Sean Jackson
Author: Sean Jackson Medical Reviewer: Dr. Leila Khurshid Last updated:

Hypersomnia refers to a condition that involves excessive daytime sleepiness. Hypersomnia might be neurologically-based or caused by medications, drinking too much alcohol, or taking illicit drugs, and usually treated with lifestyle changes or therapy.[1]

What is hypersomnia?

Hypersomnia refers to excessive daytime sleepiness. Even after a long night’s rest, a person with hypersomnia might wake up not feeling refreshed. Moreover, patients might be so tired that they fall asleep during the day, even when they’re engaged in an activity like working, eating lunch, or talking with friends or colleagues.

In less severe cases of hypersomnia, patients might sleep throughout the night yet still be so tired that they need to nap several times throughout the day. As a result, people with hypersomnia are often drowsy and feel as though their mind is foggy. Moreover, hypersomnia often causes problems with concentration, memory, and decision-making.

Types of hypersomnia

There are two groups of hypersomnia: primary and secondary. While they share some symptoms, these versions of hypersomnia have very different causes.

Primary hypersomnia

Primary hypersomnia occurs when there is no known medical cause for the condition. The International Classification of Sleep Disorders (ICSD) Third Edition notes that there are four types of primary hypersomnia:[2]

  • Narcolepsy Type 1
  • Narcolepsy Type 2
  • Idiopathic hypersomnia
  • Kleine-Levin Syndrome

Narcolepsy is a different disorder that warrants a separate, detailed discussion. For our purposes, we’ll focus on the two other types of primary hypersomnia:

Idiopathic hypersomnia (IH) involves excessive daytime sleepiness, not feeling refreshed from a long night’s sleep or a nap, and difficulty waking up. Furthermore, people with IH often experience mental fogginess, grogginess, and disorientation. 

It’s believed that IH is a neurological disorder. Typically, sleep disturbances must occur for three months or more to qualify as IH. It often presents in the teenage years, though in some cases, it appears in childhood or much later in life.[3]

Kleine-Levin Syndrome (KLS) is a very rare type of primary hypersomnia that involves extremely long periods of sleep.

People with KLS sleep for up to 20 hours per day.[4] These sleep episodes occur abruptly, last for several days or weeks, and might not reappear for months. During these episodes, the waking hours might be characterized by abnormal behaviors, like hypersexuality or excessive eating.

KLS mostly occurs in adolescent males and is a chronic condition, though some medications (e.g., stimulants) can help mitigate sleepiness.[4]

Secondary hypersomnia

Secondary hypersomnia results from other medical conditions, particularly those that disrupt sleep at night. Common medical conditions that cause secondary hypersomnia include:[2]

  • Chronic fatigue syndrome
  • Insufficient sleep syndrome
  • Sleep apnea
  • Parkinson’s disease

Furthermore, secondary hypersomnia might occur due to prescription or non-prescription drugs (e.g., opioids, antihistamines, antidepressants) or a psychiatric disorder. For example, people with depression might also have hypersomnia. It isn’t currently understood if hypersomnia causes depression or if depression causes hypersomnia.[2]

Though secondary hypersomnias have similar symptoms (e.g., excessive sleepiness, grogginess, confusion), they vary greatly in their duration. For example, someone with Parkinson’s disease might have chronic hypersomnia. On the other hand, if hypersomnia results from taking medication, the symptoms might stop upon cessation.

Symptoms of hypersomnia

Chief among hypersomnia symptoms is excessive daytime sleepiness. As discussed earlier, people with some types of hypersomnia might sleep up to 20 hours per day. This disorder involves symptoms beyond excessive sleepiness, though. For example, additional symptoms might include:[3]

  • Low energy – Even simple daily tasks like laundry or cleaning the kitchen can become difficult due to extreme tiredness.
  • Sleep drunkenness – Sleep drunkenness refers to the difficulty of awakening from sleep and, once awake, pronounced grogginess and disorientation.
  • Slow speech – Again, the level of sleepiness is so extreme that people with this disorder might speak haltingly.
  • Irritability, anxiety, and brain fog – During awake periods, people with hypersomnia might be irritable and short with others. Moreover, feelings of anxiousness contribute to one’s irritability. Brain fog sometimes occurs when a person cannot concentrate or focus on tasks. 

In addition to these generalized hypersomnia symptoms, patients might experience other symptoms related to their specific type of hypersomnia. For example, someone with Kleine-Levin Syndrome might display excessive eating or hypersexuality, as outlined earlier, while someone with idiopathic hypersomnia might not.[4]

Causes of hypersomnia

The causes of hypersomnia depend on the situation. For example, it’s often much easier to pinpoint a cause of secondary hypersomnia. For example, someone with Parkinson’s disease might have secondary hypersomnia as a result of their medical condition. Likewise, someone that drinks alcohol heavily might be excessively sleepy because of the effects of their alcohol intake.

