Hypersomnia: What It Is and How to Treat It

Excessive daytime sleepiness may seem like something outside of your control. But if you suffer from hypersomnia, there are things that you can do to feel better.

By Nicole Gleichmann

May 5th, 2022

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Expert Insights from Dr. Luis Javier Peña-Hernández, MD, FCCP, a lung health specialist at PCSI, the largest integrated pulmonary and chest specialty group in Palm Beach County.

Do you struggle with excessive sleepiness? Maybe you sleep fine throughout the night, but you still feel like you could fall asleep at any time during the day. Or you might feel incredibly lethargic when you wake in the morning, no matter how much you’ve slept.

Sleep disorders are common. So common, in fact, that many people feel as if their symptoms are a normal part of life. Fatigue, brain fog, sluggishness—we’ve all experienced these symptoms at one time or another. But if you can’t seem to get them to go away, you may have a condition called idiopathic hypersomnia (IH)(meaning that it arises from no known cause), also called hypersomnolence.

What is Hypersomnia?

“Hypersomnia is a neurological disorder characterized by excessive daytime sleepiness, brain fog, inability to sleep well, and excessive sleep period during the day,” explains Dr. Peña-Hernández.

IH, also known as excessive daytime sleepiness, is a neurological disorder. Early symptoms of hypersomnia include:

  • Excessively long sleep (over ten hours)
  • Difficulties getting out of bed (known as sleep inertia)
  • Brain fog or troubles thinking
  • Daytime sleepiness or fatigue
  • Feeling groggy in the morning, or throughout the day
  • Trouble focusing
  • An inability to sleep well
  • Difficulty waking up to alarms
  • Excessive sleep periods each day (usually taken to mean more than 10 hours)

Nearly everyone can relate to the above symptoms at one time or another. Because of this, people will often ignore these symptoms. Instead of seeing whether something is wrong, we’ll assume that it’s our own fault, or that everyone feels this way. This can lead to difficulties with diagnosis, leaving people with IH to suffer needlessly for long periods of time.

Eventually, chronic daytime sleepiness can grow from an inconvenience to a health hazard. As you can imagine, energy and sleep troubles can wreak havoc on your mental and physical health. If left untreated, IH can lead to:

  • Weight gain
  • Depression or other mood disorders
  • Anxiety
  • Poor performance at work or in school
  • Relationship difficulties
  • Other health conditions

If you seem to be fighting against daily fatigue, it’s important to learn what’s causing it. Only once you’ve identified the problem can you truly begin to find ways to solve it. Read on to learn more about hypersomnia, from what causes it to how it can be treated.

What Causes Hypersomnia?

“Hypersomnia can be caused by our genetics, environment, or lifestyle,” says Dr. Peña-Hernández.

Hypersomnia, also known as excessive daytime sleepiness, can be a condition in its own right, or it can be caused by another condition. These two varieties are known as primary or secondary hypersomnia.

Primary Hypersomnia

Primary hypersomnia is believed to be caused by dysfunction of certain brain systems. Our genetics, environment, and lifestyle can all contribute to troubles with the parts of our brains responsible for our sleep/wake cycle.

Research also suggests that some people over-produce a molecule that acts as a sedative. While the composition of this molecule is still unknown, we do know that it can enhance the sleep-promoting effects of the neurotransmitter GABA.

Types of primary hypersomnia include narcolepsy type 1, narcolepsy type 2, Kleine-Levin syndrome, and idiopathic hypersomnia.


Narcolepsy is a chronic neurological condition that affects less than 20% of the population and has no cure. Individuals suffering from this disorder may fall asleep unexpectedly, or struggle with extreme daytime drowsiness that interferes with normal functioning. This condition is often logistically challenging and can be socially isolating. It requires caution, or even restriction, when driving a vehicle or operating machinery.

Despite its relatively high profile, narcolepsy is actually quite rare, affecting about 1 in 2,000 people. However, it is estimated that fewer than half of narcolepsy sufferers are actually correctly diagnosed, and it may often be misinterpreted as a psychological disorder.

