Kleine-Levin Syndrome


kleine-levin Syndrome is characterized by people sleeping for very long periods of time

Kleine-Levin Syndrome is a rare sleep disorder, with the main feature being that people spend exceptionally long periods of time asleep.

They often only wake to eat or use the bathroom, and even when awake aren’t really alert. It’s sometimes called sleeping beauty syndrome, but it’s unlikely that those who have it would see it so romantically.

If you, or someone you know, are one of the very few people who have Kleine-Levin Syndrome, then you may well be frustrated by the lack of information about it.

This article may not answer all of your questions, but hopefully it will give you a solid overview, and some useful information you may not have heard before.

You’ll find out exactly what Kleine-Levin Syndrome is, how rare it is and what the symptoms are. I’ll also cover the limited theories of possible causes, as well as treatment options.

How long do people with Kleine-Levin sleep for?

During an episode, people with Kleine-Levin Syndrome might sleep for up to 20 hours every day. These sleep episodes can last for a few days, weeks or even months.

There may be days, weeks, months or even years between each episode. And people may suffer from the disorder for many years, perhaps as many as 10-12 years.

In medical terms it may also be seen as a case of recurrent hypersomnia. Although in simple terms, hypersomnia is more about feeling tired, sleepy and falling asleep during the day.

People who have hypersomnia may sleep for many hours at night, and possibly have long naps during the day. They may also find themselves falling asleep at various points during the day. Those with Kleine-Levin Syndrome, however, will stay asleep virtually all day.

How many people have it?

It’s estimated that about 1 person in a million suffers from Kleine-Levin Syndrome. This could mean just a few hundred people in the USA, for example.

It’s more common in men (70%-90% of cases). It more commonly starts in adolescence, although it can occur at any time in your life. There may also be a genetic aspect, as there appears to be a higher rate of Jewish boys who suffer from the condition.

It’s so rare that it’s unlikely your doctor will have come across it before. Judging by some individual stories, this can result in either misdiagnosis or a frustrating process of establishing the correct diagnosis.

As it often starts during teenage years, an initial impression may be formed that it might just be normal teenager behavior. But if you look closely at teenager sleep patterns, you’ll find that this syndrome isn’t at all normal for teenagers.

The other challenge is the lack of large-scale research into the disorder. More common sleep disorders can have medical trials based on hundreds or even thousands of people with the problem.

For Kleine-Levin Syndrome, however, most of the limited research is based on either individual case studies or small scale programs. And unsurprisingly, nearly every research paper ends by saying further research or larger scale trials are needed before definitive conclusions can be reached.


The primary symptom is the need to sleep for 16 to 18 hours every day, over extended periods lasting for days or weeks.

According to the international classification of sleep disorders published in 2014, a typical episode lasts for 10 days on average. Furthermore, these sleep episodes aren’t isolated events, but usually reoccur at least once a year.

They generally start without any warning, although in some cases you might experience flu like symptoms at the onset.

Other common symptoms include:

  • Excessive appetite and eating. You may feel an overwhelming urge to eat anything available, often resulting in weight gain.
  • Disorientation. People report that they feel vague, dream-like, confused or disorientated when awake. You may also suffer from audio or visual hallucinations. Parents, friends, colleagues and caregivers may find your behavior childish, immature or confusing. They may also think you show signs of irritability, lethargy and apathy.
  • Abnormal speech. Your speech may be affected, resulting in slurred or child-like speech.
  • Hyper-sexuality. You may find that you have an abnormally high and uninhibited sexual drive during an episode.
  • Mood changes. You may feel depressed, irritable or moody during and between episodes. It’s believed that this is a result of the disorder and not a cause.
  • Amnesia. You may not be able to remember everything that you do during one of the sleep episodes.

Early thinking was that most of these symptoms were experienced by people with Kleine-Levin Syndrome and this may have influenced medical diagnosis.

However, more recent studies suggest that these other symptoms may not be present in all cases. For example, one small survey found that 75% of people may experience excessive eating and only about 50% the hyper-sexuality symptom.


There are very few theories about the likely causes of Kleine-Levin Syndrome. One theory, which has some expert support, is that it might be caused by a malfunction of the hypothalamus and/or thalamus parts of the brain.

These areas govern appetite and sleep, which matches the sleep problem and the related symptom of excessive eating. But as mentioned earlier, the rarity of the disorder means there’s limited research being carried out to try and truly identify the causes.

A 2004 study reviewing previous research reported that 89% of patients remembered an illness or activity which happened just prior to suffering the first episode. This included the events listed below.

The figures in brackets are the percentage of those surveyed who reported each of these events, with some people recalling more than one event.

  • Infections (72%, with 25% reporting having flu or cold-like symptoms, including a fever).
  • Alcohol use (23%)
  • Sleep deprivation (22%)
  • Unusual stress (20%)
  • Physical exertion (19%)
  • Traveling (10%)
  • Head injury (9%)
  • Marijuana use (6%)

There appears to be wider support to the theory that some form of infection before the first occurrence of a sleep episode is one of the most likely causes.

