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Subjective sleep quality has been identified as an important clinical construct in psychiatric disordered patients. The Pittsburgh Sleep Quality Index (PSQI), one of the most widely used standardized measures to assess subjective sleep quality, generates a global score and scores seven components. The present study psychometrically assessed clinical(More)
Recent progress in biological clock research has facilitated genetic analysis of circadian rhythm sleep disorders, such as delayed sleep phase syndrome (DSPS) and non-24-h sleep-wake syndrome (N-24). We analyzed the human period3 (hPer3) gene, one of the human homologs of the Drosophila clock-gene period (Per), as a possible candidate for rhythm disorder(More)
There are few epidemiological studies on sleep loss and daytime sleepiness in the general adult population of Japan. A total of 4000 adult people, aged 20 and over, were randomly drawn from five areas of Japan, and 3030 individuals were interviewed and completed a questionnaire including information about sleep duration and sleep problems. Overall, 29%(More)
STUDY OBJECTIVES There is a long-standing controversy surrounding the existence of dream experiences during non-rapid eye movement (NREM) sleep. Previous studies have not answered the question whether this "NREM dream" originates from the NREM sleep mechanism because the subject might simply be recalling experiences from the preceding rapid eye movement(More)
The aim of this study was to compare circadian and sleep characteristics between patients with delayed sleep phase syndrome (DSPS) and healthy controls. The authors studied 8 DSPS patients and 15 normal controls. Serum melatonin concentration was assessed every hour for 24 h under dim light conditions. The sleep phase and the melatonin rhythm in DSPS(More)
We tested whether the human Clock (hClock) gene, one of the essential components of the circadian oscillator, is implicated in the vulnerability to delayed sleep phase syndrome (DSPS) and non-24-hour sleep-wake syndrome (N-24). Screening in the entire coding region of the hClock gene with PCR amplification revealed three polymorphisms, of which two(More)
STUDY OBJECTIVES This study examined the prevalence and correlates of sleep problems in Chinese schoolchildren. DESIGN AND SETTING A cross-sectional questionnaire survey was undertaken in Shandong Province, People's Republic of China. PARTICIPANTS A total of 2004 elementary school children (998 boys and 1006 girls) participated in the survey. (More)
OBJECTIVES Depressive symptoms are observed in a relatively large series of patients with delayed sleep phase syndrome (DSPS). This study was undertaken to investigate the prevalence, characteristics, and factors associated with depressive symptoms among DSPS patients. METHODS This study targeted 90 consecutive patients (54 men, 27.1±9.2 years old)(More)
Nine healthy male volunteers (mean age of 24) participated in two experimental sessions of random crossover design: a bright light (5000 lux for 5 h from 00:00 to 05:00 h) session and a dim light (10 lux for 5 h from 00:00 to 05:00 h) session. Subsequently participants entered an ultra-short sleep-wake schedule for 26 h, in which a sleep-wake cycle(More)
Recent studies have shown that functional variations in clock genes, which generate circadian rhythms through interactive positive/negative feedback loops, contribute to the development of circadian rhythm sleep disorders in humans. Another potential candidate for rhythm disorder susceptibility is casein kinase I epsilon (CKIepsilon), which phosphorylates(More)