Narcolepsy presents equally in both men and women. There are three types of narcolepsy; type 1, type 2, and secondary narcolepsy.

Narcolepsy is a type of brain disorder that affects sleep, with numerous comorbidities. There is a link with autoimmune functioning and some of the research specifically classifies narcolepsy as an autoimmune disease. It can be triggered by emotion.

We know that narcolepsy is associated with rapid eye movement (REM) sleep. We know that people with narcolepsy fall into REM much faster than normal. It most often onsets in adolescence and is connected to hormones.

Anyone can have narcolepsy, but good sleep hygiene can help.

There are three types of narcolepsy, type 1, type 2, and secondary narcolepsy. Each is slightly different from the others and there are different causes and contributing factors. Each has in common the sudden falling asleep episodes that define narcolepsy.

Type 1 Narcolepsy

Type 1 narcolepsy always has cataplexy as one of its symptoms. Individuals with type 1 narcolepsy test low for a brain hormone called hypocretin, also called orexin. An episode of type 1 narcolepsy might onset just following some kind of heightened emotion and may result in slurred speech and loss of muscle function. You might laugh, and then your head might flop, and then you might fall asleep. These occurrences can happen as often as multiple times a day or infrequently like once or twice yearly.

Type 2 Narcolepsy

Type 2 narcolepsy has no loss of muscle control like with type 1, but it does have the same issues with falling asleep and daytime drowsiness. Strong emotions do not trigger or play a factor, although major psychological stress can be related. Type 2 is generally considered less severe, with milder symptoms. Individuals do not have the lower levels of hypocretin with type 2 narcolepsy.

Secondary Narcolepsy

Secondary narcolepsy is an ancillary rather than a primary diagnosis. It is designated when the narcolepsy is a symptom related to a more significant problem like a brain injury. Sometimes secondary narcolepsy happens in connection with other disorders like MS or an autoimmune disease.

Secondary Hypersomnia

Many times, excessive daytime sleepiness is caused by another condition that contributes to insufficient sleep quality or sleep deprivation. Additionally, these conditions can cause fatigue unrelated to poor sleep. Some conditions known to cause hypersomnia include:

  • Multiple sclerosis
  • Parkinson’s disease
  • Chronic fatigue syndrome
  • Obstructive sleep apnea
  • Kidney failure
  • Alcoholism
  • Chronic pain
  • Head injury
  • Hypothyroidism
  • Movement disorders
  • Obesity

Hypersomnia may be caused by other disorders such as depression, Celiac disease, mononucleosis or fibromyalgia, or it may arise as a by-product of other sleep disorders. It may also be in some cases an adverse reaction to certain medications, or result from drug or alcohol abuse. A genetic predisposition may also be a factor, as may excess weight. It is thought that the immediate mechanism for hypersomnia may be a particular somnogen (sleep-inducing substance) in the spinal fluid, although the substance’s exact identity and cause have still not been narrowed down.

Diagnosing Hypersomnia

“If you think you may be experiencing hypersomnia, you should speak with your doctor to discuss your symptoms,” says Dr. Peña-Hernández. “They will likely refer you to a sleep specialist or recommend that you undergo a sleep study.”

With 40% of us experiencing symptoms of hypersomnia at one time or another, it’s only natural to wonder if you have IH. Rather than comb the internet and try to self-diagnose (WebMD, anyone?), it’s best to contact your primary care physician to discuss your symptoms.

If your PCP determines that you do suffer from a sleep disorder, you’ll be referred to a sleep specialist for further evaluation. These visits can include questions to evaluate your symptoms, habits, other medical conditions, and drugs (like sleep medicines) that could cause IH.

For those who meet certain criteria, a sleep study might be scheduled. These include things like:

  • Six months or more of hypersomnia symptoms
  • A lack of underlying medical condition that might be causing IH
  • A Multiple Sleep Latency Test of fewer than ten minutes

In recurrent hypersomnia, the symptoms recur several times during the year, in between periods of relatively normal sleep-wake cycles, and may also be accompanied by other psychological disorders such as hypersexuality or compulsive eating.

