Why Is It So Hard to Diagnose Narcolepsy?

Narcolepsy is a chronic neurological disorder marked by excessive daytime sleepiness. Everyone with narcolepsy has excessive daytime sleepiness.1

About half of people with narcolepsy have cataplexy. Cataplexy is sudden muscle weakness prompted by a strong emotion, such as laughter, surprise, or anger. It can make you collapse, slump over, or slur words.2-3

Other core symptoms that occur frequently are:2

  • Vivid hallucinations when you are falling asleep or waking up
  • Sleep paralysis ̶ being unable to move as you are falling asleep or waking up
  • Disrupted nighttime sleep ̶ waking up several times for 10 to 20 minutes at a time

Diagnosis delays

In a 2017 study, 82 percent of people said diagnosis took more than a year. Only half the patients received a diagnosis within 5 years of symptoms’ start.1 Children with narcolepsy were more than twice as likely as adults to have diagnosis delayed.1

Narcolepsy is not common. It affects about 1 in 2,000 to 3,000 people. Your doctor may not completely understand narcolepsy because he or she does not see many people with it.3,4

Difficulty diagnosing in children

Symptoms of narcolepsy begin most often between 10 and 20 years old. In more than half of people, symptoms begin before 18.2,5 Children and teenagers can have unusual forms of cataplexy, such as abrupt twisting movements that may look like a different neurological disorder.1 They may not be able to describe their symptoms as well as adults. They depend on parents or teachers to notice their excessive sleepiness. Their sleepiness may cause other issues, such as hyperactivity, lack of attention in class, or rapid mood changes.

Parents, teachers, and doctors may blame rapid mood changes on teenage mood swings. They may focus on hyperactivity and lack of attention, not realizing they are results of sleepiness. If a student falls asleep in class, the adults may think the student just stays up too late.1

Symptoms are variable

Common symptoms vary in how often they occur and how severe they are.6 Other symptoms vary widely. In a study, 1 out of 4 people reported depression. They said their most trying symptoms were fatigue and difficulty thinking, remembering, or paying attention.1,6 Other symptoms included:1,6

Diagnostic testing issues

Doctors use several tests to confirm the diagnosis or to rule out other disorders. Results are not always clear-cut. A detailed overnight sleep study in a sleep lab sometimes gives normal results. The Multiple Sleep Latency Test (MSLT) suggests narcolepsy if you fall asleep in less than eight minutes at various times of the day and if you enter rapid eye movement sleep during two or more naps. But the MSLT can be affected by other factors, such as recent shift work.7,8

A test may show that you have the genetic marker linked to narcolepsy. But the gene only increases your risk of narcolepsy. It will not confirm a diagnosis.7

Talk to your doctor

Diagnosis is complex and calls for the insights of a sleep specialist. Ask your doctor for a referral or find a sleep center near you that is accredited by the American Academy of Sleep Medicine.

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