The cause of primary hypersomnia is more difficult to explain. It might result from a physiological condition, like reduced levels of histamine in the brain. Moreover, low-grade infections or brain damage might also lead to hypersomnia.[5] 

Regarding Kleine-Levin Syndrome, one hypothesis is that this type of primary hypersomnia is caused by a malfunction in the brain, specifically in the hypothalamus or thalamus.[4] These areas of the brain control sleep and appetite, which might explain why excessive sleepiness and excessive eating co-occur in KLS.

However, these are simply theories regarding the cause of primary hypersomnia. Since there are no known medical causes for primary hypersomnia, it’s often difficult, if not impossible, to identify why it develops.

In addition to these potential causes, many risk factors make it more likely for hypersomnia to develop. As discussed earlier, alcohol, prescription medications, and non-prescription drugs can all cause hypersomnia. Medical conditions like sleep apnea, restless leg syndrome, and other sleep disorders can also cause excessive daytime sleepiness. Other risk factors include:[6]

  • Shift work – Working an irregular schedule can disrupt your sleeping patterns, making it difficult to sleep and more likely that you develop excessive daytime sleepiness.
  • Chronic pain – Patients with chronic pain find it difficult to sleep, which can bring about symptoms of hypersomnia.
  • Environmental factors – City noise, a snoring partner, or having a newborn baby can all negativelyimpact sleep patterns that might result in hypersomnia.

Diagnosing hypersomnia

A hypersomnia diagnosis requires a physical exam to determine if there are obvious causes (e.g., Parkinson’s or a sleep disorder). Doing so can help medical professionals determine if the condition qualifies as primary or secondary hypersomnia.

Also, medical professionals will ask patients for details about their lifestyles and habits. This line of questioning is needed to determine if environmental factors, medications, or the patient’s emotional state might have something to do with their excessive sleepiness.

Sleep-related tests might be needed to determine if a different condition exists. For example, a doctor might order a sleep study to identify sleep disorders that might cause the patient’s sleepiness. A sleep latency test, which measures how long it takes to fall asleep, might also be necessary.

Lastly, a doctor might order a psychological evaluation to rule out mental health causes for sleepiness, like depression.

According to the DSM-5, primary hypersomnia is part of hypersomnolence disorders. The diagnostic criteria are as follows:[7]

  • Excessive daytime sleepiness occurs despite gettingat least seven hours of sleep
  • There are additional periods of sleep during the day.
  • At least one sleep period is at least nine hours and is not refreshing.
  • Becoming fully awake is difficult when awakened abruptly.
  • Sleepiness leads to significant impairment of functioning, including in the cognitive, social, and occupational realms.
  • Excessive daytime sleepiness happens three or more times a week and lasts for three months or more.
  • Hypersomnolence isn’t better explained by another sleep-related disorder.
  • If a mental health or medical condition also occurs, it does not fully explain the presence of hypersomnolence.
  • The condition is not caused by substance abuse or medication.

Prevention of hypersomnia

In some cases, secondary hypersomnia might be prevented by changing one’s lifestyle. For example, if a prescription medication is the cause of excessive sleepiness, an adjustment in dosage or changing to a different medication might bring about improved results.

However, most cases of hypersomnia, particularly primary hypersomnias, cannot be prevented. But, with appropriate treatments (discussed below), many patients can effectively manage their symptoms.

Treatment for hypersomnia

The most common type of hypersomnia treatment is medication, including those commonly used to treat narcolepsy. There are three main types of FDA-approved pharmacologic treatments for this disorder:[8] 

  • Stimulants – Amphetamine-based drugs like Dexedrine, Adderall, and Ritalin are effective in helping patients stay awake by stimulating the central nervous system. However, these medications often have many side effects ranging from mood changes to heart problems to the potential for dependence.
  • Non-stimulants – Some non-stimulant medications (e.g., Provigil, Alertec, Nuvigil, Acronite) are useful in promoting wakefulness, though it isn’t completely clear how these drugs Research suggests they affect dopamine production in the brain.
  • Oxybates – Oxybates (e.g., Xyrem, Xywav) are central nervous system depressants. These medications are taken at bedtime to help promote deeper sleep. 

Other hypersomnia treatment options aren’t FDA-approved. For example, Wellbutrin, an antidepressant, helps promote wakefulness by preventing dopamine and norepinephrine from being absorbed in the brain.[8]

Another option is selegiline (e.g., Eldepryl, Emsam). This monoamine oxidase type B inhibitor slows the breakdown of dopamine, norepinephrine, and serotonin in the brain.[8] As a result, these neurotransmitters become more active, which might help improve wakefulness. 

In some cases, melatonin might enhance sleep and caffeine to promote wakefulness in people with hypersomnia. People with Kleine-Levin Syndrome benefit from carbamazepine or lithium – drugs typically prescribed for mood disorders – which might help reduce the frequency of hypersomnia episodes.[4] 

Aside from medications, physicians often outline lifestyle changes that can help manage hypersomnia symptoms. For example, patients might be asked to maintain a strict schedule of activity and rest that includes a proper diet, meditation or mindfulness training, and planned naps. Furthermore, psychotherapy, group therapy, and support groups for people with sleep disorders can be beneficial for diminishing anxiety and stress.

