdrawal symptoms can peak at 72 hours and persist for up to a week; stopping treatment too early increases the risk of withdrawal seizures and Delirium Tremens. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice (DOC):** Long-acting BZDs like **Chlordiazepoxide** or **Diazepam** are preferred due to smoother tapering. * **Liver Disease Exception:** In patients with liver cirrhosis or elderly patients, use **LOT** (Lorazepam, Oxazepam, Temazepam) as they do not have active metabolites and are not dependent on hepatic oxidation. * **Wernicke’s Prophylaxis:** Always administer **Thiamine (Vitamin B1)** before glucose to prevent precipitating Wernicke’s Encephalopathy.

Question 202: In delirium tremens, all the following are true, except?

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

Explanation: **Explanation:** Delirium Tremens (DT) is the most severe form of alcohol withdrawal, occurring typically 48–96 hours after the last drink. It is a medical emergency characterized by a **clouding of consciousness**. **Why "Orientation clear" is the correct answer (the exception):** By definition, delirium involves an acute disturbance in attention and awareness. In DT, patients experience profound **disorientation** to time, place, and person. Therefore, "Orientation clear" is false. **Analysis of other options:** * **Gross tremor (A):** Autonomic hyperactivity is a hallmark of DT. Patients exhibit coarse, rhythmic tremors of the hands, tongue, or eyelids, often accompanied by tachycardia, sweating, and hypertension. * **Seen in alcoholic withdrawal (B):** DT is specifically a withdrawal phenomenon occurring in individuals with long-term, heavy alcohol dependence when they abruptly stop or significantly reduce intake. * **Fits may occur (C):** Alcohol withdrawal seizures (rum fits) typically occur 6–48 hours after cessation. While they usually precede DT, they can occur concurrently or as part of the evolving withdrawal syndrome. **Clinical Pearls for NEET-PG:** * **Hallucinations:** In DT, these are most commonly **visual** (e.g., seeing small animals or insects—microzoopsia) or tactile (formication), rather than auditory. * **Mortality:** Without treatment, the mortality rate is up to 20% (usually due to hyperthermia, arrhythmias, or cardiovascular collapse). * **Drug of Choice:** **Benzodiazepines** (e.g., Diazepam, Lorazepam) are the gold standard for management. * **Wernicke’s Prevention:** Always administer **Thiamine** before Glucose to prevent precipitating Wernicke’s Encephalopathy.

Question 203: Which of the following drugs has no potential for dependence or addiction?

A. Morphine
B. Amphetamines
C. Benzodiazepines
D. LSD (Correct Answer)

Explanation: **Explanation:** The correct answer is **LSD (Lysergic acid diethylamide)**. **1. Why LSD is the correct answer:** LSD is a potent psychedelic (hallucinogen) that acts primarily as a partial agonist at **5-HT2A receptors**. Unlike most drugs of abuse, LSD does **not** stimulate the release of dopamine in the mesolimbic "reward" pathway (the nucleus accumbens). Because it does not trigger this dopaminergic reward mechanism, it does not cause cravings, compulsive drug-seeking behavior, or physical dependence. While users develop rapid **tachyphylaxis** (tolerance), there is no recognized withdrawal syndrome or addiction potential. **2. Why the other options are incorrect:** * **Morphine:** An opioid agonist that causes profound euphoria and physical dependence. Withdrawal is characterized by lacrimation, rhinorrhea, and "gooseflesh" (piloerection). * **Amphetamines:** These increase synaptic dopamine by stimulating release and inhibiting reuptake. They have a very high potential for psychological addiction and can induce a "schizophrenia-like" stimulant psychosis. * **Benzodiazepines:** These act on GABA-A receptors. Chronic use leads to down-regulation of receptors, resulting in physical dependence and a potentially life-threatening withdrawal syndrome (seizures and delirium). **High-Yield Clinical Pearls for NEET-PG:** * **Hallucinogen Persisting Perception Disorder (HPPD):** A unique long-term complication of LSD where "flashbacks" occur long after the drug has cleared. * **Bad Trip Management:** The first-line treatment for acute LSD intoxication/panic is reassurance ("talking down") and Benzodiazepines if necessary. * **Tolerance:** LSD shows **cross-tolerance** with other hallucinogens like Psilocybin and Mescaline.

Question 204: Which of the following structures is not involved in Wernicke's-Korsakoff syndrome?

