Drugs in Psychiatric Disorders Practice Questions

Q: The clinical effects of antidepressant drugs are mainly based on?

Change in neurotransmitter receptor sensitivity. ***B. Change in neurotransmitter receptor sensitivity*** - While many antidepressants initially alter neurotransmitter levels by blocking reuptake, their delayed therapeutic effects (weeks) are thought to be mediated by **adaptive changes** in postsynaptic receptor sensitivity and gene expression, leading to **downregulation of hypersensitive receptors**. - This **receptor plasticity** is crucial for long-term clinical improvement, as the brain adapts to sustained changes in neurotransmitter availability. *A. Reduction in neurotransmitter levels* - This option is incorrect as antidepressants generally aim to **increase** the functional availability of **neurotransmitters** like serotonin and norepinephrine within the synaptic cleft. - A reduction in neurotransmitter levels would typically exacerbate depressive symptoms, not alleviate them. *C. Modification of neurotransmitter signaling pathways* - While antidepressants do ultimately affect intracellular signaling pathways, this is often a **downstream consequence** of changes in receptor sensitivity and neurotransmitter binding, rather than the primary *main* basis of their clinical effects. - This option is broader and less precise than the change in receptor sensitivity, missing the direct impact on how neurons respond to available neurotransmitters. *D. Inhibition of neurotransmitter reuptake* - This describes the **initial and acute mechanism of action** for many antidepressant classes (e.g., SSRIs, SNRIs) by increasing the concentration of neurotransmitters in the synaptic cleft. - However, the **clinical antidepressant effects** often take several weeks to manifest, suggesting that this acute increase in neurotransmitter availability is not the sole or primary basis for long-term symptom relief, but rather initiates the adaptive changes in receptor sensitivity.

Q: Which receptor is most commonly targeted by typical antipsychotics?

D2. ***Correct: D2*** - **Typical antipsychotics** (first-generation antipsychotics) primarily exert their therapeutic effects by blocking **dopamine D2 receptors** in the mesolimbic pathway, thereby reducing positive symptoms of psychosis such as hallucinations and delusions. - The degree of **D2 receptor blockade** correlates directly with **clinical efficacy** for typical antipsychotics. - High-potency typical antipsychotics like haloperidol have strong D2 receptor affinity, while low-potency agents like chlorpromazine also work primarily through D2 blockade. - D2 blockade in the nigrostriatal pathway is responsible for extrapyramidal side effects (EPS), a hallmark of typical antipsychotics. *Incorrect: D1* - **D1 receptors** are dopaminergic receptors involved in cognitive and motor functions, but their blockade is not the primary mechanism of action of typical antipsychotics. - While some antipsychotics may have D1 affinity, this is not what defines typical antipsychotics or drives their therapeutic efficacy. *Incorrect: D3* - **Dopamine D3 receptors** are involved in the limbic system and may play a role in some antipsychotic effects, but they are not the primary target for **typical antipsychotics**. - Some newer atypical antipsychotics have higher affinity for D3 receptors, but this is not characteristic of first-generation typical agents. *Incorrect: D4* - **D4 receptors** have high affinity for certain atypical antipsychotics like **clozapine**, but this is not the main receptor target for **typical antipsychotics**. - D4 receptor selectivity is more associated with atypical rather than typical antipsychotic profiles.

Q: Weight gain is seen with all of the following antipsychotic medications except?

Molindone. ***Molindone*** - **Molindone** is an antipsychotic known for its **low risk of weight gain** and has even been associated with weight loss in some patients. - Its mechanism of action, involving **dopamine D2 antagonism** without significant antagonism of histamine H1 or serotonin 5-HT2C receptors, contributes to its favorable metabolic profile. *Quetiapine* - **Quetiapine** is a common second-generation antipsychotic associated with a **moderate to high risk of weight gain**. - Its affinity for **histamine H1** and **serotonin 5-HT2C receptors** is thought to contribute to its weight-increasing effects. *Risperidone* - **Risperidone** carries a **moderate risk of weight gain**, especially at higher doses, making it a less desirable option if metabolic side effects are a major concern. - This effect is linked to its antagonism of **serotonin 5-HT2C receptors** and, to a lesser extent, **histamine H1 receptors**. *Clozapine* - **Clozapine** is associated with the **highest risk of weight gain** among all antipsychotics, often leading to significant metabolic disturbances. - Its strong antagonism of multiple receptors, including **histamine H1**, **serotonin 5-HT2C**, and **alpha1-adrenergic receptors**, plays a role in its profound metabolic side effects.

