Excessive daytime sleepiness is typically the earliest sign of narcolepsy, but it often isn’t detected until more severe symptoms appear.

Narcolepsy is a chronic brain condition characterized by irregular and disruptive sleep patterns. It impacts the central nervous system and causes issues with rapid onset rapid eye movement (REM) sleep in particular.

It’s a rare condition – an estimated 1 in 2,000 people have it, according to the National Organization for Rare Disorders.

Narcolepsy is most often associated with “sleep attacks,” which are uncontrollable urges to fall asleep.

But there are several other symptoms to know about, including:

  • daytime drowsiness
  • low quality, fragmented sleep
  • cataplexy (temporary, sudden loss of muscle control)

Although many people don’t notice they have narcolepsy until more severe issues like cataplexy develop, extreme daytime drowsiness is typically an earlier symptom

Here’s what to know about the condition and how it onsets.

The earliest sign of narcolepsy is typically excessive daytime sleepiness. Most of the time, this symptom onsets during adolescence, which is also a time when the tendency can be easily overlooked. Early symptoms of the condition typically occur from ages 7 to 25.

Since many adolescents experience hormonal shifts, sleepiness, and disordered sleep habits, the condition may go unnoticed until more serious symptoms occur. Narcolepsy is more likely to be detected in the teen years and beyond.

Narcolepsy type 1, which includes cataplexy, often goes noticed until episodes involving sudden loss of voluntary muscle control occur. These episodes can feel alarming and be potentially dangerous, so it often leads people to seek medical attention and an eventual diagnosis.

Narcolepsy type 2 doesn’t include symptoms of cataplexy. If narcolepsy type 2 is diagnosed, it might not be noticed until sleep attacks occur.

Narcolepsy is often misdiagnosed as another sleep condition, like insomnia, or a psychiatric disorder, like depression or schizophrenia. To increase the likelihood of a proper diagnosis and treatment, raising awareness about the varied signs of narcolepsy is key.

Experts don’t know the exact cause of narcolepsy, but they have some ideas. For instance, those with narcolepsy with cataplexy tend to have a decreased amount of a brain protein called hypocretin. Since hypocretin is key to regulating sleep cycles, this could play a role.

Low hypocretin levels are associated with a specific gene mutation and autoimmune issues.

Other possible factors that may contribute to the onset of narcolepsy include:

Although narcolepsy often goes undiagnosed, there are ways to diagnose and treat the condition successfully. When you visit a healthcare professional, they’ll ask you about your symptoms and your medical history to help aid in their assessment. They’ll also likely call for a few diagnostic tests, including:

Your doctor may also ask you for a detailed sleep diary, and you may have to complete a questionnaire called an Epworth sleepiness scale. They may also have you use an ActiGraph or another home diagnostic tool to track your sleep habits.

Your care team can also help identify other possible causes of your disordered sleep habits.

There’s not yet a cure for narcolepsy, but several approaches can help to manage symptoms.

These include:

  • Medication: Your healthcare professional may prescribe medications like antidepressants, stimulant medications, or sodium oxybate (Xyrem).
  • Healthy sleep hygiene: Going to bed at a regular time, limiting sleep interruptions, and creating a quiet, comfortable bedtime environment can help reduce symptoms. Short naps during the day can also help.
  • Lifestyle adjustments: Exercising regularly, avoiding heavy meals before bed, and avoiding caffeine, alcohol, and smoking may also help.

Read more about good sleep hygiene.

Though narcolepsy typically isn’t noticed and diagnosed until its later stages, one of the earliest symptoms of the condition is excessive daytime sleepiness.

If you experience daytime drowsiness, fragmented sleep, “sleep attacks,” or sudden loss of muscle tone, you may have narcolepsy. Although there’s no cure for narcolepsy, there are ways to manage it effectively. Visiting a healthcare professional can help you get the diagnosis and treatment you need.