Scientists consider narcolepsy a relatively rare condition. It may affect fewer 0.16% of people worldwide, although doctors have historically underdiagnosed the condition. However, doctors may be starting to diagnose narcolepsy more frequently.

Scientists define narcolepsy as a disorder that affects rapid eye movement sleep.

As a result, people with narcolepsy experience excessive daytime sleepiness, sleep fragmentation, and uncontrollable sleep attacks.

This article looks at the prevalence of narcolepsy, risk factors, underdiagnosis, and more.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

A closed eye belonging to someone with epilepsy. -1Share on Pinterest
Ronny Dyscher/EyeEm/Getty Images

Scientists divide narcolepsy into types 1 and 2, with the latter being more common.

According to a 2022 article, around 65.4 in every 100,000 people have type 2 narcolepsy. Contrastingly, around 14 in every 100,000 individuals have type 1 narcolepsy.

The main difference between the two types is that type 1 narcolepsy comes with cataplexy. This refers to sudden muscular weakness in response to strong emotions.

As the National Institutes of Health (NIH) explain, narcolepsy may arise from autoimmune conditions, genetic abnormalities, and sometimes, brain injury.

These factors can affect many populations, meaning that anyone can develop narcolepsy, at least in theory.

However, according to a 2022 review, some people are more susceptible to narcolepsy than others. The risk factors for the condition include age, as it is most common in people in their late teens, and gender, as it may be more common in females than in males.

It is worth noting that there is disagreement about the risk factors for narcolepsy. For instance, the NIH states that males and females are equally likely to develop this condition.

However, other research has pointed to higher rates of narcolepsy in men. That said, the research continues into the prevalence of the condition.

Is narcolepsy hereditary?

According to the NIH, most people with narcolepsy do not have a family history of this condition.

Individuals with narcolepsy are not likely to pass this condition on to their biological children. As such, narcolepsy is not a hereditary condition.

Despite this, family clusters of the condition do exist. Up to 10% of individuals with narcolepsy and cataplexy know of a close relative who also has this condition.

Some research indicates that narcolepsy may be getting more common.

A 2020 study describes a potential increase in narcolepsy prevalence between 2013 and 2016.

Across this period, in the United States, the number of recorded narcolepsy cases may have risen by up to 14%.

However, increasing numbers of recorded cases might not mean that the condition is getting more common.

As the study authors emphasize, the increase may result from improving diagnostic practices. In other words, doctors recognize and diagnose more narcolepsy cases than before.

However, the study found significant geographical differences in rates of narcolepsy diagnosis. According to the study authors, this could result from geographical differences in diagnostic methods.

According to the above 2022 review, doctors might routinely underdiagnose narcolepsy.

This review states that doctors often make narcolepsy diagnoses only 5 to 10 years after the onset of symptoms. There may be several reasons for this.

Polysomnographs — where doctors use a device to monitor a person while they sleep — and other sleep tests provide the best diagnostic tests for narcolepsy.

However, research states that doctors do not recommend these tests enough. One study found that in Germany, around 21.1% of people received a polysomnograph within 24 months of their narcolepsy diagnosis.

The differences in narcolepsy criteria might be another factor. Healthcare professionals use differing definitions for the condition, resulting in different estimates of prevalence.

According to a 2022 study, experts who use stricter criteria tend to record fewer cases of narcolepsy.

This section answers some frequently asked questions about the prevalence of narcolepsy.

How prevalent is narcolepsy worldwide?

Researchers do not know exactly how many cases of narcolepsy there are worldwide.

According to the National Organization for Rare Disorders (NORD), some estimates place the prevalence of the condition at 0.03% to 0.16% of the worldwide population.

Other estimates state it occurs in 1 in 2,000 people in the general population.

However, medical professionals often misdiagnose or are not able to recognize narcolepsy. Because of this, it is difficult to estimate its true prevalence worldwide.

Is narcolepsy considered a rare disease?

Yes, NORD considers narcolepsy a rare disease.

How many narcolepsy cases are there in the US?

Although scientists are unsure about the exact numbers, some research suggests that 142,600 people had narcolepsy in the U.S. between 2013 and 2016.

Scientists understand narcolepsy to be a relatively rare sleep disorder.

Some estimate that narcolepsy cases range from 0.03% to 0.16% of the worldwide population, but this figure may not accurately reflect undiagnosed cases.

Type 1 narcolepsy comes with cataplexy and is less common than type 2 narcolepsy.

Some research suggests that type 2 narcolepsy may affect 65.4 in every 100,000 people. By contrast, type 1 narcolepsy could affect around 14 in every 100,000 individuals.

Doctors have historically underdiagnosed narcolepsy. This may have been due to conflicting diagnostic criteria.

Some might also have been reluctant to recommend the best possible diagnostic tests. However, recent increases in recorded cases suggest that accurate diagnoses are increasing.