Intended for healthcare professionals

Clinical Review

Narcolepsy and excessive daytime sleepiness

BMJ 2004; 329 doi: (Published 23 September 2004) Cite this as: BMJ 2004;329:724
  1. Adam Zeman, consultant neurologist (,
  2. Tom Britton, consultant neurologist2,
  3. Neil Douglas, professor of respiratory and sleep medicine3,
  4. Andrew Hansen, general practitioner4,
  5. Jane Hicks, specialist registrar in neuropsychiatry5,
  6. Robin Howard, consultant neurologist6,
  7. Andrew Meredith, consultant ENT surgeon7,
  8. Ian Smith, consultant physician8,
  9. Gregory Stores, emeritus professor of developmental neuropsychiatry9,
  10. Sue Wilson, psychopharmacology research fellow,
  11. Zenobia Zaiwalla, consultant in clinical neurophysiology
  1. 1 Western General Hospital, Edinburgh EH4 1PU
  2. 2 King's College Hospital, London
  3. 3 Royal Infirmary, Edinburgh
  4. 4 Ridge Medical Centre, Bradford
  5. 5 Burden Centre, Frenchay Hospital, Bristol
  6. 6 National Hospital for Neurology and Neurosurgery, London
  7. 7 Conquest Hospital, St Leonards-on-Sea, East Sussex
  8. 8 Respiratory Support and Sleep Centre, Papworth Hospital, Cambridge
  9. 9 University of Oxford, Oxford
  10. 10 University of Bristol, Bristol
  11. 11 Park Hospital and Radcliffe Infirmary, Oxford
  1. Correspondence to: A Zeman
  • Accepted 15 July 2004


Excessive daytime sleepiness is common,1 yet opportunities to learn about sleep medicine in medical school are rare; a survey in 1998 indicated that undergraduate courses devoted a median of five minutes to sleep and its disorders.2 In this review we provide an update on the biology, diagnosis, and management of narcolepsy—an important, yet often misdiagnosed, cause of sleepiness that has seen exciting recent advances. We also briefly outline the other principal causes of daytime sleepiness and aim to equip the general reader with a practical approach to the assessment of patients who complain of excessive daytime sleepiness.

Sources and selection criteria

This paper is based on a literature search conducted to produce evidence based guidelines on the diagnosis and management of narcolepsy in adults and children.3 We searched Medline, Embase, the Cochrane Collaboration, and two specialist sleep literature resources for abstracts with the key word “narcolepsy.” We read the full text of relevant papers and hand searched these for other relevant material. A multidisciplinary working party prepared the guidelines, and a group of 10 independent experts later reviewed them. These guidelines can be downloaded from the news section of (accessed July 2004).

Clinical features of narcolepsy

Narcolepsy is a chronic neurological disorder affecting sleep regulation and causing excessive sleepiness and, in most cases, cataplexy (brief attacks of weakness on emotional arousal).3 4 The excessive sleepiness of narcolepsy comprises both a background feeling of sleepiness present much of the time and a strong, sometime irresistible, urge to sleep recurring at intervals through the day. This desire is heightened by conducive, monotonous circumstances, but naps at inappropriate times—such as during meals—are characteristic. The naps of narcolepsy usually last from minutes to an hour and occur a few times each day. Cataplexy refers to partial or generalised, almost invariably bilateral, loss of skeletal muscle tone and …

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