Anxiolytics and Hypnotics — MCQs
Which of the following neurotransmitters is NOT suspected to be involved in the pathophysiology of schizophrenia?
Modafinil is approved by FDA for treatment of all except:
How do benzodiazepines exert their sedative effects?
Which of the following actions is NOT associated with tricyclic antidepressants?
Diazepam poisoning is treated by:
Drug of choice for night terrors:
Which of the following dependence-causing drugs is most commonly abused worldwide?
Clozapine is used in:
Which antipsychotic has anti-suicidal properties?
Use of lithium in pregnancy can result in which of the following abnormalities in the baby?
Anxiolytics and Hypnotics Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following neurotransmitters is NOT suspected to be involved in the pathophysiology of schizophrenia?
- A. Ascorbic acid (Correct Answer)
- B. Serotonin (5-HT)
- C. Norepinephrine
- D. Glutamate
Explanation: ***Ascorbic acid*** - **Ascorbic acid (Vitamin C)** is an important antioxidant and cofactor, but it is **not a neurotransmitter**. - While it may have neuroprotective roles, there is **no significant theory** suggesting ascorbic acid dysregulation is involved in the core pathophysiology of schizophrenia. - Unlike the other options, ascorbic acid is not part of any major neurotransmitter hypothesis of schizophrenia. *Serotonin (5-HT)* - The **serotonin hypothesis** of schizophrenia suggests an imbalance in serotonergic activity, particularly involving **5-HT2A receptors**. - Serotonin is targeted by **atypical antipsychotics** (e.g., risperidone, olanzapine) which block 5-HT2A receptors. - Serotonin dysregulation is believed to contribute to both **positive and negative symptoms** of schizophrenia. *Norepinephrine* - Dysregulation of **norepinephrine** has been implicated in the **cognitive and negative symptoms** of schizophrenia. - Alterations in noradrenergic systems contribute to deficits in **attention, working memory, and motivation** in affected individuals. - The prefrontal cortex noradrenergic system is particularly relevant to schizophrenia pathophysiology. *Glutamate* - The **NMDA receptor hypofunction hypothesis** is a major theory in schizophrenia pathophysiology. - **Glutamate** dysfunction, particularly involving NMDA receptors, can explain positive, negative, and cognitive symptoms. - NMDA receptor antagonists (like PCP and ketamine) can **induce psychotic symptoms** similar to schizophrenia, supporting this hypothesis.
Question 2: Modafinil is approved by FDA for treatment of all except:
- A. Narcolepsy
- B. Shift work sleep disorder (SWSD)
- C. Obstructive sleep apnea syndrome (OSAS)
- D. Lethargy in depression (Correct Answer)
Explanation: ***Lethargy in depression*** - Modafinil is **not FDA-approved** for treating lethargy or fatigue specifically in the context of depression. Its primary indications are for disorders of excessive daytime sleepiness. - While it may be used off-label in some cases for depression-related fatigue, it lacks formal FDA approval and specific efficacy data for this indication. *Narcolepsy* - Modafinil is **FDA-approved** as a wakefulness-promoting agent for the treatment of excessive daytime sleepiness associated with **narcolepsy**. - It helps reduce the frequency and severity of sleep attacks by promoting wakefulness through effects on **dopamine**, **norepinephrine**, and **histamine** systems in the brain. *Shift work sleep disorder (SWSD)* - Modafinil is **FDA-approved** to improve wakefulness in patients with excessive sleepiness associated with **shift work sleep disorder**. - It helps individuals working non-traditional hours (night shifts, rotating shifts) maintain alertness during their work periods. *Obstructive sleep apnea syndrome (OSAS)* - Modafinil is **FDA-approved** as an **adjunctive treatment** for residual excessive daytime sleepiness in patients with **obstructive sleep apnea/hypopnea syndrome (OSAHS)** who are receiving adequate treatment with CPAP. - It addresses persistent sleepiness that remains even after appropriate primary airway management.
Question 3: How do benzodiazepines exert their sedative effects?
- A. They enhance GABAergic transmission. (Correct Answer)
- B. They increase norepinephrine levels and enhance GABA transmission.