A. Mamillary body
B. Thalamus
C. Periventricular grey matter
D. Hippocampus (Correct Answer)

Explanation: **Explanation:** **Wernicke-Korsakoff Syndrome (WKS)** is a neurological complication of chronic thiamine (Vitamin B1) deficiency, most commonly seen in alcohol use disorder. The pathophysiology involves biochemical lesions in brain regions with high metabolic demands and high thiamine turnover. **Why Hippocampus is the correct answer:** While the hippocampus is vital for memory consolidation, it is **not** a primary site of the characteristic hemorrhagic or necrotic lesions seen in WKS. The memory deficits in Korsakoff syndrome (anterograde and retrograde amnesia) are primarily due to damage in the **diencephalon** (thalamus and mammillary bodies) rather than the temporal lobe structures like the hippocampus. **Why other options are incorrect:** * **Mamillary Bodies (A):** Atrophy of the mammillary bodies is the **hallmark** pathological finding of WKS. It is present in nearly all chronic cases and is highly specific. * **Thalamus (B):** Specifically, the **dorsomedial nucleus** and anterior nuclei of the thalamus are frequently involved. Damage here is responsible for the profound amnesia and confabulation seen in Korsakoff psychosis. * **Periventricular Grey Matter (C):** Lesions are commonly found in the periaqueductal and periventricular grey matter (around the 3rd and 4th ventricles), which correlates with the ocular signs (ophthalmoplegia) and ataxia. **High-Yield Clinical Pearls for NEET-PG:** 1. **Wernicke’s Encephalopathy (Acute):** Triad of **C**onfusion, **A**taxia, and **N**ystagmus/Ophthalmoplegia (**CAN**). It is a medical emergency. 2. **Korsakoff Psychosis (Chronic):** Characterized by profound amnesia and **confabulation** (filling memory gaps with imaginary stories). 3. **Treatment Rule:** Always administer **Thiamine before Glucose**. Giving IV glucose first can precipitate or worsen WKS by consuming the remaining thiamine stores during glycolysis. 4. **Imaging:** MRI may show hyperintensities in the mammillary bodies and periaqueductal grey.

Question 205: All of the following are criteria for substance dependence except?

A. Recurrent substance-related legal problems
B. Characteristic withdrawal symptoms; substance taken to relieve withdrawal (Correct Answer)
C. Substance taken in larger amounts and for longer than intended
D. Recurrent unsuccessful attempts to quit the substance

Explanation: This question tests your ability to distinguish between **Substance Dependence** and **Substance Abuse** based on the **DSM-IV** criteria. While the current DSM-5 combines these into "Substance Use Disorder," NEET-PG frequently tests the classic DSM-IV distinctions. ### **Explanation of the Correct Answer** **Option A (Recurrent substance-related legal problems)** is the correct answer because it is a criterion for **Substance Abuse**, not Substance Dependence. Under DSM-IV, Substance Abuse is characterized by a maladaptive pattern leading to clinically significant impairment, involving: 1. Failure to fulfill major role obligations (work/school). 2. Use in physically hazardous situations (e.g., driving). 3. **Legal problems.** 4. Continued use despite social/interpersonal problems. ### **Analysis of Incorrect Options (Criteria for Dependence)** Options B, C, and D are all core components of the **7 criteria for Substance Dependence** (where at least 3 must be present within a 12-month period): * **Option B (Withdrawal):** Physical symptoms occur when the substance is stopped, or the substance is taken to avoid these symptoms. * **Option C (Loss of Control):** Using larger amounts or for longer periods than originally intended. * **Option D (Desire to Cut Down):** Persistent desire or unsuccessful efforts to curtail use. ### **High-Yield Clinical Pearls for NEET-PG** * **Tolerance:** The need for markedly increased amounts of the substance to achieve intoxication or a diminished effect with the same amount. * **Salience:** Giving up important social, occupational, or recreational activities because of substance use. * **DSM-5 Update:** In DSM-5, "Legal problems" was **removed** as a criterion, and "Craving" was **added**. * **ICD-10:** Uses the term "Dependence Syndrome" (requires 3 or more of 6 criteria).

Question 206: Which drug is used to prevent alcohol withdrawal symptoms?

A. Diazepam (Correct Answer)
B. Clonidine
C. Propranolol
D. Methadone

Explanation: **Explanation:** The correct answer is **Diazepam**. **Why Diazepam is correct:** Alcohol is a central nervous system (CNS) depressant that enhances GABAergic tone. Chronic use leads to the downregulation of GABA receptors. Abrupt cessation causes a "hyperexcitable" state due to GABA deficiency and NMDA overactivity. **Benzodiazepines (BZDs)**, like Diazepam, are the **gold standard** for preventing and treating alcohol withdrawal. They act as cross-tolerant agents that substitute for alcohol at the GABA-A receptor, effectively tapering the CNS excitability, preventing seizures, and reducing the risk of Delirium Tremens. **Analysis of Incorrect Options:** * **Clonidine (B):** An alpha-2 agonist that helps manage autonomic hyperactivity (tachycardia, hypertension) but **does not** prevent seizures or delirium. * **Propranolol (C):** A beta-blocker used to reduce tremors and palpitations. Like clonidine, it masks symptoms but does not treat the underlying neurochemical imbalance or prevent life-threatening complications. * **Methadone (D):** A long-acting opioid agonist used specifically for **Opioid Use Disorder** (maintenance and detoxification), not alcohol withdrawal. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice (DOC):** Long-acting BZDs like **Diazepam** or **Chlordiazepoxide** are preferred due to their self-tapering effect. * **Liver Disease Exception:** In patients with liver failure or the elderly, use **LOT** (Lorazepam, Oxazepam, Temazepam) because they do not have active metabolites and undergo direct glucuronidation. * **Wernicke’s Prophylaxis:** Always administer **Thiamine (B1)** before glucose to prevent precipitating Wernicke’s Encephalopathy.

