What Are the Differences Between Narcolepsy and Sleep Apnea?

Sleep apnea is classified into three categories depending on the underlying cause:

• Obstructive sleep apnea. Obstructive sleep apnea is the most common type, affecting as many as 14 percent of men and 5 percent of women. It occurs when there’s a physical obstruction in your mouth or throat when you’re sleeping.
• Central sleep apnea. Central sleep apnea occurs when something interferes with the signal from your brain telling your body to take in air.
• Complex sleep apnea. Complex sleep apnea is a combination of obstructive and central sleep apnea.

Sleep apnea and narcolepsy can both cause daytime sleepiness, but other symptoms are very different.

Sleep apnea

Sleep apnea causes pauses in your breathing while you sleep. These pauses can last from seconds to minutes. Other signs and symptoms of sleep apnea are:

• excessive daytime sleepiness and drowsiness
• frequent loud snoring
• gasping for breath while asleep
• waking repeatedly
• dry mouth and headache after waking
• decreased sexual function and low libido
• frequent urination at night

Narcolepsy

Signs and symptoms of narcolepsy are:

• Excessive daytime sleepiness. People with narcolepsy experience excessive daytime sleepiness that can come on suddenly. They experience “sleep attacks,” in which they fall asleep without warning for seconds to minutes.
• Cataplexy. About 10 percent of the time, the first noticeable symptom is a sudden loss of muscle tone called cataplexy. These attacks can be minor, only causing drooping of your eyelids, or can affect your whole body and lead to collapse.
• Sleep paralysis. It’s common for people with narcolepsy to experience sleep paralysis. Sleep paralysis is a temporary inability to move while at the edge of sleep.
• Hallucinations. Some people experience vivid hallucinations, usually visual, as they’re falling asleep and during naps.
• Broken sleep. Many people with narcolepsy have difficulty staying asleep at night, despite daytime sleepiness.
• Automatic behavior while sleeping. People with narcolepsy may fall asleep during an activity such as talking or eating and continue for seconds or minutes with no awareness of what they’re doing.

Both sleep apnea and narcolepsy have multiple potential causes.

Sleep apnea causes

Blockages in your throat or neurological problems can cause sleep apnea. Contributing factors include:

• obesity
• large tonsils
• endocrine conditions such as:
  • hypothyroidism
  • acromegaly
  • polycystic ovary syndrome (PCOS)
• chronic lung diseases such as asthma or chronic obstructive pulmonary disease (COPD)
• heart failure or kidney failure
• some genetic conditions such as Down syndrome or a cleft palate
• neuromuscular conditions such as:
  • stroke
  • myotonic dystrophy
  • dermatomyositis
• Co-occurring conditions:
  • chronic lung diseases such as asthma or COPD
  • pregnancy

Narcolepsy causes

Narcolepsy is divided into type 1 and type 2. People with type 1 experience cataplexy, while people with type 2 don’t.

Almost everyone with type 1 narcolepsy has low levels of the protein hypocretin in the nervous system. This protein helps regulate sleep cycles and promote wakefulness. In some people, as many as 80 to 90 percent of the neurons that produce this protein are lost. A number of factors may contribute to abnormal levels of this protein, including:

• autoimmune conditions
• family history and genetic factors
• brain injuries

The cause of type 2 narcolepsy is still largely unknown.

Researchers are still investigating the link between narcolepsy and sleep apnea. However, it appears that people with narcolepsy may be more likely to have obstructive sleep apnea than people without narcolepsy.

Studies have found an association between narcolepsy and an increased body mass index (BMI). Likewise, research has found a positive correlation between obesity and obstructive sleep apnea. A BMI of 30 or higher is considered to indicate obesity, whereas a BMI under 25 is considered to indicate a moderate weight.

Studies published between 2000 and 2013 found that the prevalence of obstructive sleep apnea in people with narcolepsy ranges from 2 to 68 percent. The wide discrepancy is largely due to small sample sizes and varying definitions of obstructive sleep apnea.

