The objective of this study was to clarify the clinical
features of sighted patients with non–24-hour sleep-wake syndrome.
Clinical analyses of consecutive patients suffering from non–24-
hour sleep-wake syndrome.
The sleep disorders clinic at Kohnodai Hospital, National Center
of Neurology and Psychiatry, Japan.
Fifty-seven patients who were diagnosed consecutively as having
non–24-hour sleep-wake syndrome between 1991 and 2001 were
included in the study.
Measurements and Results:
The clinical features and sleep characteristics
of the patients were analyzed. A semistructured psychiatric interview
that included the criteria for Axis I or II disorders of Diagnostic and Statistical
Manual of Mental Disorders, Third Edition-Revised was conducted,
and relationships between psychiatric problems and non–24-hour sleepwake
syndrome were analyzed. The patient cohort included 41 (72%) men
and 16 (28%) women. The onset of non–24-hour sleep-wake syndrome
had occurred during the teenage years in 63% of the cohort, and the mean
( ± SD) period of the sleep–wake cycle was 24.9 ± 0.4 hours (range
24.4-26.5 hours). The mean sleep length of the patients was 9.3 ± 1.3
hours, and 44% of them had a sleep length of between 9 and 10 hours.
Psychiatric disorders had preceded the onset of non–24-hour sleep-wake
syndrome in 16 patients (28%); of the remaining 41 patients, 14 (34%)
developed major depression after the onset of non–24-hour sleep-wake
These results represent the first detailed clinical review of
a relatively large number of sighted patients with non–24-hour sleep-wake