Excessive sleepiness and hypersomnias
Kleine-Levin Syndrome
A rare disorder with recurring episodes of extreme sleepiness lasting days to weeks, with changes in thinking and behaviour, and normal health between episodes.
Overview
Kleine-Levin syndrome (KLS) is a rare neurological disorder that causes recurring episodes of excessive sleep, sometimes up to 20 hours a day, along with cognitive and behavioural changes. Each episode lasts days to weeks, and between episodes people are typically entirely normal.
During episodes, people may feel unreal or detached (derealisation), confused, apathetic or childlike, and some have increased appetite or hypersexual behaviour. KLS most often begins in adolescence and affects males more than females.
Episodes often become less frequent and milder over years and usually stop eventually, although the course varies. Because KLS is rare, diagnosis typically involves a specialist and careful exclusion of other conditions.
KLS is estimated to affect about one to five people per million.
Common symptoms
- Recurrent episodes of excessive sleep lasting days to weeks
- Confusion, poor concentration and memory gaps
- A dreamlike feeling of unreality (derealisation)
- Apathy and childlike behaviour
- Increased appetite or binge eating in some people
- Hypersexual behaviour in some people
- Normal sleep, mood and behaviour between episodes
Causes and risk factors
- Cause unknown
- Episodes often triggered by infection, alcohol, sleep deprivation or stress
- More common in adolescent males
- Possible genetic and immune factors under study
How it is diagnosed
Diagnosis is clinical, based on recurrent episodes of severe sleepiness lasting at least two days, with at least one cognitive or behavioural change during episodes, and normal function between them. Clinicians also exclude other causes such as epilepsy, psychiatric conditions, brain injury and metabolic disorders, using tests such as brain imaging, EEG and blood tests where needed.
Treatment options
Supportive care at home during episodes
Keeping the person safe and comfortable is the main approach.
Lithium
Some specialists prescribe lithium to reduce episode frequency, though evidence is limited.
Stimulants
These may reduce sleepiness during episodes but do not treat the cognitive symptoms.
Avoiding triggers
Reducing alcohol, sleep deprivation and infection risk may help reduce episodes.
What you can do yourself
- Keep a diary of episodes and possible triggers
- Ensure supervision and safety during episodes, including no driving
- Arrange school or work flexibility in advance
- Avoid alcohol and get vaccinations recommended by your clinician to reduce infections
When to see a doctor
- A teenager has repeated episodes of sleeping most of the day with confusion or unusual behaviour
- Episodes include severe confusion, aggression or risky behaviour
- Low mood or suicidal thoughts appear between episodes
- Episodes are increasing in frequency
Frequently asked questions
Why is KLS called sleeping beauty syndrome?
The nickname refers to long periods of sleep during episodes. It is a serious medical condition, and episodes also involve confusion and behavioural changes, not just sleeping.
Does KLS go away?
In many people episodes become less frequent and milder over time and eventually stop, often over years. The course varies widely between individuals.
Can KLS be cured?
There is no cure. Treatment focuses on safety during episodes, and some medicines such as lithium may reduce episodes for some people.
What triggers an episode?
Infections are the most common reported trigger, along with alcohol, sleep deprivation and stress. Many episodes have no clear trigger.
Sources
This page is general information, not a diagnosis or medical advice. Read our medical disclaimer.