Neurobiology and Genetics of Mental Disorders Practice Questions

Q: Amnestic syndrome is characterized by all of the following except?

Intact memory. **Explanation:** Amnestic syndrome (most commonly encountered as **Wernicke-Korsakoff Syndrome** in psychiatry) is a focal cognitive impairment characterized by a profound deficit in memory, while other cognitive functions remain relatively preserved. **Why "Intact Memory" is the correct answer:** By definition, the hallmark of amnestic syndrome is **impaired memory**. It specifically involves an inability to form new memories (**anterograde amnesia**) and difficulty recalling past events (**retrograde amnesia**). Since the question asks for the "except" option, "Intact memory" is the right choice as it contradicts the core pathology of the disorder. **Analysis of incorrect options:** * **A. No disturbance of consciousness:** Unlike Delirium, patients with amnestic syndrome are alert and awake. Their level of consciousness is not clouded. * **B. Attention is intact:** Patients can usually focus on immediate tasks. The deficit is in the *encoding and retrieval* of information, not the initial registration or attention. * **C. Intact intellect:** General intelligence (IQ), reasoning, and personality remain largely preserved, distinguishing it from Dementia, where global cognitive decline occurs. **NEET-PG High-Yield Pearls:** 1. **Confabulation:** A classic feature where patients fill memory gaps with fabricated stories (common in Korsakoff’s). 2. **Neuroanatomy:** The primary lesions are found in the **mammillary bodies** and the **dorsomedial nucleus of the thalamus**. 3. **Etiology:** Most commonly due to **Thiamine (Vitamin B1) deficiency** secondary to chronic alcohol use. 4. **Differentiating Point:** Amnestic syndrome = Isolated memory loss; Dementia = Global cognitive decline; Delirium = Clouding of consciousness.

Q: General Paresis of the Insane is associated with which condition?

Tertiary Syphilis. **Explanation:** **General Paresis of the Insane (GPI)**, also known as paretic neurosyphilis, is a chronic meningoencephalitis caused by the direct invasion of the brain parenchyma by *Treponema pallidum*. It is a late-stage manifestation of **Tertiary Syphilis**, typically occurring 10–25 years after the initial infection. **Why Tertiary Syphilis is correct:** GPI is characterized by a "constellation of neuropsychiatric symptoms." Clinically, it presents with the **"4 Ps"**: **P**ersonality changes, **P**aresis (weakness), **P**upillary abnormalities (Argyll Robertson pupil), and **P**sychosis (classically **grandiose delusions**). It leads to progressive cognitive decline and frontal lobe syndrome. **Why other options are incorrect:** * **Miliary Tuberculosis:** While TB can cause meningitis or tuberculomas, it does not lead to the specific parenchymal degenerative pattern seen in GPI. * **Vitamin B12 Deficiency:** This causes Subacute Combined Degeneration (SCD) of the spinal cord and "megaloblastic madness" (psychosis/dementia), but it is a nutritional deficiency, not an infectious process. * **Autoimmune Encephalitis:** Conditions like Anti-NMDA receptor encephalitis present with acute psychosis and seizures, but they are mediated by antibodies rather than treponemal infection. **High-Yield Clinical Pearls for NEET-PG:** * **Argyll Robertson Pupil:** The classic sign in neurosyphilis—pupils accommodate but do not react to light ("Prostitute’s Pupil"). * **Diagnosis:** CSF-VDRL is highly specific (though less sensitive); FTA-ABS is often used for confirmation. * **Treatment:** Intravenous Penicillin G is the gold standard. * **Historical Note:** GPI was one of the first psychiatric conditions for which a biological cause was identified.

Q: All of the following are true about Kluver-Bucy syndrome except?

Hyperactivity. **Kluver-Bucy Syndrome (KBS)** is a clinical triad of behavioral changes resulting from **bilateral lesions of the anterior temporal lobes**, specifically involving the **amygdala**. ### Why "Hyperactivity" is the Correct Answer (The Exception) In Kluver-Bucy syndrome, patients typically exhibit **placidity** (a marked decrease in aggression and fear) rather than hyperactivity. While they may constantly explore their environment (hypermetamorphosis), they lack the increased psychomotor speed or agitation associated with hyperactivity. In fact, the syndrome is characterized by a "taming" effect where previously wild or aggressive subjects become docile. ### Explanation of Other Options * **Hypersexuality (A):** Patients show a marked increase in sexual libido, often directed toward inappropriate objects (paraphilias) or species. * **Hypermetamorphosis (C):** This refers to an irresistible impulse to notice and react to every visual stimulus, leading to the compulsive exploration of objects. * **Placidity (D):** This is a hallmark feature. The destruction of the amygdala leads to a loss of the "fear response," resulting in a lack of emotional reactivity and anger. ### High-Yield Clinical Pearls for NEET-PG * **Core Features (The 6 'H's):** 1. **Hypersexuality** 2. **Hypermetamorphosis** (Compulsive exploration) 3. **Hyperorality** (Tendency to examine objects by mouth) 4. **Hyperphagia** (Bulimia/Overeating) 5. **Hypo-emotionality** (Placidity/Docility) 6. **Visual Agnosia** (Psychic blindness – inability to recognize objects visually). * **Anatomical Site:** Bilateral Amygdala (Temporal Lobe). * **Common Causes:** Herpes Simplex Encephalitis (most common), Head Trauma, Pick’s Disease, and Stroke. * **Key Distinction:** Do not confuse Hypermetamorphosis with Hyperactivity; the former is a sensory-driven compulsion to touch, while the latter is a motor-driven state.

Q: Which chromosome is associated with bipolar disease?