Question 207: Paranoid psychosis associated with cocaine use is primarily due to which of the following phenomena?

A. Tolerance
B. Withdrawal
C. Reverse Tolerance
D. Intoxication (Correct Answer)

Explanation: **Explanation:** **1. Why Intoxication is Correct:** Cocaine is a potent sympathomimetic that acts by blocking the reuptake of dopamine, norepinephrine, and serotonin. Paranoid psychosis (often called "cocaine psychosis") is a direct manifestation of **acute intoxication**. The rapid increase in synaptic dopamine levels—particularly in the mesolimbic pathway—mimics the pathophysiology of schizophrenia, leading to symptoms such as persecutory delusions, tactile hallucinations (formication/cocaine bugs), and extreme agitation. **2. Why Other Options are Incorrect:** * **Tolerance (A):** This refers to the need for higher doses to achieve the same effect. While cocaine users develop rapid tolerance to the euphoric "high," tolerance itself does not trigger psychosis. * **Withdrawal (B):** Cocaine withdrawal (the "crash") is characterized by dysphoria, hypersomnia, hyperphagia, and psychomotor retardation. It is a "low-energy" state, whereas psychosis is a "high-energy" state associated with active use. * **Reverse Tolerance (C):** Also known as *sensitization*, this refers to an increased response to the same dose of a drug over time. While sensitization may lower the threshold for future psychotic episodes, the clinical presentation of paranoid psychosis occurs during the state of **intoxication**. **3. NEET-PG High-Yield Clinical Pearls:** * **Formication (Magnan’s Sign):** The specific tactile hallucination of insects crawling under the skin is a classic sign of cocaine intoxication. * **Pupillary Findings:** Cocaine causes **Mydriasis** (dilated pupils), distinguishing it from opioid intoxication (miosis). * **Vital Signs:** Look for tachycardia, hypertension, and hyperthermia in clinical vignettes. * **Treatment:** Benzodiazepines are the first-line treatment for cocaine-induced agitation and psychosis; Beta-blockers should be avoided due to the risk of unopposed alpha-adrenergic stimulation.

Question 208: Which of the following antiepileptic drugs can be used in the management of alcohol withdrawal symptoms?

A. Phenytoin
B. Carbamazepine (Correct Answer)
C. Valproate
D. Topiramate

Explanation: **Explanation:** The management of alcohol withdrawal focuses on counteracting the CNS hyperexcitability caused by the sudden cessation of alcohol’s GABAergic effects and the compensatory overactivity of NMDA receptors. **Why Carbamazepine is Correct:** **Carbamazepine** is a well-established non-benzodiazepine alternative for managing **mild to moderate alcohol withdrawal**. It acts by stabilizing neuronal membranes and reducing glutamate-mediated excitability. Its primary advantages include: * **No abuse potential:** Unlike benzodiazepines, it does not cause sedation or respiratory depression. * **Anti-kindling effect:** It prevents the "kindling" phenomenon (where repeated withdrawal episodes become progressively more severe). * **Superiority in preventing post-withdrawal seizures:** It is specifically effective in reducing the risk of withdrawal-related seizures compared to other anticonvulsants. **Why the other options are incorrect:** * **Phenytoin (A):** It is notoriously **ineffective** in preventing or treating alcohol withdrawal seizures. Withdrawal seizures are caused by neurotransmitter imbalances, not a focal epileptic focus, which is where phenytoin acts. * **Valproate (C):** While it has some efficacy in withdrawal, it is generally avoided due to potential **hepatotoxicity**, which is a significant concern in chronic alcohol users who may already have alcoholic liver disease. * **Topiramate (D):** It is primarily used in the **maintenance of abstinence** (reducing cravings and heavy drinking days) rather than the acute management of withdrawal symptoms. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard:** Benzodiazepines (e.g., Chlordiazepoxide, Diazepam) remain the first-line treatment for alcohol withdrawal. * **Liver Disease:** If the patient has cirrhosis or liver failure, use **LOT** (Lorazepam, Oxazepam, Temazepam) as they undergo extrahepatic metabolism. * **Wernicke’s Prevention:** Always administer **Thiamine** before Glucose to prevent Wernicke’s Encephalopathy. * **Carbamazepine Side Effect:** Monitor for Stevens-Johnson Syndrome (SJS) and agranulocytosis.

