Hypersomnia can cause you to feel very sleepy during the day. You might even fall asleep at inopportune times.

With hypersomnia, you feel sleepy even when you have had enough sleep or long hours of sleep.

Hypersomnia is a chronic sleep disorder. This means that you may have recurring symptoms of varying intensity over a long period.

Treatments often focus on reducing your symptoms. They can include taking stimulants or making lifestyle changes, such as avoiding caffeine and declining later-in-the-day social or work engagements.

Hypersomnia is sometimes used interchangeably with excessive daytime sleepiness (EDS) and is defined as an inability to stay awake, or to stay alert, during typical daytime hours. You may feel an uncontrollable need to sleep, or you may lapse into sleep or drowsiness unexpectedly.

The International Classification of Sleep Disorders 3rd Edition (ICSD-3) defines hypersomnolence as excessive sleepiness when wakefulness is expected and hypersomnia as a disorder characterized by hypersomnolence.

Many people who live with excessive daytime sleepiness find that it interferes with their daily functioning. Drowsiness or falling asleep at inopportune times can lead to challenges in your social, work, or home life.

In some cases, you may experience what is known as a sleep attack. When this occurs, you fall asleep without warning during the day. It could occur while eating, talking, working, or driving.

In addition to excessive daytime sleepiness or sudden onset of sleep during waking hours, it is not uncommon for other symptoms to occur too. According to the National Institute of Neurological Disorders and Stroke, some commonly reported symptoms you may experience include:

  • increased levels of irritation
  • anxiety
  • depression
  • lack of appetite
  • decreased energy
  • trouble with memory
  • restlessness
  • impaired thinking
  • hallucinations

According to the Genetic and Rare Diseases Information Center, some additional symptoms can include:

  • sleeping 11 or more hours in a 24-hour period and not feeling refreshed
  • episodes of feeling faint
  • non-refreshing naps during the day
  • “sleep drunkenness,” which is a feeling of not wanting to get up and trouble waking up
  • sleep paralysis
  • difficulty regulating body temperature

There are several potential causes of hypersomnia. However, in some cases, you and your doctor may not be able to find the exact cause.

Here are some causes doctors and scientists know about:

  • presence of another sleep disorder, like narcolepsy or obstructive sleep apnea
  • drug or alcohol misuse
  • problems with the autonomic nervous system, which controls involuntary actions and reactions
  • other medical conditions, such as multiple sclerosis (MS), depression, encephalitis, or epilepsy
  • physical problems, such as an injury to the central nervous system, a tumor, or head trauma
  • certain medications, such as antidepressants, opioids, and anticonvulsants
  • substance use and withdrawal, such as with alcohol
  • genetic predisposition such as a family member having hypersomnia or another sleep disturbance

In some cases, a medical professional will diagnose idiopathic hypersomnia which is a sleep disorder that is characterized by chronic excessive daytime sleepiness, an irrepressible need to sleep or daytime lapses into sleep, and in some cases difficulty waking up from nocturnal sleep or daytime naps.

The underlying pathophysiology is not well understood, and diagnosis requires exclusion of other more common causes of excessive sleepiness.

Hypersomnia shares some similar characteristics to other sleeping disturbances or disorders. In some cases, you may be living with another sleep condition that causes you to develop hypersomnolence.

The following are similar conditions to hypersomnia:

Sleep-wake disorders

Sleep-wake disorders involve problems with the quality, timing, and amount of sleep, which result in daytime distress and impairment in functioning. They are chronic conditions that affect your ability to get an adequate night of sleep. This broad category has symptoms such as:

Obstructive sleep apnea

Obstructive sleep apnea (OSA) is a disorder that causes your breathing to stop or suspend while you sleep. It can cause a non-refreshing night’s sleep, which can affect your wakefulness during the day. In addition, it can cause symptoms such as:

  • dry mouth, sore throat, or headache when waking
  • loud snoring or sounding like breathing is strained
  • frequently waking
  • waking up gasping for air


Narcolepsy is a type of sleep disorder where the brain has an impaired ability to control the sleep-wake cycle. It shares similar symptoms to hypersomnia, including:

  • excessive daytime sleepiness
  • visual hallucinations
  • sleep paralysis

However, if you are living with narcolepsy, you may also experience frequent nighttime waking and cataplexy. Cataplexy is a loss of muscle control, often during types of heightened stress.

Diagnosing the cause of hypersomnia is the first priority and dictates treatment approach. Treatment strategies can be highly variable and might include behavioral counseling about insufficient sleep and poor sleep hygiene.

If you have OSA, treatment may include continuous positive airway pressure (CPAP) or an oral appliance. Depending on medications that you might take, a change in type or dose of a medication that causes hypersomnolence may be part of your treatment plan.

Treatment will always focus on addressing the underlying condition when hypersomnia is due to a medical or mental health condition, such as chronic pain or depression.

If you are living with hypersomnia, you may want to consider taking some of these steps to help manage your symptoms:

  • Follow your treatment plan that you developed with your doctor and let them know if symptoms persist.
  • Try to avoid caffeine, especially later in the day to help prevent nighttime insomnia.
  • Try to engage in social activities at times when it will not interfere with your regular bedtime.

It’s also important to remember that regardless of the underlying cause, hypersomnia raises important considerations related to safety when driving or engaging in other activities that can endanger you or others. So be sure to take necessary precautions to help ensure everyone’s safety.