Q: Which of the following statements about aripiprazole is true?

It is used in the treatment of acute mania. ***It is used in the treatment of acute mania*** - Aripiprazole is a **second-generation antipsychotic** approved for the treatment of **acute manic and mixed episodes** associated with bipolar I disorder. - This is a **major FDA-approved indication** and represents one of its most clinically significant uses, making it the best answer among the true statements. - Its efficacy in stabilizing mood through its unique partial agonism at dopamine D2 and serotonin 5-HT1A receptors, along with antagonism at 5-HT2A receptors, makes it suitable for this indication. *It has 5HT1A partial agonist action* - This statement is **factually TRUE** - aripiprazole does have **5-HT1A partial agonist action** as part of its pharmacological profile. - However, this mechanistic detail alone does not represent its primary clinical significance or most distinguishing therapeutic feature. - Its unique mechanism also involves **D2 partial agonism** and 5-HT2A antagonism. *It has low sedating potential* - This statement is also **TRUE** - aripiprazole is well-established as having **low sedating potential** compared to most other antipsychotics. - This is actually one of its **distinguishing advantages** and a key feature that differentiates it from highly sedating antipsychotics like quetiapine or olanzapine. - While sedation can occur in some patients, it is relatively uncommon, and the low sedation profile is a recognized clinical benefit. *Only antipsychotic with D2 partial agonist activity* - This statement is **FALSE** - aripiprazole was one of the first antipsychotics with significant **D2 partial agonist activity**, but it is **not the *only* one**. - Other antipsychotics, such as **brexpiprazole** and **cariprazine**, also exhibit D2 partial agonist activity, distinguishing them from traditional D2 antagonists.

Q: What electrolyte imbalance is commonly associated with lithium use?

Hypercalcemia. ***Hypercalcemia*** - Long-term lithium therapy can lead to an increased risk of developing **primary hyperparathyroidism** (occurs in approximately 10% of chronic users), which subsequently causes hypercalcemia. - Lithium can affect the **set point of the calcium-sensing receptor** in the parathyroid glands, leading to inappropriate secretion of parathyroid hormone (PTH). - This is a **well-recognized complication** of chronic lithium therapy requiring monitoring of calcium and PTH levels. *Hyponatremia* - **Hyponatremia** is actually a frequently encountered electrolyte disturbance with lithium use, occurring through multiple mechanisms: - Lithium-induced **nephrogenic diabetes insipidus** leading to polyuria, polydipsia, and potential dehydration - Interaction with **thiazide diuretics** (which are sometimes used to treat lithium-induced polyuria, paradoxically) - SIADH-like effects in some patients - However, in the context of this examination question, **hypercalcemia due to hyperparathyroidism** is considered the characteristic chronic complication specifically linked to lithium's unique mechanism of action. *Hyperkalemia* - **Hyperkalemia** is not a commonly reported electrolyte imbalance specifically associated with lithium use. - While lithium can affect renal function and cause **renal tubular dysfunction**, this does not typically manifest as hyperkalemia. *Hypokalemia* - **Hypokalemia** is not typically associated with lithium use. - It is more commonly caused by diuretic use, vomiting, or diarrhea rather than lithium therapy directly.

Q: Which of the following typical antipsychotic drugs is least commonly used in depot form?

