Narcolepsy in Europe

First created | 05/04/2009

Last edited |

Adapted by Maurice M. Ohayon, MD, DSc, PhD
Reference to cite:

  1. Ohayon MM, Priest RG, Zulley J, Smirne S, Paiva Prevalence of narcolepsy symptomatology and diagnosis in the European general population. Neurology. 2002 Jun 25;58(12):1826-33.

Prior to our study, none of the previous studies in USA or in Europe have assessed the prevalence of the elements of the narcolepsy diagnosis in a large representative sample of the general population. Most prevalences were derived from clinical samples (Roth, 1980; Franceschi et al., 1982; Wilner et al., 1988; Wing et al., 1994) or from non-representative community samples (Solomon, 1945; Dement et al., 1972. 1973; Honda et al., 1983).

Narcolepsy is characterized by an imperative need to sleep suddenly and for brief periods, recurring at more or less close intervals. Narcolepsy was first labeled by Gelineau in 1880. Yoss and Daly, in 1957, completed the description of the disease and described the narcolepsy tetrad, which consists of:

  • sudden sleep periods,
  • cataplexy,
  • hypnagogic hallucinations, and
  • sleep paralysis

This description still prevails today in sleep disorders classifications (International Classification of Sleep Disorders and DSM-IV). Most prevalences are derived from:

  • clinical samples (Roth, 1980; Franceschi et al., 1982; Wilner et al., 1988; Wing et al., 1994)
  • non-representative community samples (Solomon, 1945; Dement et al., 1972. 1973; Honda et al., 1983)

According to these first studies, the prevalence varied from 20 to 67 per 100,000 inhabitants in Europe and North America (Franceschi et al., 1982; Dement et al., 1972. 1973; Hublin et al., 1994).

A study performed in Japan set this rate at 590 per 100,000 inhabitants (Tashiro et al., 1992). Another Japanese study set this rate at 160 per 100,000 inhabitants (Honda, 1979).

In Hong Kong, this prevalence was estimated to be between 1 and 40 narcoleptics per 100,000 inhabitants (Wing et al., 1994), and in Saudi Arabia 40 per 100,000 inhabitants (al Rajeh et al., 1993).

Another study performed with Jews in Israel, a population known for its low rate of human leukocyte antigen (HLA-DR2), a predisposing marker for narcolepsy, set the prevalence at 0.23 per 100,000 inhabitants (Wilner et al., 1988).

None of these previous studies assessed the prevalence of the diagnostic elements of the narcolepsy diagnosis in a large representative sample of the general population.

RESEARCH

To determine the prevalence of narcolepsy in the general population of five European countries. Target population: 205,890,882 inhabitants. Overall, 18,980 randomly selected subjects were interviewed (participation rate: 80.4%).

These subjects were representative of the general population of:

  • the United Kingdom
  • Germany
  • Italy
  • Portugal
  • Spain.

They were interviewed by telephone using the Sleep-EVAL expert system, which provided narcolepsy diagnosis according to the International Sleep Disorders classification (ICSD) and the Psychiatric Disorders Classification (DSM-IV).

RESULTS

Excessive daytime sleepiness was reported by 15% of the sample, with a higher prevalence in the United Kingdom and Germany.

Cataplexy (episodes of loss of muscle function related to a strong emotion), a cardinal symptom of narcolepsy, was found in 1.6% of the sample.

A narcolepsy diagnosis was found in 0.047% of the sample. The narcolepsy was severe for 0.026% of the sample and moderate in 0.021% of the sample. This was the first epidemiological study that estimated the prevalence of narcolepsy in the general population of five European countries. Narcolepsy affects 47 individuals per 100,000 inhabitants.

REFERENCE

Content of this page is extracted from:
Ohayon MM, Priest RG, Zulley J, Smirne S, Paiva T. Prevalence of narcolepsy symptomatology and diagnosis in the European general population. Neurology. 2002 Jun 25;58(12):1826-33.