Reliability and validity of the Japanese version of the Chalder Fatigue Scale among youth in Japan.

In the present study, the reliability and construct validity of the Japanese version of the Chalder Fatigue Scale was evaluated as a measure of severity of fatigue among young students in Japan. A healthy group comprised 27 Grade 6 primary school students and 28 Grade 1 junior high school students. The severely fatigued group were hospital outpatients with childhood chronic fatigue syndrome (n = 21).

Daily expression of clock genes in whole blood cells in healthy subjects and a patient with circadian rhythm sleep disorder.

In recent years, circadian rhythm sleep disorders in humans have been increasing. Clinical features characteristic of this disorder are well known, but the specific causes remain unknown. However, various derangements of circadian expression of the clock gene are a probable cause of this disease.