Substance Use Disorders — MCQs

Substance Use Disorders Indian Medical PG Practice Questions and MCQs

Question 191: Which of the following is a paraphilia?

A. Fetishism
B. Sadism
C. Masochism
D. All the above (Correct Answer)

Explanation: **Explanation:** Paraphilias are defined as intense and persistent sexual interests other than sexual interest in genital stimulation or preparatory fondling with phenotypically normal, physically mature, consenting human partners. According to the **DSM-5** and **ICD-11**, these disorders involve recurrent, intense sexual fantasies, urges, or behaviors that cause clinically significant distress or impairment. **Why "All the above" is correct:** * **Fetishism (Option A):** Involves the use of non-living objects (e.g., shoes, stockings) or a highly specific focus on non-genital body parts to achieve sexual arousal. * **Sexual Sadism (Option B):** Involves deriving sexual excitement from the physical or psychological suffering (including humiliation) of another person. * **Sexual Masochism (Option C):** Involves sexual arousal from the act of being humiliated, beaten, bound, or otherwise made to suffer. Since all three conditions are classic examples of paraphilic disorders, **Option D** is the correct choice. **High-Yield Clinical Pearls for NEET-PG:** * **Gender Distribution:** Paraphilias are almost exclusively diagnosed in **males**. * **Duration Criteria:** For a formal diagnosis under DSM-5, these interests must be present for at least **6 months**. * **Distinction:** A "Paraphilia" is the sexual interest itself, while a **"Paraphilic Disorder"** is a paraphilia that causes distress/impairment to the individual or involves non-consenting victims. * **Treatment:** The mainstay of pharmacological treatment for severe cases (to reduce libido) includes **Anti-androgens** (e.g., Cyproterone acetate) or **GnRH agonists** (e.g., Leuprolide). Cognitive Behavioral Therapy (CBT) is the preferred psychological intervention. * **Other common paraphilias:** Exhibitionism (exposure of genitals), Voyeurism (observing unsuspecting persons), and Frotteurism (touching/rubbing against non-consenting persons).

Question 192: What is the most severe manifestation of alcohol withdrawal syndrome?

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

Explanation: **Explanation:** **Delirium Tremens (DT)** is the most severe and life-threatening manifestation of alcohol withdrawal, occurring in approximately 5% of patients, usually **48 to 96 hours** after the last drink. It is a medical emergency characterized by a "clouding of consciousness" (delirium) and severe autonomic hyperactivity (tachycardia, hypertension, fever, and diaphoresis). The underlying pathophysiology involves a profound neurochemical rebound due to the sudden removal of alcohol's inhibitory effect on GABA receptors and the compensatory overactivity of NMDA (glutamate) receptors. Untreated DT has a mortality rate of up to 20%, primarily due to cardiovascular collapse or hyperthermia. **Analysis of Incorrect Options:** * **Wernicke's Encephalopathy (A):** This is a neurological complication of chronic alcohol use due to **Thiamine (B1) deficiency**, not a manifestation of the withdrawal syndrome itself. * **Seizures (C):** Also known as "rum fits," these typically occur early (**6–48 hours**) after cessation. While serious, they are usually self-limiting and less life-threatening than the systemic collapse seen in DT. * **Alcoholic Hallucinosis (D):** This involves vivid auditory or visual hallucinations with a **clear sensorium** (the patient is alert and oriented). It occurs within 12–24 hours and lacks the autonomic instability and delirium that define the severity of DT. **High-Yield Clinical Pearls for NEET-PG:** * **Timeline:** Tremors (6-12h) → Seizures (6-48h) → Hallucinosis (12-24h) → DT (48-96h). * **Drug of Choice:** Benzodiazepines (e.g., Diazepam, Lorazepam) are the gold standard for managing withdrawal. * **Prophylaxis:** Chlordiazepoxide is commonly used for detoxification. * **Distinction:** The hallmark of DT is **altered sensorium + autonomic instability**, whereas Hallucinosis has a **clear sensorium**.

Question 193: Which of the following drugs is known as Angel Dust?

