Drugs in Psychiatric Disorders Practice Questions

Q: Which of the following is NOT a side effect of depression?

Flupenthixol. **Explanation:** The question asks to identify the drug that does **not** cause depression as a side effect. The correct answer is **Flupenthixol**. **1. Why Flupenthixol is the correct answer:** Flupenthixol is a thioxanthene derivative (typical antipsychotic). While high doses are used to treat psychosis, **low doses (0.5–1.5 mg)** have a unique **activating and antidepressant effect**. It is often used clinically to treat mild-to-moderate depression with anxiety or psychosomatic symptoms. Therefore, it is a treatment for depression rather than a cause. **2. Why the other options are incorrect (Drugs causing depression):** * **Propranolol:** Beta-blockers, particularly lipophilic ones like Propranolol, cross the blood-brain barrier and are well-documented to cause CNS side effects, including fatigue, lethargy, and clinical depression. * **Oral Contraceptives (OCPs):** Estrogen and progesterone can influence neurotransmitter levels (like serotonin). Chronic use of OCPs is a known risk factor for mood swings and depressive symptoms in susceptible women. * **Reserpine:** This is a classic pharmacological example. Reserpine inhibits the Vesicular Monoamine Transporter (VMAT), leading to the depletion of norepinephrine, dopamine, and serotonin. This depletion directly led to the "Monoamine Hypothesis" of depression. **Clinical Pearls for NEET-PG:** * **Reserpine-induced depression** is a high-yield fact; it is contraindicated in patients with a history of mental illness. * Other drugs causing depression: **Corticosteroids, Interferon-alpha, Methyldopa, and Isotretinoin.** * **Flupenthixol** is often combined with Melitracen (a TCA) in clinical practice for its rapid onset of mood-elevating effects.

Q: What is the half-life of lithium?

24 hours. **Lithium** is the gold-standard mood stabilizer used for Bipolar Affective Disorder (BPAD) [2]. Understanding its pharmacokinetics is crucial for clinical practice and exam preparation.Why 24 hours is correct:The average elimination half-life of lithium in an adult with normal renal function is approximately **24 hours** (ranging typically from 18 to 30 hours). Because it takes roughly 4 to 5 half-lives to reach a steady-state plasma concentration, lithium requires about **5 days** of consistent dosing to achieve stable therapeutic levels. This long half-life allows for once or twice-daily dosing.Analysis of incorrect options:* **8 hours (A):** This is too short. While lithium is rapidly absorbed [1], its elimination is slow because it undergoes extensive renal reabsorption (80% in the proximal tubule) [1].* **16 hours (B):** While some younger patients with high glomerular filtration rates may have shorter half-lives, 24 hours is the standard physiological mean cited in major pharmacology texts (Katzung, KD Tripathi).* **36 hours (D):** This is longer than the average; however, the half-life can extend to 36 hours or more in elderly patients or those with renal impairment, increasing the risk of toxicity.High-Yield Clinical Pearls for NEET-PG:* **Therapeutic Index:** Lithium has a very narrow therapeutic index. Monitoring is essential [1].* **Therapeutic Range:** 0.5–0.8 mEq/L (Maintenance); 0.8–1.2 mEq/L (Acute Mania). Toxicity occurs >1.5 mEq/L.* **Sample Timing:** Blood for Therapeutic Drug Monitoring (TDM) should be drawn **12 hours after the last dose**.* **Drug Interactions:** Thiazides, NSAIDs, and ACE inhibitors decrease lithium clearance, leading to toxicity [3].* **Pregnancy:** Associated with **Ebstein’s Anomaly** (tricuspid valve malformation).

Q: Which of the following is NOT an adverse effect of Selective Serotonin Reuptake Inhibitors (SSRIs)?

