Johns Hopkins Psychiatry Guide

Narcolepsy

John W. Dougherty, III , D.O., David Neubauer, M.D.
Narcolepsy is a topic covered in the Johns Hopkins Psychiatry Guide.

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DEFINITION

  • Narcolepsy is characterized by impaired sleep and wakefulness, along with rapid eye movement (REM) sleep abnormalities.
  • The clinical tetrad includes the following, although only 10% of those affected will have all 4 symptoms:
    • Excessive daytime sleepiness
    • Hallucinations occurring at the transition from wakefulness to sleep (hypnagogic)
    • Sleep paralysis
    • Cataplexy
  • Disrupted nighttime sleep is common, but the most disabling symptoms are daytime inattention and hypersomnolence.
    • Especially during sedentary activities
    • Sometimes with irrepressible sleep attacks
  • Cataplexy is a brief (usually less than 2 minutes) symmetrical sudden loss of muscle tone with preserved consciousness, typically precipitated by strong emotions (especially laughter).
    • Episodes may range from very subtle (e.g., neck or jaw weakness) to complete collapse.
  • Type 1 narcolepsy requires the presence of cataplexy or decreased CSF hypocretin (orexin) levels.
  • Type 2 narcolepsy involves abnormalities evident upon nighttime and daytime sleep laboratory testing.
  • Narcolepsy is classified under the Sleep-Wake Disorders section of the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5)[1].

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Last updated: October 17, 2014