Chlorpromazine. ***Chlorpromazine*** - Chlorpromazine is a **typical antipsychotic** that is **NOT available in depot form** for clinical use. - It is available only in **oral** and **short-acting injectable** formulations, making it the **least commonly used in depot form** among the options listed. - Its high sedative properties, orthostatic hypotension risk, and pharmacokinetic profile make it unsuitable for long-acting depot formulation. *Haloperidol* - **Haloperidol decanoate** is one of the **most widely used depot formulations** of typical antipsychotics. - Administered intramuscularly every **3-4 weeks**, it is highly effective for **long-term maintenance treatment** in schizophrenia. - Its favorable pharmacokinetic profile makes it ideal for depot preparation. *Fluphenazine* - **Fluphenazine decanoate** and **fluphenazine enanthate** are **well-established depot preparations** with decades of clinical use. - These formulations allow for dosing every **2-4 weeks**, significantly improving **medication adherence** in chronic psychotic disorders. - Fluphenazine depot is a first-line option for long-acting injectable antipsychotic therapy. *Trifluoperazine* - Trifluoperazine is primarily available and used as an **oral medication** for maintenance therapy. - While some limited depot formulations have been reported in older literature, they are **not commonly used in clinical practice**. - However, it is still more available in depot form than chlorpromazine, which has essentially **no depot use**.

Q: What is the mechanism of action of duloxetine?

Inhibition of both serotonin and norepinephrine reuptake. ***Inhibition of both serotonin and norepinephrine reuptake*** - **Duloxetine** is a **serotonin-norepinephrine reuptake inhibitor (SNRI)**, meaning it blocks the reuptake of both neurotransmitters, increasing their concentrations in the synaptic cleft [2]. - This dual action contributes to its efficacy in treating **depression**, **anxiety disorders**, and **neuropathic pain** [2], [3]. *Selective serotonin reuptake inhibition* - This describes the mechanism of **SSRIs (Selective Serotonin Reuptake Inhibitors)**, such as fluoxetine or sertraline, which primarily target serotonin [1]. - Duloxetine's mechanism is broader, affecting both serotonin and norepinephrine [2]. *Selective norepinephrine reuptake inhibition* - This mechanism is characteristic of medications like **atomoxetine**, used for ADHD, which primarily targets norepinephrine. - Duloxetine has a dual action, not selective to norepinephrine alone. *No effect on neurotransmitter reuptake* - Medications with no effect on neurotransmitter reuptake would not typically be effective as antidepressants or treatments for neuropathic pain. - Duloxetine's therapeutic effects are directly linked to its inhibition of reuptake for both serotonin and norepinephrine [2], [4].

Q: What is the mechanism of action of buspirone?

Partial agonism at the 5-HT1A receptor.. ***Partial agonism at the 5-HT1A receptor.*** - Buspirone is known to act primarily as a **partial agonist** at the **serotonin 5-HT1A receptor**, which is responsible for its anxiolytic effects. - This action helps to modulate serotonin neurotransmission, leading to a reduction in anxiety symptoms without significant sedative or addictive properties. *Antagonism at the 5-HT1B receptor.* - While 5-HT1B receptors are involved in serotonin regulation, buspirone's primary anxiolytic effect is not mediated through **antagonism** at these receptors. - Antagonism at 5-HT1B receptors is not a prominent mechanism for typical anxiolytic medications like buspirone. *Antagonism at the 5-HT2C receptor.* - **Antagonism at the 5-HT2C receptor** is sometimes associated with **atypical antipsychotics** and their metabolic side effects, but it is not the primary mechanism of action for buspirone. - Buspirone is not generally considered an antipsychotic and its effects are distinct from those driven by 5-HT2C antagonism. *Partial agonism at the 5-HT1B receptor.* - Buspirone's main anxiolytic action is distinctly linked to the **5-HT1A receptor**, not the 5-HT1B receptor. - Although serotonin receptors are numerous and complex, buspirone's specific therapeutic profile arises from its interaction with 5-HT1A.

Q: Which of the following actions is NOT associated with tricyclic antidepressants?

MAO inhibition. ***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.

Q: What is the treatment for extrapyramidal side effects induced by Haloperidol?

