Sleep Disorders Documented by Night Polysomnography in Patients with Chronic Insomnia Disorder

Background: To investigate the sleep disorders related to chronic insomnia and compare the characteristics of each group.Methods: We registered 191 patients (female 56.0%, age 61.7 years) who have complained about symptoms of insomnia for more than three months and assessed sleep disorders related chronic insomnia by analyzing their polysomnography (PSG) parameters, demographics, and questionnaires (Insomnia Severity Index, Beck Depression Inventory, Pittsburg Sleep Quality Index, and Epworth Sleepiness Scale, and World Health Organization Quality of Life Assessment Instrument abbreviated version).Results: Patients were categorized into groups of primary insomnia (PI, 51.8%, n=99), comorbid insomnia with obstructive sleep apnea (CIO, 38.7%, n=74), and comorbid insomnia with periodic limb movement disorder (CIP, 9.4%, n=18).CIO was older and more obese than PI and CIP.The proportion of males was the highest in CIO.Arousal index of PSG was higher in CIO and CIP than in PI.Other parameters and the results of questionnaires were not different among groups.Conclusions: About a half of patients with chronic insomnia symptoms (48.2%) had considerable sleep disorders associated with insomnia.Our study suggests that the PSG as well as history taking and demographics are necessary to clarify the relevant conditions of chronic insomnia disorder for appropriate treatment.