ABSTRACT
Insomnia has a range of clinical manifestations and involves a multitude of physical and psychological factors. In the International Classification of Sleep Disorders, second edition (ICSD-2) (1), a diagnosis of insomnia must confirm both the existence of nocturnal symptoms and a clinically significant impact during the patient’s waking state. Nocturnal symptoms include difficulty initiating or maintaining sleep, early awakening, and interrupted or nonrestorative sleep. Daytime symptoms include distress about poor nocturnal sleep and impairment in any role function or other aspects of overall well-being. Researchers have traditionally used quantitative criteria to diagnose insomnia, but these criteria have not been standardized. Quantitative criteria for the frequency and duration of total wake time and/or total sleep time have been proposed (2), but these criteria have not been uniformly employed.
