Neurobiology and Genetics of Mental Disorders — MCQs

Q: What is the term used in neuropsychology to describe the phenomenon where an individual persistently and inappropriately repeats the same thoughts or actions?

Perseveration. ***Perseveration, characterized by repetitive and inappropriate thoughts or actions.*** - **Perseveration** is a core executive dysfunction symptom, where an individual repeatedly responds with the same answer or behavior despite changing situations or instructions. - It often indicates **frontal lobe dysfunction** due to conditions like stroke, traumatic brain injury, or neurodegenerative diseases. *Thought blocking, commonly seen in schizophrenia.* - **Thought blocking** refers to an abrupt interruption in the flow of thoughts, where the person stops speaking mid-sentence and then, after a brief pause, cannot recall what they were saying. - It is a **thought disorder** symptom associated with conditions like **schizophrenia**, not persistent repetition. *Obsessions, a hallmark of obsessive-compulsive disorder (OCD).* - **Obsessions** are intrusive, unwanted, and recurrent thoughts, images, or urges that cause distress and anxiety, but they are typically *internal mental experiences* rather than repetitive outward actions in this context. - While they are repetitive, they are specifically linked to the **anxiety-driven cycle of OCD** and are distinct from the executive dysfunction seen in perseveration. *Rumination, often associated with mood disorders.* - **Rumination** involves repetitive and passive dwelling on the causes, meanings, and consequences of negative thoughts and feelings, often seen in **depression**. - It is a **cognitive process** focused on internal contemplation of distress, rather than a motor or behavioral repetition in response to a task.

Q: Which of the following neurotransmitters is NOT suspected to be involved in the pathophysiology of schizophrenia?

Ascorbic acid. ***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.

Neurobiology and Genetics of Mental Disorders — MCQs

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Neuroanatomy for Psychiatry

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Neurotransmitters and Receptors

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Neuroimaging in Psychiatry

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Neuropsychological Assessment

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Genetics of Psychiatric Disorders

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Epigenetics in Psychiatry

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Psychoneuroimmunology

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Circadian Rhythms and Psychiatry

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Neurodevelopmental Perspectives

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Stress and HPA Axis

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Gene-Environment Interactions

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Biomarkers in Psychiatry

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