Question 209: A 45-year-old chronic alcoholic presents with confusion, ataxia, ophthalmoplegia, and peripheral neuropathy. What is the most likely diagnosis?

A. Korsakoff's psychosis
B. Delirium tremens
C. Alcoholic hallucinosis
D. Wernicke's encephalopathy (Correct Answer)

Explanation: **Explanation:** The patient presents with the classic **clinical triad** of **Wernicke’s Encephalopathy (WE)**: 1. **Ophthalmoplegia** (specifically nystagmus or abducens nerve palsy) 2. **Ataxia** (gait instability) 3. **Confusion** (Global encephalopathy) **Underlying Concept:** WE is an acute, reversible biochemical lesion caused by a deficiency of **Thiamine (Vitamin B1)**. In chronic alcoholics, this deficiency arises due to poor dietary intake, impaired gastrointestinal absorption, and reduced hepatic storage. Thiamine is a co-factor for key enzymes in glucose metabolism; its absence leads to neuronal cell death, particularly in the **mammillary bodies** and the periaqueductal gray matter. **Why other options are incorrect:** * **Korsakoff’s Psychosis:** This is the chronic, often irreversible stage following WE. It is characterized by **anterograde amnesia** and **confabulation** (filling memory gaps with fabrications). While often occurring together (Wernicke-Korsakoff Syndrome), the acute triad points to WE. * **Delirium Tremens:** A severe form of alcohol withdrawal occurring 48–96 hours after the last drink. It features autonomic hyperactivity (tachycardia, hypertension), tremors, and clouded consciousness, but not ophthalmoplegia. * **Alcoholic Hallucinosis:** Occurs within 12–24 hours of abstinence. It is characterized by vivid auditory hallucinations in a state of **clear sensorium** (the patient is alert and oriented), unlike the confusion seen here. **High-Yield NEET-PG Pearls:** * **MRI Finding:** Increased T2/FLAIR signal intensity in the **mammillary bodies** (most specific) and dorsomedial thalamus. * **Management:** Immediate administration of **IV Thiamine**. * **Crucial Rule:** Always give Thiamine **before** Glucose. Administering glucose first in a thiamine-deficient patient can precipitate or worsen WE by consuming the remaining thiamine stores during glycolysis.

Question 210: Paranoid psychosis observed with cocaine abuse can be explained by?

A. Tolerance
B. Intoxication
C. Reverse tolerance (Correct Answer)
D. Withdrawal

Explanation: **Explanation:** The correct answer is **Reverse tolerance (Sensitization)**. **1. Why Reverse Tolerance is Correct:** Reverse tolerance, also known as **behavioral sensitization**, refers to a phenomenon where a lower dose of a substance produces the same or even more intense effects than previously experienced with higher doses. In cocaine abuse, repeated administration leads to an increased sensitivity of the dopaminergic pathways in the mesolimbic and nigrostriatal systems. This progressive sensitization is the underlying mechanism for the development of **cocaine-induced paranoid psychosis** (e.g., delusions of persecution, "cocaine bugs" or Formication). Unlike most effects of drugs which diminish with use, the psychotomimetic effects of cocaine often intensify. **2. Why Incorrect Options are Wrong:** * **Tolerance:** This refers to the need for increasing doses to achieve the same effect. While users develop tolerance to the euphoric "high" of cocaine, they develop *reverse tolerance* to its psychotic and motor effects. * **Intoxication:** While psychosis occurs during intoxication, the *explanation* for why it develops or worsens over chronic use is the physiological process of reverse tolerance. * **Withdrawal:** Cocaine withdrawal (the "crash") typically presents with dysphoria, hypersomnia, and increased appetite (the "triple A": Anhedonia, Appetite increase, Anergy), rather than active paranoid psychosis. **Clinical Pearls for NEET-PG:** * **Formication (Magnan’s Sign):** The tactile hallucination of insects crawling under the skin; a classic sign of cocaine psychosis. * **Mechanism:** Cocaine blocks the reuptake of Dopamine, Norepinephrine, and Serotonin. * **Kindling Effect:** Reverse tolerance is often compared to "kindling," where repeated sub-threshold stimuli eventually trigger a full psychotic or seizure response.

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

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Substance Withdrawal Syndromes

Practice Questions

Pharmacotherapy for Substance Use Disorders

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Psychosocial Interventions

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Dual Diagnosis Management

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