Galactorrhea. **Explanation:** The correct answer is **D. Galactorrhea**. **1. Why Galactorrhea is the correct choice:** Galactorrhea (inappropriate milk production) is primarily caused by **hyperprolactinemia**. Prolactin secretion is inhibited by **Dopamine** (acting as Prolactin Inhibiting Factor). Drugs that block D2 receptors (like typical antipsychotics) or deplete dopamine (like Reserpine) lead to increased prolactin levels. **SSRIs primarily affect the serotonergic system**, not the dopaminergic pathway, and therefore do not typically cause galactorrhea. **2. Analysis of Incorrect Options:** * **A. Weight changes:** SSRIs can cause initial weight loss, but long-term use (especially with Paroxetine) is frequently associated with **weight gain**. * **B. Diarrhoea:** Serotonin (5-HT) is abundant in the GI tract. By increasing synaptic 5-HT, SSRIs stimulate 5-HT3 and 5-HT4 receptors, leading to nausea, vomiting, and **diarrhoea** (the most common acute side effects). * **C. Delayed ejaculation:** Sexual dysfunction is the most common long-term side effect of SSRIs. It includes decreased libido and **delayed ejaculation/anorgasmia**. This property is actually utilized therapeutically in treating premature ejaculation (e.g., Dapoxetine). **3. NEET-PG High-Yield Pearls:** * **Drug of Choice:** SSRIs are the first-line treatment for Depression, OCD, Panic Disorder, Social Phobia, and PTSD. * **Fluoxetine:** Has the longest half-life (due to its active metabolite norfluoxetine); least likely to cause withdrawal symptoms. * **Serotonin Syndrome:** A dangerous interaction when SSRIs are combined with MAO inhibitors, characterized by hyperthermia, muscle rigidity, and cardiovascular collapse. * **Discontinuation Syndrome:** Characterized by "FINISH" symptoms (Flu-like symptoms, Insomnia, Nausea, Imbalance, Sensory disturbances, Hyperarousal).

Q: Pimozide belongs to which class of drugs?

Diphenyl butyl piperidine. **Explanation:** **Pimozide** is a potent first-generation (typical) antipsychotic. Chemically, it is classified as a **Diphenyl butyl piperidine** derivative. This class is structurally related to butyrophenones but is characterized by a longer duration of action. **Why the correct option is right:** * **Diphenyl butyl piperidine:** Pimozide is the prototype of this class. Its primary mechanism of action involves the potent blockade of postsynaptic **D2 receptors**. Due to its high potency and long half-life, it is frequently used in the management of chronic schizophrenia and is the drug of choice for **Tourette’s syndrome** and **Delusional Parasitosis** (Ekbom syndrome). **Why the other options are incorrect:** * **Thiothixanthene:** This class includes drugs like **Thiothixene** and Flupentixol. They are structurally similar to phenothiazines but contain a carbon atom instead of nitrogen in the central ring. * **Phenothiazine:** This is the largest class of typical antipsychotics, further divided into Aliphatic (Chlorpromazine), Piperidine (Thioridazine), and Piperazine (Fluphenazine) subgroups. * **Butyrophenone:** This class includes **Haloperidol** and Droperidol. While diphenyl butyl piperidines are chemical derivatives of butyrophenones, they are categorized separately in pharmacological classification. **High-Yield Clinical Pearls for NEET-PG:** 1. **Specific Indication:** Pimozide is highly effective for **monosymptomatic hypochondriacal psychosis** (e.g., Delusional Parasitosis). 2. **ECG Changes:** A critical side effect of Pimozide is **QT interval prolongation**, which can lead to Torsades de Pointes; thus, baseline ECG monitoring is recommended. 3. **Potency:** It has a high extrapyramidal side effect (EPS) profile similar to Haloperidol due to its potent D2 antagonism.

Q: Which of the following is an atypical antipsychotic with the least metabolic side effects?

Ziprasidone. ***Ziprasidone*** - Among the atypical (second-generation) antipsychotics, **Ziprasidone** has the lowest risk regarding adverse **metabolic side effects**, including **weight gain**, dyslipidemia, and insulin resistance. - Due to its minimal impact on metabolic parameters, it is a preferred choice for patients with pre-existing **cardiovascular risk factors** or obesity. *Haloperidol* - Haloperidol is a **first-generation (typical)** antipsychotic, which primarily risks **extrapyramidal symptoms (EPS)** and elevated prolactin, rather than being an atypical agent. - While its metabolic risk is generally lower than high-risk atypicals (e.g., Olanzapine), it is not the correct classification for answering a question focusing on *atypical* drugs. *Risperidone* - Risperidone is an atypical antipsychotic but carries a **moderate to high risk** of causing significant **weight gain** and **hyperprolactinemia**. - Its metabolic profile is considerably worse than that of Ziprasidone or Aripiprazole. *Quetiapine* - Quetiapine carries a substantial risk profile regarding metabolic adverse effects, specifically high rates of **sedation** and clinically significant **weight gain**. - It is frequently linked to the development of **dyslipidemia** and **Type 2 diabetes mellitus**.

Q: A psychiatrist prescribes lithium for a patient who is diagnosed with bipolar disorder. Which of the following statements is incorrect regarding lithium?