Additionally, if an underlying condition is suspected to be the cause of your hypersomnia, further tests may be ordered to identify and help treat the condition.

Treating Hypersomnia

“Hypersomnia can be treated with prescription medications or lifestyle changes like exercising, reducing alcohol and caffeine consumption, and other sleep hygiene practices,” says Dr. Peña-Hernández.

There is no single universal treatment for people with idiopathic hypersomnia. Treatments for IH vary widely depending on the root cause. A combination of prescription drugs and lifestyle changes are often recommended.

Prescription Drugs Used for IH

Prescription drugs used to treat primary hypersomnia often address daytime sleepiness. Drugs for narcolepsy, a separate sleep disorder, are frequently prescribed to IH patients. According to the Hypersomnia Foundation, the narcolepsy medication modafinil has demonstrated efficacy at helping control IH symptoms in human clinical trials.

Unfortunately, modafinil, stimulants, and other narcolepsy drugs don’t work for everyone with hypersomnia. Additionally, they often come with side effects, and their efficacy can fade over time.

For secondary hypersomnia, drugs and other treatments are used that address the underlying cause. For example, those with daytime sleepiness caused by sleep apnea may be prescribed continuous positive airway pressure machines that can help you sleep through the night.

Lifestyle Changes for Excessive Daytime Sleepiness

Lifestyle changes are often recommended to help normalize the sleep/wake cycle. These can be aimed at improving sleep quality, reducing time to fall asleep, and enhance overall health. Some lifestyle changes that may help include:

  • Controlling alcohol and caffeine intake (particularly in the evenings)
  • Implementing a sleep schedule
  • Exercising
  • Eating a healthy diet high in vitamins and minerals
  • Quitting smoking
  • Not eating or drinking before bedtime
  • Practicing relaxation techniques
  • Limiting blue light exposure at night

Additionally, the National Sleep Foundation recommends for those with hypersomnia to discuss their condition with those close to them. By helping your coworkers, friends, and family understand what to expect, you can build a support system to help you through the tough times.

Because the causes for hypersomnia vary from one person to the next, the best form of treatment also differs. Working with sleep specialists can help you determine the best course of action for you.

A Look At Recurrent Hypersomnia: Kleine-Levin Syndrome

Kleine-Levin Syndrome (KLS) is a neurological and sleep disorder that’s most common amongst adolescent males (around 70% of those with this condition are male). It’s characterized by recurring periods of excessive sleepiness and cognitive troubles that come and go over the course of many years.

There are many other possible symptoms, although the exact symptoms vary from one patient to another. One of the most interesting aspects of this disease is that it nearly always tapers off with age. While most people will experience a full recovery in around 4-8 years, there are some people who fall outside of this range.

In a review that looked at 110 patients with primary KLS, the shortest disease frequency was 6 months, and the longest was 41 years. Rarely, people who think that their KLS has completely resolved can experience a sporadic episode later in life.

Thanks to the unpredictability of this condition, it’s particularly difficult for those affected to maintain a high quality of life. It nearly always interferes with work and school and can be a burden on family, friends, and other caretakers.

Symptoms of Kleine-Levin Syndrome

There is no one set of symptoms that applies to all affected individuals. The most common symptom is the need for excessive sleep, totaling up to 20 hours per day. A lack of sexual impulse control and compulsive eating are two of the other common symptoms.

Other symptoms include:

  • Behavioral disturbances: Irritability, childishness, apathy, and other behavioral abnormalities.
  • Hallucinations and confusion: Patients often experience periods of confusion or full-on hallucinations. They might describe episodes as hazy or confusing.
  • Cognitive abnormalities: Difficulties with speech, memory, learning, and focus can occur.
  • Mood troubles: Some patients show signs of depression during episodes and appear manically happy for a short period following recovery.
  • Compulsive behavior: Compulsive singing, writing, body rocking, pacing, and other behaviors have been noted.
  • Hypersensitivity: Patients may be overly sensitive to light and sound.

