[Epidemiology of sleep disorders].

The survey of insomnia, sleep breathing disorders and circadian rhythm sleep disorders in the world included Japan were reviewed in this article. We introduced the 1995 annual report of the national research project team supported by the grant of the Ministry of Health and Welfare that 18.7% of men and 20.3% of women in the outpatients of 11 general hospitals of Japan had severe sleep problems, and 11.7% of the patients had the persistent insomnia. Okada et al. estimated a prevalence of 3.28% of men for the obstructive sleep apnea syndrome in Japan. The survey by the telephone and self-reported questionnaire in the general population was reported that the prevalence of possible patients of circadian rhythm sleep disorders was estimated at 0.44% of Japanese.