The difficulty of getting a diagnosis

Kleine-Levin Syndrome is a difficult sleep disorder to diagnose. It’s usually the case that other possible explanations for your symptoms are first excluded, and then the diagnosis may be reached.

Your doctor needs to carefully consider your case history and symptoms to eliminate other medical conditions and sleep disorders. For example, narcolepsy, general hypersomnia, epilepsy, mental disorders such as bipolar disorder and depression, and drug or alcohol use.

For this reason most diagnoses of Kleine-Levin Syndrome will only really be confirmed after a second episode of prolonged sleep. And frustratingly, it can take a long time to receive a diagnosis.

Some research has been undertaken to see if other modern techniques, such as MRI scans, can help diagnoses. But even these haven’t proven conclusive.

For example, a Swedish study used single photon emission computed tomography to look at the brains of 24 people with Kleine-Levin Syndrome.

Although 48% showed anomalies, the others didn’t. So the researchers couldn’t recommend this as a definite method for diagnosing the condition, though it might still provide another clue for doctors.

Furthermore, people with this disorder can appear completely normal between episodes, making a diagnosis even harder to come to.


Unfortunately, there don’t really appear to be any effective treatments for Kleine-Levin Syndrome. Moreover, any suggested treatments are only supported by very limited trials. Two possibilities are:

1) Lithium

A trial involving just three people suggested that taking Lithium as a medication may reduce the length and frequency of the sleep episodes. It can also reduce significantly the other behavioral symptoms.

However, it doesn’t seem to prevent the occurrence of the sleep episodes, so it’s not a cure. The researchers concluded:

…in KLS with a high frequency of episodes and severe behavioral changes lithium may become a treatment option.” 

2) Stimulants

Stimulant pills, including amphetamines, methylphenidate and modafinil, are sometimes prescribed to counteract the sleepiness. However, they may increase irritability and won’t improve the disorientation people might feel. Furthermore, they don’t seem to have any effect on the underlying sleep problem.

In general, your doctor may advise that you don’t need to be cared for in hospital and home care is the best option. Parents, friends and caregivers may need to support and encourage you during the prolonged sleep episodes.

It’s recommended that your support network should also encourage you to maintain good sleep hygiene. In particular, encouraging you to try and maintain stable sleep patterns – as much as is possible considering the nature of the sleep disorder.

They may also need to ensure you’re not at risk by undertaking dangerous activities such as driving when awake.

Waking someone up

It may be possible to wake people up during a sleep episode. However, they are still likely to suffer the confused, irritable, childlike and vague symptoms mentioned above.

Even when awake, they may not be able to do much except the essentials of eating and using the bathroom. Certainly working or going to college wouldn’t seem possible.


Kleine-Levin Syndrome is an exceptionally rare sleep disorder. For example, it probably only affects a few hundred people in the whole of the United States.

The main symptom is sleeping for long periods of up to 20 hours a day, with repeat episodes of the sleep periods. Your life is effectively put on hold during the prolonged sleep episodes, as you’re unlikely to be able to work, socialize or study.

There are a range of other symptoms that you may experience, including overeating, childlike behavior and disorientation. It may also have a significant impact on your mood and general well-being.

The causes haven’t really been established, though some form of infection before suffering the first sleep episode does appear to be fairly common.

There are no known cures. In very limited trials the use of Lithium as a medication does seem to help reduce the frequency and severity of the symptoms, but it’s not a cure.

Being cared for at home is normally the recommended approach.

Your view and experience

Do you, or anyone you know, suffer from Kleine-Levin? How does it affect your life, and is there anything which helps you manage the sleep disorder and its impact on your life?

Feel free to leave a comment below to share your story and views.

6 CommentsLeave a comment

  • I am an 82 year old woman who has been having a terrible time sleeping for many years. When I am asleep, I am not fully asleep, nor am I fully awake. I while in this “dream state” hallucinate and am a part of groups of people in my bedroom, or living room or wherever I happen to fall asleep. I talk out loud to those around me, but never receive an answer back. I am aware of the furniture around me as mine and always wonder how I am going to get it home. Does any of this ring a bell as a symptom of KLS? No one has been able to explain why this happens EVERY night.

    • Hi Carol
      Thanks for your comment. I don’t think what you describe sounds like KLS. But I do think it’s something to speak to your primary care doctor about to get their advice. It’s common for people to need less sleep with age, but it sounds like you’re having symptoms beyond simple sleep problems. I think getting a professional opinion would be beneficial for you.

