수면주기 지연 증후군 1례

A Case of Delayed Sleep Phase Syndrome

Whereas insomnia (disorders of initiating and maintaining sleep) and hypersomnia(disorders of excessive somnolence) have been studied for many centuries, physicians only recently become aware of that the sleep-wake rhythm itself can also be disturbed. Indeed, at this time we can only dimly perceive the importance of circadian rhythm for healthful sleeping. Not only do our internal circadian rhythm have to be properly entrained to the 24-hour cycling of this planet but it also seems crucial that an individual s usual bedtime hours be properly located within that individual s circadian rhythm. Delayed sleep phase syndrome is one of disorders of the sleep-wake schedule, which usually arises from mismatches between the patient’s circadian rhythm and society’s timetable. We experienced a case of salary man who developed delayed sleep phase syndrome for about one year. He had considerable difficulty in falling asleep at appropriated time in the night and increasing difficulty in awakening in the next morning. When not on a strict schedule(eg, weekends, holidays), he had a normal sleep pattern and after a sleep of normal length awaked spontaneously and felt refreshed. Polysomnographic recordings performed in our department for 3 consecutive nights demonstrated that he was noted only a dalayed pattern of sleep and awaking time. There was no evidence of significant organic diseases except hepatitis type B. Past history revealed no previous psychiatric disorders and no family history of psychiatric disorders.