Narcolepsy vs. Insomnia: What's the Difference?

Medically Reviewed by Sabrina Felson, MD on July 16, 2023
4 min read

You have trouble sleeping through the night and you often nod off during the day. You might wonder if you have a sleep disorder like insomnia or narcolepsy. The two conditions are easy to confuse. Narcolepsy and insomnia are both sleep disorders. Both disrupt sleep at night and cause sleepiness during the day. But they affect your sleep in different ways.

Insomnia makes it hard to fall asleep and stay asleep. Narcolepsy is a problem with your sleep cycles that causes sleep attacks during the day and periods of disrupted sleep at night.

Both narcolepsy and insomnia can make you feel sleepy during the day. But with narcolepsy, you might fall asleep while driving or doing another activity. Or your body could suddenly go limp when you laugh or cry.

If you don't sleep well and you feel tired during the day, talk to your doctor. You also might want to keep a sleep diary leading up to the appointment. Keeping a sleep diary can help your doctor figure out whether you have narcolepsy or insomnia. For 1 to 2 weeks, write down when you go to sleep, wake up, and take naps. Share this diary with your doctor at your next visit.

Narcolepsy is a problem with your sleep-wake cycles. It's a type of hypersomnia, which means that it makes you very sleepy during the day.

Normally you go through four sleep stages. Rapid eye movement (REM) sleep is the deepest stage of sleep when you dream. It usually starts about 90 minutes after you fall asleep.

When you have narcolepsy, you enter the deep REM sleep stage quickly -- about 15 minutes after you fall asleep. You might also go into a dream-like state while you're awake.

People who have type 1 narcolepsy also have sudden muscle weakness with strong emotions, which is called cataplexy. For example, your knees might buckle when you laugh or cry. People with type 2 narcolepsy don't have cataplexy.

Narcolepsy also causes symptoms like these:

  • Waking up many times during the night
  • Falling asleep during the day, including during activities like talking, working, or driving
  • Not being able to move or speak as you fall asleep or wake up, called sleep paralysis
  • Seeing things that aren't real, called hallucinations

Insomnia is when you have trouble falling asleep, staying asleep, or sleeping soundly. The lack of sleep can make you feel tired or cranky the next day.

Insomnia can be short-term (acute) or long-term (chronic).

Acute insomnia lasts for a few days or weeks. Stress or changes to your schedule can cause this type of insomnia.

Chronic insomnia happens 3 or more nights a week and lasts for more than 3 months. It's not caused by a medical problem or a medication you take.

These are some common symptoms of insomnia:

  • Lying awake for a long time, unable to fall asleep
  • Waking up during the night or very early in the morning
  • Feeling like you're not well-rested
  • Feeling sleepy and having trouble concentrating during the day

Both insomnia and narcolepsy can make you feel extremely sleepy. With either condition, you might fall asleep during the day, even while driving. The difference is that narcolepsy causes "sleep attacks," where the tiredness comes on suddenly and you may not realize that you're sleeping. On the other hand, with insomnia, you would feel sleepy or fall asleep during the day because you haven’t been getting enough sleep at night.

The causes of each sleep disorder are different. Stress, major life changes, travel, or taking frequent naps can cause insomnia.

Other possible causes include:

Many people with narcolepsy have low levels of the chemical hypocretin. A lack of this chemical makes it harder for the brain to control sleep cycles. Experts believe that a problem with the immune system causes the drop in hypocretin.

Very rarely, genes may play a part. Less than 10% of people with narcolepsy have other family members with the condition.

Narcolepsy and insomnia have in common a chemical messenger called orexin. Nerve cells release orexin to help them talk to one another. Experts believe this chemical plays an important role in helping you stay awake and alert during the day.

People with type 1 narcolepsy have very few of the nerve cells that produce orexin. The lack of this chemical leads to symptoms like daytime sleepiness and cataplexy.

People with insomnia have too much orexin, which keeps them awake. Daridorexant (Quviviq and suvorexant (Belsomra) are insomnia treatments that works by blocking orexin. Researchers are studying narcolepsy treatments that boost orexin levels.

Insomnia can also be a symptom of narcolepsy. Even though you feel sleepy during the day, you can have trouble falling or staying asleep at night.