  • Woah. I’m so awfully sorry that I haven’t been back since, but I think one can imagine the reasons for that? Of course I like to tell a bit more about my personal case :-) First I just studied a lot – really really a lot – then there were a few days of sleepless fatigue and… bam, there I slept. For me personally this is the typical way to slip into an episode: When I immerse myself into something that demands my fullest attention for an extended lapse of time, I can be quite sure that I’ll have to spend some days sleeping afterwards. This time that particular episode took me 8 days without doing anything than sleeping, eating, digesting and sleeping again plus 2-3 days of recovering and returning to a normal sleep pattern in which I usually sleep around 7-9 hours a night and aren’t sleepy or even narcoleptic in any way during daytime. By the way, “daytime” might be to defined – in addition to my special phenomenon I’m also an extremely late chronotype, my favoured time range to be awake is around 1200-0400. Living against this doesn’t trigger an episode though, so this isn’t a big problem to me.

    My episodes, usually taking 3-5 days except for when they were triggered by exhaustion which makes them taking up to 7-10 days, occur slightly less than once in a month up to once every second month on the other hand are. I simply suffer from the way people look at sleep in general and excessive sleeping in special which leads them to the conclusion that I have to be a lazy, lethargic person who doesn’t want to do anything… I’m not and I want to do so much and I do show that between my periods, but I’ll always be Miss Sleep-a-lot to them. So… I’d not even say that I do suffer from my episodes of excessive sleepyness very much but the way people look at me does. And so of course does my social life because nobody really wants to plan with the one who doesn’t come late just five minutes because she overslept but five days… but when I’m awake I just enjoy the spontaneousness I can’t enjoy while sleeping, so I got that going for me which I think is nice ;-) Okay. I could mourn over all the chances and possibilities I never got to grab because I was asleep. But what about all the chances and possibilitites life can provide which I never even got near to because of other reasons? Nope, that’s depressing, I won’t do that.

    Aside from the impacts on my social life there are some physical ones. For example my digestion… isn’t the best after hardly doing anything for a week, it gets… somewhat moody. At least I figured out that a high-carb-low-everything-else diet during an episode is a good way to avoid obstipation while a high-fat nutrition leads to instant diarrhea afterwards. By the way I never have experienced an episode during my menses – and I hope it will stay that way because that would be a bloody mess… okay, sorry for that horrible pun. (I so do hope that someone else who can need this information will read it and I’m not talking about that nasty stuff just for the heck of it :D ) And of course I don’t have any physical stamina the days after an episode and it isn’t possible for me to do sports regularly, if only because physical exhaustion may trigger an episode as well as the mental one or just because I’d be out of training again after the next episode.

    So you indeed could say that nearly every aspect of my life is affected by my sleep condition. But I think there is one thing extremely important to know and reflect and live by: Not only I can do everything everyone else can do, not only I can be proud of what I achive in life… I can do it with extra passion because I know what it is like if you can’t do it and I can be somewhat extra proud of my achievements because I know that everyone else who achieved the same had way more (awake) time to do so. I also don’t think of the time I spend asleep as wasted. I prefer to think of it as used well – I’m capable of lucid dreaming, so to me my episodes are just some extended time of brainstorming and planning what to do after waking up. So I do feel somewhat special, but kinda impaired or even disabled? No way! :-) Just a little girl with big dreams spending a lot of time dreaming them <3

    Dear Ethan, dear other readers, I hope I could give you some deeper insights into what living with KLS means to me personally. Of course I don't and can't speak for people with KLS in general as the particular forms of its manifestation might be too different from each other to let the individual impacts and consequences be comparable in any way. But that's what it's like to me. Feel free to ask me whatever you like to know, I'll answer – there are no stupid questions, never ever! :-)


    • Hi Marie
      Thanks so much for sharing your story, experience and thoughts. It’s very interesting, and hopefully will help other readers who either have the same condition, or are interested for whatever reason. I think it’s great that you manage to see it in a positive way – something I try to encourage readers to do for a variety of different sleep problems on this site.
      I wish you all the best, and that you continue making the most of life, and your dreams.

  • Dear Ethan, thank you a lot for this really informative text which I especially liked because it pleasantly differs from all those sensation seeking yellow press stuff one gets to read about the topic. Since I’ve never been officially diagnosed with KLS and don’t think it’s useful in any way to spend my awake lifetime with running from doctor to doctor just to hear that they can’t do anything for me, I’ll just be that strange girl who often sleeps a lot for now. I match all KLS symptoms and other causes are definitely out of discussion though. Just call me sleeping beauty, it at least gives my problems a cute romantic touch – as I was born in the same town as the Brothers Grimm, a fairytale-ish name for it might be somehow okay :D If you’d like to have some chat about living with KLS, feel free to contact me via e-mail. — Marie, 26, Germany

    • Hi Marie
      Thanks for your comment and compliment – I’m glad you liked the article. It would be great to hear more from you, and how you’re affected by this sleep condition. If you have a few minutes to pop back and talk a bit more about it.

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