A. Cannabis
B. Cocaine
C. Ecstasy
D. Phencyclidine (PCP) (Correct Answer)

Explanation: **Explanation:** **Phencyclidine (PCP)**, commonly known as **"Angel Dust,"** is a dissociative anesthetic that acts primarily as a non-competitive antagonist at the **NMDA (N-methyl-D-aspartate) receptor**. It was originally developed as an anesthetic but was discontinued due to severe adverse effects, including postoperative delirium and hallucinations. **Why the other options are incorrect:** * **Cannabis:** Commonly known as Marijuana, Weed, or Pot. Its psychoactive component is Delta-9-THC. * **Cocaine:** Known as Coke, Snow, or Crack. It is a potent stimulant that inhibits the reuptake of dopamine, norepinephrine, and serotonin. * **Ecstasy (MDMA):** Also known as "Molly" or "Adam." It is a substituted amphetamine with both stimulant and hallucinogenic properties, primarily affecting serotonin levels. **Clinical Pearls for NEET-PG:** 1. **Classic Presentation:** A patient presenting with **vertical or horizontal nystagmus**, extreme agitation, and **decreased pain perception** (analgesia) is highly suggestive of PCP toxicity. 2. **Psychiatric Symptoms:** PCP can induce a state indistinguishable from schizophrenia, including paranoia and violent behavior. 3. **Management:** The primary treatment for PCP-induced agitation is **Benzodiazepines** (e.g., Diazepam). Acidification of urine is no longer routinely recommended due to the risk of metabolic acidosis. 4. **Ketamine Connection:** Ketamine is a structural analog of PCP but is less potent and has a shorter duration of action.

Question 194: A 48-year-old male presents to the ER with confusion and shaking of the entire body. He has a history of alcoholism. What is the most likely cause of delirium tremens in an alcoholic patient?

A. Small consumption of alcohol
B. Gradual withdrawal from alcohol
C. Fatty liver
D. Acute infection (Correct Answer)

Explanation: **Explanation:** **Delirium Tremens (DTs)** is the most severe form of alcohol withdrawal, typically occurring 48–96 hours after the last drink. While the primary trigger is the cessation of alcohol, in clinical practice and NEET-PG scenarios, the development of full-blown DTs is often precipitated by a **secondary metabolic or physiological stressor.** **Why Acute Infection is the Correct Answer:** In a chronic alcoholic, the body exists in a state of neuroadaptation (downregulation of GABA receptors and upregulation of NMDA receptors). While withdrawal starts the process, **acute infections** (like pneumonia or UTI), trauma, or post-operative stress act as "precipitating factors" that tip the patient from simple withdrawal into Delirium Tremens. Infection increases metabolic demand and worsens the neurochemical imbalance, making it the most likely clinical trigger among the choices provided. **Analysis of Incorrect Options:** * **A. Small consumption of alcohol:** Alcohol consumption would actually suppress withdrawal symptoms, not cause DTs. * **B. Gradual withdrawal:** DTs occur due to **abrupt** cessation or a significant reduction in heavy, long-term use. Gradual tapering is a management strategy to *prevent* DTs. * **C. Fatty liver:** While common in alcoholics, hepatic steatosis itself does not trigger delirium. However, advanced cirrhosis leading to hepatic encephalopathy is a differential diagnosis for confusion. **High-Yield Clinical Pearls for NEET-PG:** * **Timeframe:** DTs occur 2–4 days after the last drink. * **Key Features:** Clouding of consciousness (delirium), autonomic hyperactivity (tachycardia, hypertension, fever), and vivid hallucinations (often visual/tactile). * **Drug of Choice:** **Benzodiazepines** (e.g., Diazepam, Lorazepam). Chlordiazepoxide is preferred for prevention. * **Mortality:** If untreated, the mortality rate is approximately 5–15%, often due to cardiovascular collapse or hyperthermia.

Question 195: What is the recommended loading dose of diazepam for managing alcohol withdrawal?

