ABSTRACT
Until the beginning of the 1990s there were only about one dozen studies on the prevalence of narcolepsy, the earliest published in 1945 by Solomon (1). Despite great differences in definitions of the disorder, study populations, diagnostic procedure, and other methodological aspects, the results gave quite a remarkable 2500-fold difference in the prevalence, ranging from 0.23 to 590 narcoleptic subjects per 100,000 of population. Nevertheless, 95% confidence intervals could be calculated in eight studies and they overlapped or nearly overlapped in seven of them, indicating that the prevalence probably is in the range of 10-100 per 100,000.