Symptoms come on unexpectedly and typically last anywhere from a few days to a few weeks. These periods are often referred to as “episodes.” In between episodes, patient’s will return to their normal selves, with sleep, behavior, and cognition normalizing. This healthy period can range from weeks to months.

While some people will remember what happens during their episodes, others will suffer from partial amnesia, not clearly remembering what they said or did.

KLS episodes tend to become less frequent, intense, and long as one nears the end of the disease. Eventually, the disorder will spontaneously disappear, allowing those affected to return to living a normal life.

Who is at Risk?

While most affected individuals display their first symptoms in their teen years, adolescents are not the only ones at risk. In a systematic review of published articles on KLS patients, researchers found that:

  • The median age of onset was 15 years old
  • There was a 2:1 ratio of men to women affected
  • The ages of those affected ranged from 4 to 82 years old
  • Israel had the highest prevalence, although it was found in many countries throughout the world
  • 6 patients experienced disease onset at 35 years or older

On average, women experience a longer duration of this disease when compared with men, despite other factors being similar. These include the age of onset and episode frequency, duration, and symptom severity.

Additionally, the studies and articles published suggest that KLS might be more prevalent in the Jewish population. It isn’t known whether this pattern is thanks to an increased risk in the Jewish community or to a reporting bias. For instance, it’s possible that more articles have been published in Israel due to a factor other than higher disease frequency, such as a local expert who is dedicated to doing KLS research.

There is even evidence of this condition having a genetic component, such as multiple families experiencing more than one person with KLS. More research is needed to determine if there is, indeed, a hereditary component.

What Causes Kleine-Levin Syndrome?

Researchers are still on the hunt for the cause of this bizarre disease. It’s believed that the symptoms may be due to something going awry in the regions of the brain responsible for sleep patterns and appetite, the hypothalamus and the thalamus.

There is evidence that KLS onset may be caused by an infection or another occurrence that happens directly prior to the initial episode. In the systematic review discussed earlier, researchers found that over 2/3 of patients experienced an infection or fever immediately prior to initial onset. This high incidence makes it likely that a pathogen is involved in KLS pathogenesis.

Unfortunately, the research thus far has not discovered a pathogen responsible for KLS. For those who did experience an illness or infection prior to the start of the disease, the pathogens responsible for the illnesses were not the same. This led researchers to conclude that KLS might be caused by an unknown disease agent, or that certain infections might uncover a previously existing disease.

Diagnosing KLS

There is no test for KLS. Most people with KLS leave the doctor with test results that would indicate a clean bill of health.

Researchers have searched for telltale signs of the disease. This includes testing for brain lesions, cerebrospinal fluid abnormalities, brain imaging, and more. Unfortunately, none of these tests have found a KLS marker.

If you believe that you or one of your family members has developed KLS, visit your primary care physician. They will likely refer you to a specialist to rule out other conditions. If your tests do not reveal any other condition and you exhibit the typical symptoms of KLS, you will likely be given a KLS diagnosis.

Final Thoughts

If you feel excessively sleepy no matter how long you sleep at night, you might be suffering from idiopathic hypersomnia. While obtaining a diagnosis for a sleep disorder might seem daunting, it’s the first step towards feeling like yourself again. Do yourself a favor and reach out to your primary care physician or a sleep specialist today.

Once you have a diagnosis, you can start an individualized treatment program to help regain your energy and quality of life. Remember, feeling fatigued and groggy throughout the day is not normal. You deserve to lead a life without excessive daytime sleepiness.

Expert Bio

Dr. Luis Javier Peña-Hernández, MD, FCCP, is a lung health specialist at PCSI, the largest integrated pulmonary and chest specialty group in Palm Beach County. His areas of expertise include asthma and immunotherapy, COPD, lung cancer, and invasive diagnostic techniques in pulmonary medicine including endo-bronchial ultrasound and diagnostic bronchoscopy. He is also one of the few experts in cardiopulmonary exercise testing and exercise physiology in Palm Beach County.