- C. They block dopamine receptors and enhance GABA transmission.
- D. They inhibit acetylcholine release and enhance GABA transmission.
Explanation: ***They enhance GABAergic transmission.*** - Benzodiazepines bind to a specific site on the **GABA-A receptor**, increasing its affinity for the **neurotransmitter GABA**. - This binding leads to an increased frequency of **chloride channel opening**, hyperpolarizing the neuron and making it less excitable, which produces sedative effects. *They increase norepinephrine levels and enhance GABA transmission.* - While benzodiazepines enhance GABA transmission, they do **not primarily increase norepinephrine levels**. - Medications that increase norepinephrine levels, such as certain antidepressants, typically have stimulating rather than sedative effects. *They block dopamine receptors and enhance GABA transmission.* - While benzodiazepines enhance GABA transmission, they do **not block dopamine receptors**. - Blocking dopamine receptors is the primary mechanism of action for many **antipsychotic medications**, which have different pharmacological profiles and side effects compared to benzodiazepines. *They inhibit acetylcholine release and enhance GABA transmission.* - While benzodiazepines enhance GABA transmission, they generally do **not directly inhibit acetylcholine release**. - Muscarinic acetylcholine receptor antagonists (anticholinergics) inhibit acetylcholine and can cause sedation, but this is a distinct mechanism from benzodiazepines.
Question 4: Which of the following actions is NOT associated with tricyclic antidepressants?
- A. Block 5-HT or NE reuptake
- B. Anticholinergic action
- C. MAO inhibition (Correct Answer)
- D. Causes sedation
Explanation: ***MAO inhibition*** - Tricyclic antidepressants (TCAs) primarily exert their effects by inhibiting the reuptake of **norepinephrine** and **serotonin**, not by inhibiting monoamine oxidase (MAO). - **MAO inhibitors** are a distinct class of antidepressants with a different mechanism of action and side effect profile. *Anticholinergic action* - Many TCAs have significant **anticholinergic effects**, blocking muscarinic receptors and leading to side effects like dry mouth, constipation, and blurred vision. - These effects contribute to the **adverse event profile** of TCAs, especially in elderly patients. *Block 5-HT or NE reuptake* - The primary mechanism of action of TCAs involves the **inhibition of serotonin (5-HT)** and **norepinephrine (NE) reuptake** into presynaptic neurons. - This action increases the concentration of these neurotransmitters in the **synaptic cleft**, thereby potentiating their effects. *Causes sedation* - TCAs frequently cause **sedation**, particularly the more histaminergic ones (e.g., amitriptyline, doxepin), due to their **histamine H1 receptor antagonism**. - This side effect can be beneficial for patients with insomnia but can be problematic for daytime functioning.
Question 5: Diazepam poisoning is treated by:
- A. Resins
- B. Hemofiltration
- C. Charcoal
- D. Flumazenil (Correct Answer)
Explanation: ***Flumazenil*** - **Flumazenil** is a **benzodiazepine receptor antagonist** that competitively binds to the benzodiazepine binding site on the GABA-A receptor, reversing the effects of diazepam. - It is used in cases of severe benzodiazepine overdose causing **respiratory depression** or **severe sedation**. *Resins* - **Resins**, such as **cholestyramine**, are typically used to bind toxins or drugs in the **gastrointestinal tract** that undergo enterohepatic recirculation. - They are generally not effective for reversing the central nervous system depression caused by a benzodiazepine overdose. *Hemofiltration* - **Hemofiltration** is a form of renal replacement therapy used to remove small and middle molecular weight substances from the blood. - While it can remove some drugs, **diazepam** is highly **lipophilic** and extensively **protein-bound**, making it poorly amenable to removal by hemofiltration. *Charcoal* - **Activated charcoal** is used to prevent the absorption of ingested toxins from the gastrointestinal tract. - It is effective when administered soon after ingestion but does not reverse the established effects of an absorbed drug like diazepam in an overdose situation.