Anticholinergic drugs. ***Anticholinergic drugs (effective treatment)*** - **Anticholinergic medications**, such as **benztropine** or **diphenhydramine**, are the primary treatment for **acute extrapyramidal symptoms (EPS)** like dystonia and parkinsonism induced by antipsychotics like haloperidol. - They work by **blocking muscarinic acetylcholine receptors**, helping to restore the balance between dopamine and acetylcholine in the basal ganglia. *Benzodiazepines (used for anxiety and muscle relaxation)* - While benzodiazepines can offer some relief for **akathisia** (a form of EPS characterized by restlessness) due to their sedative and muscle relaxant properties, they are **not the first-line treatment for other acute EPS** such as dystonia or parkinsonism. - They primarily enhance **GABAergic transmission** and are effective for anxiety and seizure control rather than direct antagonism of EPS mechanisms. *Barbiturates (used as sedative-hypnotic drugs)* - **Barbiturates** are strong central nervous system depressants used for sedation, anesthesia, and seizure control, but are **not indicated for the treatment of EPS**. - Their significant **sedative and addictive potential**, along with a narrow therapeutic index, makes them unsuitable for this purpose. *SSRIs (used for depression and anxiety)* - **SSRIs (Selective Serotonin Reuptake Inhibitors)** are antidepressants that work by increasing serotonin levels in the brain and are used to treat depression, anxiety, and obsessive-compulsive disorder. - They **do not have a direct role** in ameliorating dopamine-acetylcholine imbalance responsible for haloperidol-induced EPS.

Question 1

The clinical effects of antidepressant drugs are mainly based on?

Accepted Answer

Change in neurotransmitter receptor sensitivity

Answer

Reduction in neurotransmitter levels

Answer

Modification of neurotransmitter signaling pathways

Answer

Inhibition of neurotransmitter reuptake

Question 2

Which receptor is most commonly targeted by typical antipsychotics?

Accepted Answer

D2

Answer

D1

Answer

D3

Answer

D4

Question 3

Weight gain is seen with all of the following antipsychotic medications except?

Accepted Answer

Molindone

Answer

Risperidone

Answer

Clozapine

Answer

Quetiapine

Question 4

Which of the following statements about aripiprazole is true?

Accepted Answer

It is used in the treatment of acute mania

Answer

It has low sedating potential

Answer

It has 5HT1A partial agonist action

Answer

Only antipsychotic with D2 partial agonist activity

Question 5

What electrolyte imbalance is commonly associated with lithium use?

Accepted Answer

Hypercalcemia

Answer

Hyponatremia

Answer

Hyperkalemia

Answer

Hypokalemia

Question 6

Which of the following typical antipsychotic drugs is least commonly used in depot form?

Accepted Answer

Chlorpromazine

Answer

Haloperidol

Answer

Fluphenazine

Answer

Trifluoperazine

Question 7

What is the mechanism of action of duloxetine?

Accepted Answer

Inhibition of both serotonin and norepinephrine reuptake

Answer

Selective serotonin reuptake inhibition

Answer

Selective norepinephrine reuptake inhibition

Answer

No effect on neurotransmitter reuptake

Question 8

What is the mechanism of action of buspirone?

Accepted Answer

Partial agonism at the 5-HT1A receptor.

Answer

Antagonism at the 5-HT1B receptor.

Answer

Antagonism at the 5-HT2C receptor.

Answer

Partial agonism at the 5-HT1B receptor.

Question 9

Which of the following actions is NOT associated with tricyclic antidepressants?

Accepted Answer

MAO inhibition

Answer

Block 5-HT or NE reuptake

Answer

Anticholinergic action

Answer

Causes sedation

Question 10

What is the treatment for extrapyramidal side effects induced by Haloperidol?

Accepted Answer

Anticholinergic drugs

Answer

Barbiturates

Answer

SSRIs

Answer

Benzodiazepines

Drugs in Psychiatric Disorders — MCQs

Drugs in Psychiatric Disorders — MCQs

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