Kleine–Levin Syndrome (KLS)

Kleine–Levin Syndrome (KLS) is a rare neuropsychiatric disorder characterized by persistent episodic hypersomnia, hyperphagia, cognitive impairment, and mood changes. Individuals can also experience hypersexuality, personality changes, and behavioural changes.

  • The prevalence of KLS is thought to be extremely rare, perhaps 1 in 1 million.
Risk Factors
  • Adolescent males are at the greatest risk, and is much more common in males than females.
  • Individuals typically present with recurrent episodes of hypersomnia, sleeping up to 18 hours per day.
    • These episodes can last between days to weeks, and can occur between one to ten times per year.
    • During these episodes, individuals typically also have hyperphagia and hypersexuality.
    • Confusion, irritability, aggression, and hallucinations can also occur during these episodes.
  • In between these episodes, individuals with have normal sleep and behaviours
  • The average duration of these episodes is about 4 years.
For Patients
For Providers