Sleep disorders: narcolepsy: practice question

A Psychiatry question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Psychiatry · Sleep disorders: narcolepsy

Sample item

A 20-year-old has irresistible daytime sleep attacks, sudden loss of muscle tone on laughing, sleep paralysis and hypnagogic hallucinations. The underlying defect is loss of:

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Hypocretin (orexin)-producing neurons

Narcolepsy type 1 involves loss of hypothalamic hypocretin neurons, with HLA-DQB1*06:02 association, cataplexy and REM intrusion phenomena. Modafinil treats sleepiness, and sodium oxybate or SSRIs treat cataplexy.

Option by option

  • A. Cholinergic neurons of the basal forebrain

    Loss of basal forebrain cholinergic neurons is seen in Alzheimer disease.

  • B. Hypocretin (orexin)-producing neurons (correct)

    Correct. Loss of hypocretin neurons underlies narcolepsy with cataplexy.

  • C. Dopamine neurons in the substantia nigra

    Loss of nigral dopamine neurons causes Parkinson disease.

  • D. Serotonin neurons of the raphe

    Raphe serotonin neurons are not the primary defect.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Psychiatry question

What is the answer to this Psychiatry question?

The best answer is B, Hypocretin (orexin)-producing neurons. Narcolepsy type 1 involves loss of hypothalamic hypocretin neurons, with HLA-DQB1*06:02 association, cataplexy and REM intrusion phenomena.

Why is "Cholinergic neurons of the basal forebrain" not the answer?

Loss of basal forebrain cholinergic neurons is seen in Alzheimer disease.

Why is "Dopamine neurons in the substantia nigra" not the answer?

Loss of nigral dopamine neurons causes Parkinson disease.

Why is "Serotonin neurons of the raphe" not the answer?

Raphe serotonin neurons are not the primary defect.

What concept does this question test?

It tests Sleep disorders: narcolepsy in Psychiatry. Modafinil treats sleepiness, and sodium oxybate or SSRIs treat cataplexy.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Sleep disorders: narcolepsy?

Learn each diagnosis by its core features and its first-line treatment. Then use the flashcards and the other Psychiatry questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.