Narcolepsy and epilepsy both affect the brain but in different ways. While they may share some symptoms, they’re different neurological conditions with distinct hallmark symptoms.

Narcolepsy and epilepsy sound similar, but they’re two very different conditions that involve irregular brain activity. They’re both neurological conditions, but narcolepsy is a disruption of the sleep-wake cycle, while epilepsy causes seizures.

The two conditions can coexist, but coexistence is rare. One type of narcolepsy can cause symptoms that resemble seizures, which can sometimes lead to a misdiagnosis of epilepsy.

This article takes a closer look at each disorder, treatment options, and what symptoms can be common to both.

Movies and television sometimes portray narcolepsy as a condition that causes people to suddenly fall asleep without warning. While that may occur, narcolepsy more often causes a symptom known as “extreme daytime sleepiness” (EDS): a feeling of being tired throughout the day regardless of how well you slept the night before.

Narcolepsy affects more than 125,000 people in the United States. It’s a neurological condition that interferes with your brain’s regular sleep-wake cycle.

Narcolepsy is similar to hypersomnia, another condition marked by EDS. Doctors often require a multiple sleep latency test to make a definitive diagnosis.

Doctors classify narcolepsy as type 1 or type 2. While EDS is the main symptom for both types, people with type 1 narcolepsy also experience “cataplexy,” a sudden loss of muscle tone or strength as well as muscle control. Cataplexy may lead to falls and other injuries.

Type 2 narcolepsy is milder and doesn’t include cataplexy. It’s about four times more common than type 1.

Epilepsy is a neurological disorder in which brain cells (neurons) send signals to your muscles and other parts of your body in a chaotic or atypically rapid fashion. These atypical signals can lead to seizures, which often feature uncontrolled muscle movement but can also affect your mood, behavior, and how you process different senses.

The Epilepsy Foundation suggests that about 1 in 26 people have epilepsy, and the disorder sometimes accompanies other conditions, such as:

EDS is the main symptom of narcolepsy, but people with epilepsy don’t necessarily have any sleeping issues.

Similarly, seizures are the hallmarks of epilepsy, but most people with narcolepsy don’t experience seizures or other noticeable muscle control difficulties.

People with type 1 narcolepsy may experience cataplexy. In some cases, this loss of muscle strength or control may appear as a seizure. People with epilepsy typically don’t remember having a seizure, while people with narcolepsy remain fully conscious during cataplexy episodes.

The causes and risk factors of narcolepsy aren’t entirely understood. One cause may likely be a combination of low levels of the brain chemical hypocretin (also called “orexin”), which plays a major role in regulating the sleep-wake cycle.

Other causes may include:

Although specialists don’t often know why a person develops epilepsy, a family history of epilepsy is an especially common risk factor. Other risk factors include:

Both narcolepsy and epilepsy are lifelong conditions without a cure, but medications and lifestyle adjustments can help you manage symptoms.

Narcolepsy treatment usually involves one or more medications, including modafinil (Provigil), a nervous system stimulant that helps manage EDS. Other commonly prescribed medications for narcolepsy include:

  • amphetamine-like stimulants (if modafinil isn’t effective)
  • antidepressants
  • H3 receptor blockers
  • sodium oxybate (Xyrem)

Lifestyle adjustments to help manage narcolepsy symptoms include keeping a consistent sleep schedule and taking daytime naps. If possible, avoid napping in the late afternoon or evening because this can interfere with nighttime sleep.

You may also need to avoid caffeine and alcohol because they can also affect your sleep-wake cycle.

Epilepsy treatment usually involves the use of antiseizure medications. Although dozens of different types of powerful antiseizure medications exist, a doctor will likely prescribe you one medication at a time to avoid dangerous or problematic interactions. If the first medication you try isn’t effective, you may need to try additional medications to find what works for you.

A healthy lifestyle that includes a balanced diet, regular exercise, sufficient sleep, and stress management may also help reduce the frequency and intensity of future seizures.

Many people with epilepsy experience sleep difficulties. A 2015 study suggests that, while the co-occurrence of narcolepsy and epilepsy is rare, it can occur and can make an accurate diagnosis difficult, especially when diagnosing the conditions in children.

Researchers in the 2015 study state that there’s no reason to suggest that the two conditions share a similar pathway to development. In the rare cases in which people have both, the development of each condition is unrelated to the other.

Narcolepsy and epilepsy are two uncommon and serious chronic neurological conditions that require lifetime medical care. If you experience excessive daytime sleepiness, see a healthcare professional for an evaluation.

EDS can be a sign of narcolepsy, but also other conditions, such as obstructive sleep apnea.

Epilepsy diagnoses usually occur during childhood, though anyone at any age can experience their first seizure. If you or your child has a seizure or sudden muscle control difficulties, call 911 or your local emergency services if it lasts more than 5 minutes. If it’s a fleeting experience, speak with a healthcare professional as soon as possible for an evaluation.

The sooner you can start treating neurological conditions like narcolepsy or epilepsy, the more likely you’ll be to successfully manage the condition and avoid severe complications.