A. 20-30 mg
B. 25-85 mg
C. 60-150 mg (Correct Answer)
D. 200-300 mg

Explanation: **Explanation:** Alcohol withdrawal management focuses on preventing severe complications like seizures and delirium tremens. The **Loading Dose Strategy** (also known as front-loading) involves administering long-acting benzodiazepines to achieve rapid sedation and then allowing the drug’s long half-life to provide a "self-tapering" effect. **Why C is Correct:** For moderate to severe alcohol withdrawal, **Diazepam** is the drug of choice due to its rapid onset and long-acting metabolites. The standard recommended loading dose is **60–150 mg**. Typically, 10–20 mg is administered every 1–2 hours until the patient is adequately sedated (using scales like CIWA-Ar). This high cumulative dose is necessary to counteract the profound NMDA receptor upregulation and GABA-A receptor downregulation seen in chronic alcohol use. **Why Other Options are Incorrect:** * **A & B (20-30 mg / 25-85 mg):** These doses are generally insufficient for a true "loading" protocol in severe withdrawal. While 20-30 mg might suffice for mild anxiety, it fails to provide the seizure prophylaxis required in high-risk patients. * **D (200-300 mg):** These doses are excessively high and significantly increase the risk of over-sedation and respiratory depression, even in patients with high tolerance. **High-Yield NEET-PG Pearls:** * **Drug of Choice (General):** Chlordiazepoxide or Diazepam (long-acting). * **Drug of Choice (Liver Failure/Elderly):** **LOT** (Lorazepam, Oxazepam, Temazepam) because they undergo direct glucuronidation and do not have active metabolites. * **Wernicke’s Encephalopathy:** Always give **Thiamine before Glucose** to prevent precipitating acute Wernicke’s. * **Delirium Tremens:** Occurs 48–96 hours after the last drink; characterized by autonomic instability and clouded consciousness.

Question 196: Which of the following drugs is NOT used in alcohol dependence to prevent relapse?

A. Fluoxetine (Correct Answer)
B. Nalmefene
C. Acamprosate
D. Topiramate

Explanation: **Explanation:** The goal of pharmacological treatment in alcohol dependence is to maintain abstinence and reduce craving. **Fluoxetine** is a Selective Serotonin Reuptake Inhibitor (SSRI) primarily used for Depression and Anxiety disorders. While it may be used to treat comorbid depression in an alcoholic patient, it has **no proven efficacy** in preventing relapse or reducing alcohol consumption in non-depressed patients. **Analysis of Options:** * **Acamprosate (Option C):** An NMDA receptor antagonist and GABA-A agonist. It restores the chemical balance in the brain disrupted by chronic alcohol use. It is a first-line drug specifically used to **maintain abstinence** (reduce the "desire" to drink). * **Nalmefene (Option B):** An opioid system modulator (mu/delta antagonist and kappa partial agonist). Similar to Naltrexone, it is used to **reduce the "reward"** associated with drinking and decrease heavy drinking days. * **Topiramate (Option D):** An anti-epileptic that facilitates GABA neurotransmission and inhibits glutamate. It is an "off-label" but evidence-based second-line agent used to **reduce cravings** and promote abstinence. **High-Yield Clinical Pearls for NEET-PG:** * **FDA-Approved drugs for Alcohol Dependence:** Disulfiram (Aversion therapy), Acamprosate, and Naltrexone. * **Acamprosate** is preferred in patients with **liver disease** (excreted renally). * **Naltrexone** is preferred in patients with **renal failure** (metabolized by the liver) but is contraindicated in acute hepatitis or opioid users. * **Disulfiram** acts by inhibiting **Aldehyde Dehydrogenase**, leading to the accumulation of Acetaldehyde (causing the unpleasant Disulfiram-Ethanol Reaction).

Question 197: A young man with known heroin addiction is brought to the emergency department in an unconscious state. On examination, the patient has decreased bowel sounds, depressed respiration, and pinpoint pupils. What is the treatment of choice for this patient?