Chromosome 18. ### Explanation **Correct Option: C (Chromosome 18)** Bipolar Disorder (BD) is a highly heritable psychiatric condition with a complex polygenic inheritance pattern. Extensive linkage studies and genome-wide association studies (GWAS) have consistently identified **Chromosome 18** (specifically regions 18p and 18q) as a major susceptibility locus. It is considered one of the most replicated findings in the genetics of bipolar disorder, particularly linked to Bipolar I subtype. **Analysis of Incorrect Options:** * **Option A: Chromosome 16:** While some studies suggest a minor link to Chromosome 16 in general psychiatric vulnerability, it is not a primary or classic association for Bipolar Disorder. * **Option B: Chromosome 13:** Chromosome 13 (specifically 13q) is more strongly associated with **Schizophrenia** (linked to the *G72/DAOA* gene) rather than being the primary marker for Bipolar Disorder. * **Option D: Chromosome 11:** Chromosome 11 contains the gene for Tyrosine Hydroxylase and has been studied in relation to Bipolar Disorder, but the evidence for Chromosome 18 is statistically more robust and frequently tested in exams. **High-Yield Clinical Pearls for NEET-PG:** * **Other Associated Chromosomes:** Besides 18, Chromosomes **21q** and **22q** (DiGeorge syndrome region) are also frequently implicated in Bipolar Disorder. * **Genetics:** The risk of BD in a child with one affected parent is ~10-25%; if both parents are affected, the risk rises to ~50-75%. * **Monozygotic Twins:** The concordance rate for Bipolar Disorder in identical twins is high, ranging from **40% to 70%**. * **Key Gene:** The *ANK3* (Ankyrin G) and *CACNA1C* (Calcium channel) genes are modern high-yield genetic associations found in GWAS for Bipolar Disorder.

Q: Which of the following is NOT seen in organic psychosis?

Normal common knowledge. **Explanation:** Organic psychosis (now often categorized under Delirium or Neurocognitive Disorders) is characterized by an underlying physical, systemic, or neurological etiology. The hallmark of organic brain syndromes is the impairment of **cognitive functions**, which distinguishes them from functional psychoses like Schizophrenia. **Why "Normal common knowledge" is the correct answer:** In organic psychosis, there is a global impairment of cognitive functions. This includes deficits in memory, orientation, and **general fund of information (common knowledge)**. A patient with organic psychosis will typically struggle with basic facts they previously knew (e.g., naming the current Prime Minister or simple arithmetic) due to cognitive decline or acute confusion. Therefore, "Normal common knowledge" is **not** seen; rather, it is impaired. **Analysis of Incorrect Options:** * **A & B (Disorientation and Clouding of Consciousness):** These are the cardinal features of organic psychosis (specifically Delirium). Unlike functional psychosis, where a patient is usually alert and oriented, organic cases show a fluctuating level of consciousness and inability to identify time, place, or person. * **C (Hallucinations):** These are common in both organic and functional psychosis. However, in organic states, **visual hallucinations** are more frequent than auditory ones (the reverse is true for Schizophrenia). **NEET-PG High-Yield Pearls:** * **Visual Hallucinations + Disorientation =** Think Organic (Delirium/Alcohol Withdrawal). * **Auditory Hallucinations + Clear Sensorium =** Think Functional (Schizophrenia). * **Tactile Hallucinations:** Highly suggestive of Cocaine use (Magnan’s symptoms) or Delirium Tremens. * **EEG in Organic Psychosis:** Usually shows generalized slowing (except in Delirium Tremens, where it shows low-voltage fast activity).

Question 1

Amnestic syndrome is characterized by all of the following except?

Accepted Answer

Intact memory

Answer

No disturbance of consciousness

Answer

Attention is intact

Answer

Intact intellect

Question 2

General Paresis of the Insane is associated with which condition?

Accepted Answer

Tertiary Syphilis

Answer

Miliary tuberculosis

Answer

Vitamin B12 deficiency

Answer

Autoimmune encephalitis

Question 3

All of the following are true about Kluver-Bucy syndrome except?

Accepted Answer

Hyperactivity

Answer

Hypersexuality

Answer

Hypermetamorphosis

Answer

Placidity

Question 4

Which of the following features is more suggestive of organic conditions?

Accepted Answer

Visual hallucinations

Answer

Primary delusions

Answer

Made phenomena

Answer

Third person auditory hallucinations

Question 5

Reduction in central _____ plays a vital role in suicidal behavior.

Accepted Answer

Serotonin

Answer

Dopamine

Answer

Acetylcholine

Answer

Epinephrine

Question 6

Acute uraemic syndrome causes disturbance in which of the following?

Accepted Answer

Consciousness

Answer

Affect

Answer

Thought

Answer

Memory

Question 7

Which chromosome is associated with bipolar disease?

Accepted Answer

Chromosome 18

Answer

Chromosome 16

Answer

Chromosome 13

Answer

Chromosome 11

Question 8

Which of the following neurotransmitters is most consistently associated with an increased risk of suicide?

Accepted Answer

Serotonin

Answer

Noradrenaline

Answer

GABA

Answer

Dopamine

Question 9

Which of the following is NOT seen in organic psychosis?

Accepted Answer

Normal common knowledge

Answer

Disorientation in place, time, and person

Answer

Clouding of consciousness

Answer

Hallucinations

Question 10

Which neurotransmitter changes are proposed in cases of anxiety?

Accepted Answer

Increased norepinephrine, and decreased GABA and serotonin

Answer

Decreased norepinephrine and serotonin, and increased acetylcholine

Answer

Decreased GABA and acetylcholine

Answer

Increased serotonin, and decreased norepinephrine and GABA

Neurobiology and Genetics of Mental Disorders — MCQs

Neurobiology and Genetics of Mental Disorders — MCQs

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