Excessive sleepiness that intrudes on daily functions may affect teens and young adults. It also commonly accompanies depression. Stimulants and adherence to good sleep routines can alleviate symptoms.


Hypersomnolence is characterized by recurrent episodes of excessive daytime sleepiness or prolonged nighttime sleep that is not restorative. This excessive sleepiness is present despite a main sleep period lasting at least seven hours. 

Persons with hypersomnolence are compelled to nap repeatedly during the day, often at inappropriate times such as during work, a meal, or a social gathering. The sleepiness usually comes on gradually and is not experienced as a sleep "attack." The frequent daytime naps taken by a person with hypersomnolence disorder usually provide no relief from symptoms. Individuals with this condition often have difficulty waking from sleep and exhibit confusion, an inability to move, or combativeness for several minutes or hours until they become fully alert. Additionally, they may have a long main sleep episode (more than nine hours per day) and feel unrefreshed upon awakening. These symptoms must be present at least three times per week to receive a diagnosis of hypersomnolence disorder. 

Hypersomnolence disorder is considered to be acute if symptoms last for less than one month. The condition is considered subacute if symptoms last for one to three months, and persistent if symptoms last for more than three months. 

Other symptoms may include anxiety, increased irritation, decreased energy, restlessness, slow thinking, slow speech, loss of appetite, hallucinations, and memory difficulty. Some patients lose the ability to function in family, social, occupational, or other settings.

Hypersomnolence has a typical onset age of 17 to 24 years and is equally common in males and females. Approximately one percent of the European and U.S. population experiences symptoms of hypersomnolence, particularly the prolonged impairment of alertness upon waking (i.e. sleep drunkenness).


Symptoms of hypersomnolence disorder include:

  • Excessive sleepiness, despite getting at least seven hours of sleep per night
  • Recurrent daytime naps or lapses into sleep during the same day
  • Non-restorative nighttime sleep that lasts for more than nine hours
  • Difficulty fully waking from a long sleep and feelings of confusion or disorientation may last minutes or hours
  • Increased sleep time (up to 14 to 18 hours per day)
  • Significant distress or impairment in functioning as a result of excessive sleep

Other symptoms may include anxiety, feeling irritated, low energy, restlessness, slow thinking or speech, loss of appetite, and memory difficulty.

Hypersomnolence can be associated with depressive disorders, bipolar disorders, substance-related disorders, Alzheimer's disease, Parkinson's disease, and multiple system atrophy. 

To be diagnosed with hypersomnolence, excessive sleepiness cannot be due to the physiological effects of a substance or a general medical condition.


Hypersomnolence may be caused by drug or alcohol abuse, other sleep disorders such as narcolepsy or sleep apnea, or dysfunction of the autonomic nervous system. In some cases it results from a physical problem, such as a tumor, head trauma, or injury to the central nervous system. Certain medications, or medicine withdrawal, may also cause hypersomnolence. Medical conditions including multiple sclerosis, depression, encephalitis, epilepsy, or obesity may contribute to the disorder. Some people appear to have a genetic predisposition to hypersomnolence; in others, there is no known cause. 


Stimulants, such as amphetamine, methylphenidate, or modafinil may be prescribed. Other drugs used to treat hypersomnia include clonidine, levodopa, bromocriptine, antidepressants, and monoamine oxidase inhibitors (MAOIs). Changes in diet and behavior—for example, avoiding night work and social activities that delay bedtime—may offer some relief.

If you have trouble falling asleep night after night, or if you always feel tired the next day, then you may have a sleep disorder and should see a physician. Your primary care physician may be able to help you, or may be able to refer you to a sleep specialist. Most sleep disorders can be treated effectively.

Sleep research is expanding and attracting more and more attention from scientists. Researchers now know that sleep greatly influences our waking hours, and they realize that we must understand sleep to fully understand the brain. Innovative techniques, such as brain imaging, can now help researchers understand how different brain regions function during sleep and how various activities and disorders affect sleep. Understanding the factors that affect sleep may lead to revolutionary new therapies for sleep disorders.


  • American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Revised.
  • American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition
  • Textbook of Clinical Neurology. 3rd ed.
  • University of Maryland Medical Pages

Last reviewed 03/06/2018