Self-care for hypersomnia

Though hypersomnia can’t be prevented or cured, there are many strategies to supplement medications and non-medical treatments for this condition. These include:[1][6] 

  • Sticking to a regular sleep schedule that involves going to bed and waking up at the same time each day.
  • Avoidalcohol, nicotine, and caffeine close to bedtime.
  • Eating a proper diet and getting appropriate exercise.
  • Meditating, which can help induce calm before bedtime and improve the quality of sleep.
  • Minimizing distractions in the bedroom. Sleeping with a white noise machine to drown out environmental noise, wearing an eye mask to block out any light, and avoiding watching TV or reading in bed can all help improve nighttime sleep.

It’s also worth discussing hypersomnia with loved ones. The more they understand what’s going on, the more capable they will be of offering assistance.

Frequently asked questions about hypersomnia

How does hypersomnia impact daily life?

Hypersomnia can significantly impact a person’s ability to function, including in social and occupational realms, because of their level of sleepiness. Likewise, people with hypersomnia might not be able to drive because of the likelihood of falling asleep behind the wheel. 

How common is hypersomnia?

It’s estimated that hypersomnia affects four to six percent of the general population. Men are more likely than women to have this disorder.[9] 

Hypersomnia vs, narcolepsy – What is the difference?

Hypersomnia and narcolepsy are closely related. However, a primary difference between the two is that narcolepsy involves the sudden onset of deep sleep, while hypersomnia is characterized by excessive daytime sleepiness.

  1. National Health Service. (2020, August 4). Excessive daytime sleepiness (hypersomnia). Retrieved November 29, 2022, from https://www.nhs.uk/conditions/excessive-daytime-sleepiness-hypersomnia/
  2. Hypersomnia Foundation. (2022, February 27). Classification of hypersomnias. Retrieved November 29, 2022, from https://www.hypersomniafoundation.org/classification/
  3. Hypersomnia Foundation. (2022, February 27). Idiopathic hypersomnia. Retrieved November 29, 2022, from https://www.hypersomniafoundation.org/ih/
  4. National Institute of Neurological Disorders and Stroke. (n.d.). Kleine-Levin Syndrome. National Institutes of Health. Retrieved November 29, 2022, from https://www.ninds.nih.gov/health-information/disorders/kleine-levin-syndrome
  5. Stanford Medicine. (n.d.). Idiopathic hypersomnia. Retrieved November 30, 2022, from https://stanfordhealthcare.org/medical-conditions/sleep/idiopathic-hypersomnia.html
  6. Victoria State Government. (2014, June 30). Sleep – hypersomnia. Retrieved November 30, 2022, from https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/sleep-hypersomnia
  7. National Library of Medicine. (2016, June). 35DSM-IV to DSM-5 Hypersomnolence Disorder Comparison. Retrieved December 1, 2022, from https://www.ncbi.nlm.nih.gov/books/NBK519704/table/ch3.t35/
  8. Hypersomnia Foundation. (2022, April 16). Treatment for idiopathic hypersomnia & narcolepsy. Retrieved December 2, 2022, from https://www.hypersomniafoundation.org/treatment/
  9. Dauvilliers, Y., & Buguet, A. (2005). Hypersomnia. Dialogues in Clinical Neuroscience, 7(4), 347–356. https://doi.org/10.31887/DCNS.2005.7.4/ydauvilliers
Medical Content

Our Medical Affairs Team is a dedicated group of medical professionals with diverse and extensive clinical experience who actively contribute to the development of our content, products, and services. They meticulously evaluate and review all medical content before publication to ensure it is medically accurate and aligned with current discussions and research developments in mental health. For more information, visit our Editorial Policy.

About MentalHealth.com

MentalHealth.com is a health technology company guiding people towards self-understanding and connection. The platform offers reliable resources, accessible services, and nurturing communities. Its mission involves educating, supporting, and empowering people in their pursuit of well-being.

Sean Jackson
Author Sean Jackson Writer

Sean Jackson is a medical writer with 25+ years of experience, holding a B.A. degree from the University of Nottingham.

Published: Dec 21st 2022, Last edited: Sep 22nd 2023

Dr. Leila Khurshid
Medical Reviewer Dr. Leila Khurshid PharmD, BCPS

Dr. Leila Khursid is a medical reviewer with a Doctor of Pharmacy degree and completed a PGY1 Pharmacy Residency from St. Mark's Hospital.

Content reviewed by a medical professional. Last reviewed: Dec 21st 2022
Medical Reviewer Medical Reviewer:
Dr. Leila Khurshid
Last reviewed: Dec 21st 2022 Dr. Leila Khurshid

PharmD, BCPS