Epidemiology

  • Incidence: 0.70 cases per 100,000 person-years
  • Peak incidence: 20-30 years
  • Sex ratio: 1:1
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Clinical features

Symptoms
  • Excessive daytime sleepiness (80%)
  • Lethargy (70%): Some patients with narcolepsy will have chronic daily sleepiness as the sole symptom
  • Limb weakness (unilateral) (40%)
  • Hallucinations (30%): Hypnagogic hallucinations are vivid visual, tactile, or auditory hallucinations that can occur when a patient is falling asleep.
  • Syncope (20%): Whilst narcolepsy doesn't cause a loss of consciousness, patients may describe themselves as having episodes of 'collapse'.