Merck Manual

Please confirm that you are not located inside the Russian Federation

honeypot link

Insomnia and Excessive Daytime Sleepiness (EDS)


The Manual's Editorial Staff

Reviewed/Revised Apr 2022 | Modified Sep 2022
Get the full details

What are insomnia and excessive daytime sleepiness?

Insomnia is trouble falling asleep, trouble staying asleep, or getting poor-quality sleep. When your sleep is of poor quality you don't feel rested or refreshed in the morning.

Excessive daytime sleepiness (EDS) is having a lot of trouble staying awake during the day.

  • Insomnia usually causes EDS, but EDS has other causes besides insomnia

  • Insomnia and EDS may be caused by poor sleep habits but may also be due to a medical problem

  • If you have mild insomnia, a regular sleep schedule or other simple changes may fix the problem

  • If you have insomnia for a long time, you're at risk for other health problems

What causes insomnia or excessive daytime sleepiness?

Poor sleep habits are a common cause of insomnia, for example:

  • Napping a lot during the day

  • Drinking caffeine (for example, in soda, coffee, or tea) in the afternoon or evening

  • Watching an exciting TV show right before bedtime

  • Exercising within a few hours of bedtime

Other causes of insomnia include:

  • Stress, depression, or anxiety

  • Physical discomfort from health problems or injuries

  • Use of certain medicines or street drugs

Common causes of EDS include:

What are the symptoms of insomnia and EDS?

With insomnia:

  • You may have trouble falling asleep at bedtime

  • You may fall asleep normally but wake too soon and have trouble falling back asleep

With insomnia, you're likely to have EDS. You may take naps during the day to catch up. But napping creates a vicious circle. Napping makes it even harder to fall asleep at night. Then you want to nap even more the next day.

With EDS you're sleepy during the day and you:

  • May be irritable or have trouble concentrating

  • May fall asleep while at work or school

  • Have an increased risk of having a car crash

When should I see a doctor for a sleep problem?

See a doctor if your sleep problem interferes with your daily life, or if you have any of the following warning signs:

  • Falling asleep while driving or during other dangerous situations

  • Falling asleep often without warning

  • Waking up gasping or choking

  • A partner notices you stop breathing during sleep

  • Moving violently or hurting yourself or others during sleep

  • Sleepwalking

If you’re healthy and have had symptoms for 2 weeks or less, you can try to correct any poor sleep habits. If these changes don’t help after a week, you should see a doctor.

How can doctors tell if I have insomnia or EDS?

Doctors may have you fill out a questionnaire about your sleepiness. They may have you keep a sleep diary. In a sleep diary, you write down how you slept and how long. If doctors aren't sure what the problem is or how severe it is, they may send you to a sleep specialist. The specialist may do:

  • A sleep test

If the doctor thinks your symptoms may be caused by a medical problem, you may have blood tests or brain imaging tests such as an MRI.

What are sleep tests?

Because you can't tell the doctor what's happening when you're asleep, doctors have equipment that can monitor you while you sleep. Sleep tests may be done:

  • At home in your own bed

  • In a sleep lab in the hospital or doctor's office

For the home test, you go to bed wearing sensors under your nose, around your chest, and on your finger. A small device attached to the sensors records your breathing patterns and oxygen levels. It sends the information to the sleep doctor.

For the sleep lab test, you'll sleep overnight in the lab. This test uses more sensors. For example, sensors monitor your brain waves and eye muscle movements. Also, a sleep technician watches you sleep using a video camera that records all your movements and breathing. People worry that they won't be able to sleep in the lab wearing all the sensors. But most people sleep no worse than they do at home.

How do doctors treat insomnia and EDS?

Doctors will treat the cause of your problem if they can find the cause.

If your insomnia is mild, doctors may suggest:

  • Going to bed and getting up at the same time every day (even on weekends)

  • Having a bedtime routine

  • Keeping your bedroom dark and quiet

  • Spending time in bright light during the day

  • Getting regular exercise

  • Avoiding daytime naps (these can make it harder to fall asleep at night)

  • Limiting alcohol and caffeine and avoiding eating a lot before going to bed

If simple changes don't help, treatment may include:

  • Prescription or over the counter sleep aids (sleeping pills)

There are many different kinds of sleeping pills. Most are safe as long as your doctor helps pick out one that's right for you and watches out for side effects. Older people are more likely to have side effects, with both prescription and non-prescription sleep aids, particularly ones that contain antihistamines.

Drugs Mentioned In This Article

Generic Name Select Brand Names
Cafcit, NoDoz, Stay Awake, Vivarin
quiz link

Test your knowledge

Take a Quiz!