A. Oral naltrexone
B. IV naloxone (Correct Answer)
C. Oral diazepam
D. Oral buprenorphine

Explanation: ### Explanation **Correct Answer: B. IV naloxone** **Medical Concept:** The patient presents with the classic **"Opioid Overdose Triad"**: coma (unconscious state), respiratory depression, and miosis (pinpoint pupils). The presence of decreased bowel sounds further confirms opioid toxicity, as opioids slow gastrointestinal motility. In an acute emergency involving respiratory depression, the treatment of choice is **IV Naloxone**. Naloxone is a competitive opioid receptor antagonist with a high affinity for $\mu$-receptors, rapidly reversing the life-threatening effects of the overdose. **Why Incorrect Options are Wrong:** * **A. Oral Naltrexone:** While naltrexone is an opioid antagonist, it is used for **relapse prevention** in detoxified patients. It has a slow onset and is administered orally, making it useless and dangerous (due to aspiration risk) in an acute emergency. * **C. Oral Diazepam:** Diazepam is a benzodiazepine. Giving a sedative to a patient with respiratory depression would worsen the condition and potentially lead to death. * **D. Oral Buprenorphine:** This is a partial $\mu$-agonist used for **maintenance therapy** or substitution. Administering it during an acute overdose would not reverse respiratory depression and could complicate the clinical picture. **High-Yield Clinical Pearls for NEET-PG:** * **Naloxone Half-life:** It has a shorter half-life (30–90 mins) than most opioids (e.g., methadone). Patients must be monitored closely for **"re-narcotization"** as the antagonist wears off. * **Pinpoint Pupils Exception:** Pethidine (Meperidine) overdose typically presents with **mydriasis** (dilated pupils) rather than miosis due to its atropine-like effects. * **Diagnostic Triad:** Coma + Pinpoint pupils + Respiratory rate < 12/min = Opioid Overdose until proven otherwise.

Question 198: Delirium tremens is typically seen in which of the following conditions?

A. Alcohol withdrawal (Correct Answer)
B. Alcohol overdose
C. Morphine poisoning
D. Atropine poisoning

Explanation: **Explanation:** **Delirium Tremens (DT)** is the most severe and life-threatening manifestation of **alcohol withdrawal**. It typically occurs 48 to 96 hours after the last drink in chronic heavy drinkers. The underlying pathophysiology involves a sudden drop in blood alcohol levels, leading to a state of **NMDA receptor overactivity** and **GABAergic hypoactivity**. This results in profound autonomic instability (tachycardia, hypertension, fever) and altered sensorium characterized by clouding of consciousness, vivid hallucinations (often visual or tactile), and severe tremors. **Analysis of Options:** * **Alcohol withdrawal (Correct):** DT is the "Stage 4" of withdrawal. It is a medical emergency with a mortality rate of up to 5% if untreated. * **Alcohol overdose:** Presents as central nervous system depression, respiratory depression, and coma (the "drunk" state), rather than the hyper-excitable state of delirium. * **Morphine poisoning:** Opioid overdose typically presents with the classic triad of miosis (pinpoint pupils), coma, and respiratory depression. * **Atropine poisoning:** While it causes "central anticholinergic syndrome" (delirium, hallucinations), it is clinically distinct. The mnemonic "Mad as a hatter, Red as a beet, Dry as a bone" characterizes atropine toxicity, not alcohol withdrawal. **High-Yield Clinical Pearls for NEET-PG:** * **Timeline:** Minor withdrawal (6–12h) → Seizures (12–48h) → Hallucinosis (12–48h) → **Delirium Tremens (48–96h)**. * **Drug of Choice:** Benzodiazepines (e.g., **Diazepam** or **Lorazepam**). Lorazepam is preferred in patients with liver failure (mnemonic: **OTL** - Oxazepam, Temazepam, Lorazepam). * **Hallucinations:** In DT, consciousness is clouded; in Alcoholic Hallucinosis, the sensorium is clear. * **Mortality:** Usually due to cardiovascular collapse, hyperthermia, or self-injury.

Question 199: Which of the following drugs may induce a psychosis that is easily confused with, or misdiagnosed as, paranoid schizophrenia?