In a 2019 study, researchers found that in a group of 141 people with narcolepsy:

• 26 people had type 1
• 65 percent of people with type 1 had obstructive sleep apnea (17 out of 26)
• 115 people had type 2
• 34 percent of people with type 2 had obstructive sleep apnea (39 out of 115)

In a 2018 study, researchers found that obstructive sleep apnea was the most common medical condition observed in 68 people with narcolepsy in Olmsted County, Minnesota.

People with sleep apnea haven’t been found to have higher rates of narcolepsy.

It’s possible to have narcolepsy and sleep apnea at the same time. Having both conditions together may make diagnosis more difficult.

Many other conditions can cause tiredness throughout the day. Some of these causes include:

• sleep deprivation
• medications such as:
  • sedatives
  • beta-blockers
  • antihistamines
  • anticonvulsants
  • antidepressants
  • opioids
• hypothyroidism
• insomnia
• frequent nighttime urination
• depression
• anxiety
• malnutrition
• brain injuries
• other sleep disorders such as restless legs syndrome
• neurological conditions such as:
  • Parkinson’s disease and parkinsonism
  • stroke
  • myotonic dystrophy
  • multiple sclerosis
  • brain tumors

Read on to learn about treatment options for sleep apnea and narcolepsy.

Sleep apnea

Sleep apnea treatment focuses on improving airflow while you’re sleeping and managing underlying conditions. It may include:

• weight loss
• continuous positive airway pressure (CPAP) therapy
• bilevel positive airway pressure (BiPAP) therapy
• sleeping on your side
• dental appliances
• surgery
  • to reduce upper airway obstruction
  • to implant pacemaker-like device to stimulate specific nerves going to the tongue
• managing underlying medical conditions

Learn about home remedies for sleep apnea here.

Narcolepsy

Narcolepsy is treated with lifestyle changes and medications.

Lifestyle habits include:

• taking short naps
• keeping a regular sleep schedule
• avoiding alcohol or caffeine especially before bed
• avoiding smoking
• daily exercise
• avoiding large meals before bed
• doing relaxing activities before bed

Medications include:

• modafinil
• amphetamine-like stimulants
• pitolisant (Wakix)
• solriamfetol (Sunosi)
• antidepressants
• sodium oxybate

Diagnosis of narcolepsy or sleep apnea begins with seeing your primary healthcare professional. They’ll give you a physical examination and review your medical history. If they suspect a sleep disorder, they may refer you to a specialist for further testing.

The gold standard for diagnosing obstructive sleep apnea is polysomnography. During the test, you’ll sleep at the sleep center or hospital, where the following will be measured:

• changes in blood oxygen levels, as measured by pulse oximetry
• the airflow in front of the nose and mouth
• the effort to breathe
• brain waves, as measured by an electroencephalogram (EEG)
• eye movement, as measured by an electrooculogram (EOM)
• the heart rate and rhythm, as measured by an electrocardiogram (ECG)
• muscle activity, as measured by an electromyograph (EMG)

Polysomnography is also used to diagnose narcolepsy. Another test used to diagnose narcolepsy is a multiple sleep latency test, which measures how long it takes for you to fall asleep. In some cases, a doctor may withdraw a sample of hypocretin from your cerebrospinal fluid by using a spinal tap.

Learn more about tests used to diagnose narcolepsy.

Learn more about tests used to diagnose sleep apnea.

It’s important to visit a healthcare professional if you suspect you have a sleep disorder for proper diagnosis and treatment.

Narcolepsy isn’t considered deadly, but sleep attacks can potentially lead to lethal accidents and injuries. Sleep apnea is linked to several life threatening conditions.

Narcolepsy and sleep apnea are two sleep disorders characterized by excessive daytime sleepiness. The symptoms between the two conditions vary widely. Narcolepsy is characterized by sudden sleep attacks that can occur at any time. Sleep apnea is characterized by disruptions in your breathing while sleeping.

It’s important to visit a doctor if you think you have either condition. A doctor can help you reduce your chances of complications.