Question 6: Drug of choice for night terrors:
- A. Tricyclic antidepressant
- B. Meprobamate
- C. Diazepam
- D. Clonazepam (Correct Answer)
Explanation: ***Clonazepam*** - **Clonazepam**, a benzodiazepine, is the **drug of choice** for night terrors due to its ability to suppress Stage 3 and 4 **slow-wave sleep**, where night terrors occur. - Its sedative and anxiolytic effects help to calm the patient and reduce the frequency and severity of these episodes. *Tricyclic antidepressant* - While some **tricyclic antidepressants** (TCAs) have sedative properties, they are generally not the first-line treatment for night terrors. - Their side effect profile and potential to alter other sleep stages make them less suitable than benzodiazepines for this specific parasomnia. *Meprobamate* - **Meprobamate** is an anxiolytic and sedative drug that is largely historical and has been replaced by safer and more effective alternatives like benzodiazepines. - It has a higher risk of dependence and side effects compared to modern treatments for sleep disorders. *Diazepam* - **Diazepam** is another benzodiazepine, but **clonazepam** is generally preferred for night terrors due to its longer half-life and specific efficacy in suppressing slow-wave sleep. - While diazepam could offer some relief, clonazepam is considered more effective for sustained management of this condition.
Question 7: Which of the following dependence-causing drugs is most commonly abused worldwide?
- A. Cannabis (Correct Answer)
- B. Heroin
- C. Amphetamine
- D. Cocaine
Explanation: ***Cannabis*** - **Cannabis** is the most widely cultivated and consumed illicit drug globally, with the highest prevalence of past-year use. - Its widespread availability, relatively lower perception of harm compared to other drugs, and varied forms of consumption (smoking, edibles) contribute to its extensive abuse. *Heroin* - **Heroin** is a highly addictive opioid that causes severe physical dependence and withdrawal symptoms, but its global prevalence is significantly lower than that of cannabis. - Its high cost, illicit nature, and significant health risks, including overdose, limit its abuse to a smaller, though critically affected, population. *Amphetamine* - **Amphetamines**, including methamphetamine, are potent central nervous system stimulants with a significant abuse potential, leading to psycho-behavioral and physical dependence. - While prevalent in certain regions and among specific populations, their overall global abuse statistics are lower than those for cannabis. *Cocaine* - **Cocaine** is a powerful stimulant derived from the coca plant, known for its strong psychological dependence and significant health consequences. - Its abuse is concentrated in specific geographical areas and demographic groups, making its global prevalence of abuse lower than that of cannabis.
Question 8: Clozapine is used in:
- A. Depression
- B. Resistant schizophrenia (Correct Answer)
- C. Mania
- D. Delirium
Explanation: **Explanation:** **Clozapine** is an atypical (second-generation) antipsychotic and is considered the **gold standard** for the management of **Treatment-Resistant Schizophrenia (TRS)**. 1. **Why Option B is Correct:** Resistance in schizophrenia is defined as a lack of satisfactory clinical improvement despite the use of adequate doses of at least two different antipsychotics (including one atypical) for a duration of 6–8 weeks each. Clozapine is uniquely effective in these cases due to its complex receptor profile (low D2 affinity, high 5-HT2A, D4, and alpha-adrenergic blockade). It is the only antipsychotic proven to reduce suicidal behavior in schizophrenic patients. 2. **Why Other Options are Incorrect:** * **A. Depression:** First-line treatments are SSRIs/SNRIs. While some atypicals (like Quetiapine or Aripiprazole) are used as adjuncts in resistant depression, Clozapine is not used due to its side-effect profile. * **C. Mania:** Acute mania is treated with Lithium, Valproate, or standard antipsychotics (e.g., Olanzapine, Risperidone). Clozapine is reserved only for ultra-resistant cases, not as a standard indication. * **D. Delirium:** Low-dose Haloperidol is the drug of choice. Clozapine is contraindicated in delirium because its strong anticholinergic properties can worsen the confusional state. **High-Yield Clinical Pearls for NEET-PG:** * **Agranulocytosis:** The most dreaded side effect (occurs in ~1%). Mandatory **WBC monitoring** is required (weekly for the first 6 months). * **Seizures:** Clozapine carries a dose-dependent risk of seizures. * **Sialorrhea:** Paradoxical hypersalivation is a common, bothersome side effect. * **Myocarditis:** A rare but fatal side effect; monitor for tachycardia and chest pain. * **Metabolic Syndrome:** High risk of weight gain and diabetes (similar to Olanzapine).