A. Barbiturates
B. Heroin
C. Benzodiazepines
D. Amphetamines (Correct Answer)

Explanation: **Explanation:** **Amphetamines** are potent central nervous system stimulants that increase synaptic concentrations of dopamine. The "Dopamine Hypothesis" of schizophrenia suggests that overactivity of dopamine in the mesolimbic pathway leads to positive symptoms. Consequently, amphetamine-induced psychosis can present with a clinical picture nearly identical to **Paranoid Schizophrenia**, characterized by: * Prominent persecutory delusions. * Auditory and visual hallucinations. * Clear sensorium (unlike delirium). * Extreme agitation or aggressive behavior. **Why the other options are incorrect:** * **Barbiturates & Benzodiazepines (A & C):** These are CNS depressants. Their acute intoxication typically presents with sedation, ataxia, and slurred speech. While their *withdrawal* can cause delirium and hallucinations, the acute state does not mimic paranoid schizophrenia. * **Heroin (B):** As an opioid, heroin causes euphoria, respiratory depression, and "pinpoint" pupils. It does not typically induce a functional-appearing psychotic state. **High-Yield Clinical Pearls for NEET-PG:** * **Formication:** A classic sign of stimulant psychosis (Amphetamines/Cocaine) is the sensation of insects crawling under the skin (also known as "Magnan’s sign" or "cocaine bugs"). * **Differentiation:** Amphetamine psychosis usually resolves within days to weeks of abstinence, whereas schizophrenia is a chronic, deteriorating condition. * **Management:** Acute agitation in stimulant psychosis is managed with **Benzodiazepines** (first-line) or high-potency antipsychotics like Haloperidol.

Question 200: In a chronic alcoholic, what is the cause of memory loss and confabulation?

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

Explanation: ### Explanation The correct answer is **Korsakoff’s psychosis**. This condition is a late-stage manifestation of **thiamine (Vitamin B1) deficiency**, typically occurring after one or more episodes of Wernicke’s encephalopathy. **Why Korsakoff’s Psychosis is Correct:** Korsakoff’s syndrome is characterized by a profound **anterograde amnesia** (inability to form new memories) and **retrograde amnesia**. To fill these gaps in memory, patients subconsciously create imaginary experiences, a hallmark clinical sign known as **confabulation**. The underlying pathology involves bilateral lesions in the **mammillary bodies** and the dorsomedial nucleus of the thalamus. **Analysis of Incorrect Options:** * **A. Wernicke’s Encephalopathy:** This is the acute, reversible phase of thiamine deficiency. It is characterized by the classic triad: **Ophthalmoplegia** (ataxia), **Confusion**, and **Ataxia** (Global Confusion). While it often precedes Korsakoff’s, it does not typically feature confabulation. * **C. Alcoholic Hallucinosis:** This occurs within 12–24 hours of abstinence. It involves vivid auditory hallucinations (usually derogatory) in a patient with a **clear sensorium** (the patient is conscious and oriented). * **D. Delirium Tremens:** The most severe form of alcohol withdrawal (48–96 hours). It is characterized by clouded consciousness, autonomic hyperactivity (tachycardia, fever), and vivid visual hallucinations, rather than isolated memory loss. **High-Yield Clinical Pearls for NEET-PG:** * **Wernicke-Korsakoff Syndrome (WKS):** Often viewed as a continuum. Wernicke is acute/reversible; Korsakoff is chronic/irreversible. * **Confabulation:** Defined as "honest lying"—the patient is not intentionally deceiving but filling memory voids. * **Treatment Precaution:** Always administer **Thiamine before Glucose** in a chronic alcoholic. Giving glucose first can precipitate Wernicke’s encephalopathy by exhausting remaining thiamine stores. * **Imaging:** MRI may show atrophy of the **mammillary bodies**.

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

Practice Questions

Hallucinogen-Related Disorders

Practice Questions

Substance Withdrawal Syndromes

Practice Questions

Pharmacotherapy for Substance Use Disorders

Practice Questions

Psychosocial Interventions

Practice Questions

Dual Diagnosis Management

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free