Hemodialysis is not useful in lithium overdose. ***Correct Answer: Hemodialysis is not useful in lithium overdose*** - This statement is **INCORRECT** (making it the right answer to this negation question) - **Hemodialysis IS actually very useful** in severe lithium toxicity - Lithium has low molecular weight (~7 Da), minimal protein binding, and small volume of distribution, making it effectively removed by hemodialysis - **Indications for hemodialysis in lithium toxicity:** Lithium levels >4 mEq/L, severe clinical toxicity (seizures, altered consciousness), or renal failure *Incorrect Option: Lithium is teratogenic if given to pregnant females* - This statement is TRUE, so it's not the answer - Lithium causes **Ebstein's anomaly** (downward displacement of tricuspid valve) when given in first trimester - Risk is 1-2% (20x higher than general population) - FDA pregnancy category D *Incorrect Option: Lithium toxicity is exacerbated with thiazide* - This statement is TRUE, so it's not the answer - Thiazide diuretics decrease renal lithium clearance by promoting sodium depletion - This leads to **compensatory increase in proximal tubular reabsorption** of both sodium and lithium - NSAIDs and ACE inhibitors also increase lithium levels similarly *Incorrect Option: Lithium can decrease thyroid hormone levels* - This statement is TRUE, so it's not the answer - Lithium inhibits thyroid hormone synthesis and release, causing **hypothyroidism in 5-35%** of patients - Mechanism: Inhibits iodine uptake and blocks thyroid hormone release - Requires regular thyroid function monitoring (TSH, T3, T4) during lithium therapy

Q: A 35-year-old male patient presents to surgery emergency with painful erection for past 7 hours. He has a history of mood disorder and was recently prescribed a medication by treating psychiatrist. Which is the likely offending drug?

Trazodone. ***Trazodone*** - **Trazodone** is a commonly known antidepressant that can cause **priapism** as a side effect, especially at higher doses, due to its alpha-adrenergic blocking activity. [1] - The patient's presentation of a **painful erection lasting 7 hours** after starting a new psychiatric medication strongly points towards a drug-induced cause, for which trazodone is a well-established culprit. [1] *Venlafaxine* - **Venlafaxine** is an SNRI antidepressant that generally does not cause priapism as a recognized side effect. - Its adverse effect profile primarily includes nausea, insomnia, and sexual dysfunction (e.g., erectile dysfunction, anorgasmia), rather than prolonged erections. *Tianeptine* - **Tianeptine** is an atypical antidepressant that is not known to cause priapism. - It works by enhancing serotonin reuptake and is more commonly associated with side effects such as nausea, constipation, and dizziness. *Mirtazapine* - **Mirtazapine** is a tetracyclic antidepressant that works by blocking alpha-2 adrenergic receptors and certain serotonin receptors. - While it can cause sedation and weight gain, priapism is not a typical or recognized side effect of mirtazapine.

Q: Choose the correctly matched pairs regarding the drugs used in schizophrenia: 1. D2 antagonism: Reduces positive symptoms 2. 5HT2A antagonism: Reduces negative symptoms 3. 5HT1A agonism: Weight loss 4. Muscarinic antagonism: Reduces extrapyramidal symptoms

1,2. ***1,2*** - **D2 antagonism** is the primary mechanism by which antipsychotics reduce **positive symptoms** of schizophrenia, such as hallucinations and delusions. - **5HT2A antagonism** is a key mechanism of atypical antipsychotics contributing to the reduction of **negative symptoms** (e.g., apathy, anhedonia, flat affect) and cognitive deficits, while also reducing the risk of extrapyramidal symptoms. *1,2,3,4* - This option is incorrect because **5HT1A agonism** is not associated with **weight loss**. While 5HT1A partial agonism (as seen with aripiprazole and brexpiprazole) may improve negative symptoms, anxiety, and cognitive function, it does not directly cause weight loss. - Additionally, **muscarinic antagonism** does not reduce extrapyramidal symptoms as a primary mechanism. Rather, anticholinergic (muscarinic antagonist) drugs like benztropine are used to **treat** EPS after it occurs. The reduction of EPS in atypical antipsychotics primarily comes from 5HT2A antagonism and lower D2 binding affinity. *1,2,4* - This option is incorrect because **muscarinic antagonism** is not a mechanism that reduces EPS. Anticholinergic agents are used therapeutically to counteract EPS caused by dopamine blockade, but anticholinergic effects themselves do not prevent or reduce EPS. - The reduction of EPS with atypical antipsychotics is mainly due to **5HT2A antagonism** balancing dopaminergic blockade, selective limbic over striatal binding, and fast D2 dissociation kinetics. *1,4* - This option is incorrect because it omits **5HT2A antagonism**, which is crucial for reducing **negative symptoms** in schizophrenia. - It also incorrectly includes muscarinic antagonism as a mechanism that reduces EPS, when in reality anticholinergics are used to treat EPS rather than prevent it.

