What is ‘sleeping beauty syndrome'? Extremely rare condition makes people sleep 16 to 20 hours

New York Post

28-07-2025

It's not such a fairy tale.
With stress, smartphones, and bad nighttime habits, many of us are struggling to get the recommended six to nine hours of sleep each night.
However, a rare condition causes some to doze for nearly an entire day for days on end.
4 A rare condition called 'sleeping beauty syndrome' causes some to doze for nearly an entire day for days on end.
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What is sleeping beauty syndrome?
Kleine-Levin syndrome (KLS), also known as 'Sleeping beauty syndrome' or 'familial hibernation syndrome,' is a neurological disorder that causes sufferers to sleep for extended periods, as much as 16 to 20 hours a day.
An ultra-rare condition, research suggests KLS occurs in one to five people per million and has a higher prevalence among Ashkenazi Jews.
To date, only 500 cases have been reported in medical journals.
While 70 percent of people with this disorder are male, KLS can affect either sex, with symptoms typically emerging in early adolescence and progressing for an average of 14 years.
KLS is a central disorder of hypersomnolence, a category which also includes narcolepsy. Episodes can appear and subside, with most patients experience it for 10 to 20 years.
Symptoms of KLS or sleeping beauty syndrome
A KLS episode is defined as symptoms that persist for at least two days. Episodes average around 10 days but can last for several weeks.
For one patient with KLS, her sleep count reached 70 consecutive days.
4 Episodes average around 10 days but can last for several weeks.
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Those with Kleine-Levin sometimes display ferocious hunger, hallucinate and become unprecedentedly aroused during episodes, according to the Kleine-Levin Syndrome Foundation.
Experts say the majority of people diagnosed with KLS will experience on average, 20 episodes in their lifetime.
Symptoms of KLS include:
Extreme drowsiness and inability to stay awake.
Increased appetite
Weight gain
Increased sex drive
Hallucinations
Behavioral changes, including irritability and disorientation
Anxiety or depression.
Confusion or amnesia.
KLS episodes can come on suddenly, increasing the likelihood of injury if the patient is operating a motor vehicle or machinery — so people with the condition are advice to stay home in a secure environment during episodes.
4 The exact cause of KLS is unknown, although researchers suggest that it may be genetic or the result of an illness or injury that damages the hypothalamus.
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What causes KLS?
The exact cause is unknown, although researchers suggest that it may be genetic or the result of an illness or injury that damages the hypothalamus, the part of the brain responsible for regulating sleep.
There is speculation that the disorder, which often develops after people become symptomatic for an infectious disease, is an autoimmune reaction in which the body mistakes brain tissue for an invader, according to a 2005 study.
KLS can be triggered by:
Infection
Substance use
Head trauma
Physical exertion
Stress
Memory recall during an episode is limited. Patients may be able to eat and use the bathroom, but as a consequence of their extreme exhaustion, they struggle with physical function beyond these basic behaviors.
4 Therapy is often recommended alongside other KLS treatments to help patients manage symptoms of hypersexuality, anxiety, and depression.
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'When it comes to relationships with friends, family, school is a big one: I lose everything when I'm in an episode,' one KLS patient previously shared.
After an episode, normal behavior and sleep routines resumes.
KLS treatment
Treatment for KLS includes medications like lithium, IV steroids, and/or stimulants to reduce episode frequency, length, and severity.
Therapy is often recommended alongside these treatments to help patients manage symptoms of hypersexuality, anxiety and depression.