Last edited 04/2020

Excessive daytime sleepiness (EDS) is best described as an urge to sleep during daytime hours

  • this is a common problem
    • occurs for at least three days a week in 4-20% of the population
    • affects quality of life, workplace performance, and has safety implications, for example, when driving

Prompt diagnosis is important because effective therapeutic strategies are available for many causes of excessive daytime sleepiness. In some cases treatment may not only improve quality of life but also reduce mortality.


  • key to accurate diagnosis is differentiating excessive daytime sleepiness (EDS) from symptoms of fatigue or being “tired all the time”

  • the Epworth Sleepiness Scale (ESS) score is a useful way to assess and classify EDS
    • ESS >10 indicates EDS and >17 indicates severe EDS

  • commonest causes of EDS include:
    • obstructive sleep apnoea, periodic limb movement syndrome, narcolepsy, and circadian rhythms

  • treatment of obstructive sleep apnoea
    • reduces excessive daytime sleepiness
    • improves neuropsychological function
    • reduces blood pressure

  • referral is indicated for patients with EDS
    • for assessment, including overnight sleep study


  • Drug and Therapeutics Bulletin (2004); 42(7): 52-6.
  • Brown J, Makker KM. An approach to excessive daytime sleepiness in adults. BMJ 2020;368:m1047
  • .