Q: Which of the following is true about lithium?

It can cause fine postural tremors at therapeutic dosage. ***It can cause fine postural tremors at therapeutic dosage*** - **Fine postural tremors** are a common and well-known side effect of lithium, even within its therapeutic range. - This side effect can be dose-dependent and may worsen with higher lithium concentrations. *It is also used for treatment of absence seizures* - Lithium is primarily used as a **mood stabilizer** for bipolar disorder and is not indicated for the treatment of **absence seizures**. - **Absence seizures** are typically treated with drugs like ethosuximide or valproate. *It is not teratogenic* - Lithium is known to be **teratogenic**, especially during the first trimester of pregnancy. - It is associated with an increased risk of **Ebstein's anomaly**, a congenital heart defect. *It is not absorbed from the gut* - Lithium is **rapidly and completely absorbed** from the gastrointestinal tract after oral administration. - Its absorption is not significantly affected by food, and peak plasma concentrations are usually reached within 1-3 hours.

Q: True for lithium:

Narrow therapeutic index. ***Narrow therapeutic index*** - Lithium has a **narrow therapeutic index**, meaning the difference between its effective and toxic doses is small. - This necessitates **close monitoring of serum lithium levels** to ensure efficacy and prevent toxicity. *Can be given safely in renal dysfunction* - Lithium is **primarily excreted renally**, and its clearance is directly proportional to creatinine clearance. - Therefore, it **should be used with caution** (or avoided) in patients with renal dysfunction due to increased risk of toxicity. *Protein bound* - Lithium is **not protein-bound**; it exists as a free ion in the blood. - This characteristic contributes to its rapid distribution and excretion. *Delayed absorption* - Lithium is **rapidly and almost completely absorbed** from the gastrointestinal tract. - Peak plasma concentrations are usually reached within 1-2 hours for immediate-release preparations.

Question 1

Which of the following is NOT a side effect of depression?

Accepted Answer

Flupenthixol

Answer

Propranolol

Answer

Oral contraceptives

Answer

Reserpine

Question 2

What is the half-life of lithium?

Accepted Answer

24 hours

Answer

8 hours

Answer

16 hours

Answer

36 hours

Question 3

Which of the following is NOT an adverse effect of Selective Serotonin Reuptake Inhibitors (SSRIs)?

Accepted Answer

Galactorrhea

Answer

Weight changes

Answer

Diarrhoea

Answer

Delayed ejaculation

Question 4

Pimozide belongs to which class of drugs?

Accepted Answer

Diphenyl butyl piperidine

Answer

Thiothixanthene

Answer

Phenothiazine

Answer

Butyrophenone

Question 5

Which of the following is an atypical antipsychotic with the least metabolic side effects?

Accepted Answer

Ziprasidone

Answer

Risperidone

Answer

Haloperidol

Answer

Quetiapine

Question 6

A psychiatrist prescribes lithium for a patient who is diagnosed with bipolar disorder. Which of the following statements is incorrect regarding lithium?

Accepted Answer

Hemodialysis is not useful in lithium overdose

Answer

Lithium is teratogenic if given to pregnant females

Answer

Lithium toxicity is exacerbated with thiazide

Answer

Lithium can decrease thyroid hormone levels

Question 7

A 35-year-old male patient presents to surgery emergency with painful erection for past 7 hours. He has a history of mood disorder and was recently prescribed a medication by treating psychiatrist. Which is the likely offending drug?

Accepted Answer

Trazodone

Answer

Venlafaxine

Answer

Tianeptine

Answer

Mirtazapine

Question 8

Choose the correctly matched pairs regarding the drugs used in schizophrenia:

1. D2 antagonism: Reduces positive symptoms
2. 5HT2A antagonism: Reduces negative symptoms
3. 5HT1A agonism: Weight loss
4. Muscarinic antagonism: Reduces extrapyramidal symptoms

Accepted Answer

1,2

Answer

1,4

Answer

1,2,4

Answer

1,2,3,4

Question 9

Which of the following is true about lithium?

Accepted Answer

It can cause fine postural tremors at therapeutic dosage

Answer

It is also used for treatment of absence seizures

Answer

It is not teratogenic

Answer

It is not absorbed from the gut

Question 10

True for lithium:

Accepted Answer

Narrow therapeutic index

Answer

Can be given safely in renal dysfunction

Answer

Protein bound

Answer

Delayed absorption

Drugs in Psychiatric Disorders — MCQs

Drugs in Psychiatric Disorders — MCQs

On this page

Practice by Chapter

Want unlimited practice?