Question 9: Which antipsychotic has anti-suicidal properties?
- A. clozapine (Correct Answer)
- B. chlorpromazine
- C. aripiprazole
- D. amisulpride
Explanation: **Explanation:** **Clozapine** is the correct answer because it is the only antipsychotic with a specifically FDA-approved indication for reducing the risk of recurrent suicidal behavior in patients with schizophrenia or schizoaffective disorder. This anti-suicidal effect is independent of its primary antipsychotic action and is believed to be mediated by its unique modulation of serotonergic (5-HT2A) and noradrenergic systems, which helps reduce impulsivity and aggression. **Analysis of Incorrect Options:** * **B. Chlorpromazine:** A typical (first-generation) antipsychotic primarily used for acute psychosis. While it treats positive symptoms, it has no proven specific anti-suicidal properties and may even worsen depressive symptoms in some patients. * **C. Aripiprazole:** A partial dopamine agonist. While effective for mood stabilization and augmentation in depression, it does not carry a specific indication for suicide prevention. * **D. Amisulpride:** A substituted benzamide that is effective for both positive and negative symptoms of schizophrenia, but lacks evidence for a direct anti-suicidal effect. **High-Yield Clinical Pearls for NEET-PG:** * **The "Rule of Two":** There are two main drugs in psychiatry known for reducing suicide risk: **Clozapine** (in Schizophrenia) and **Lithium** (in Bipolar Disorder). * **Clozapine Monitoring:** Due to the risk of **agranulocytosis**, regular monitoring of Absolute Neutrophil Count (ANC) is mandatory. * **Other Side Effects:** Clozapine is associated with the highest risk of seizures (dose-dependent), sialorrhea (drooling), myocarditis, and metabolic syndrome among antipsychotics. * **Indication:** It remains the gold standard for **Treatment-Resistant Schizophrenia** (defined as failure of two adequate trials of other antipsychotics).
Question 10: Use of lithium in pregnancy can result in which of the following abnormalities in the baby?
- A. Anencephaly
- B. Ebstein's anomaly (Correct Answer)
- C. Caudal dysgenesis syndrome
- D. Elfin facies
Explanation: **Explanation:** The correct answer is **Ebstein’s anomaly**. Lithium is a mood stabilizer used primarily for Bipolar Disorder. When taken during the first trimester of pregnancy, it acts as a teratogen, specifically affecting cardiac development. **1. Why Ebstein’s Anomaly is Correct:** Ebstein’s anomaly is a rare congenital heart defect characterized by the **downward displacement of the tricuspid valve** leaflets into the right ventricle ("atrialization" of the right ventricle). While the absolute risk remains low (approx. 1 in 1,000 to 2,000 exposures), it represents a significant increase compared to the general population. **2. Analysis of Incorrect Options:** * **Anencephaly:** This is a neural tube defect (NTD). NTDs are more commonly associated with **Valproate** or Carbamazepine use during pregnancy, not Lithium. * **Caudal dysgenesis syndrome:** This is a rare malformation (sacral agenesis) highly specific to **maternal diabetes mellitus**. * **Elfin facies:** This facial phenotype (along with hypercalcemia and supravalvular aortic stenosis) is characteristic of **Williams Syndrome**, a genetic deletion on chromosome 7. **Clinical Pearls for NEET-PG:** * **Monitoring:** If a pregnant woman must continue Lithium, fetal echocardiography is recommended at 18–22 weeks. * **Dosage:** Lithium clearance increases during pregnancy (due to increased GFR) and drops abruptly at delivery; close serum monitoring is vital to avoid toxicity. * **Breastfeeding:** Lithium is generally discouraged during breastfeeding as it is excreted in milk and can cause "Floppy Baby Syndrome" (hypotonia, cyanosis). * **Alternative:** Lamotrigine is often considered a safer mood stabilizer during pregnancy regarding structural malformations.
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