Prevalence and clinical characteristics of insomnia and its subtypes in the Korean elderly.
BACKGROUND
Insomnia is known to be associated with psychiatric disorders, other sleep disorders and medical conditions, but the prevalence of insomnia diagnosis has never been estimated according to its subtypes. We studied the prevalence and clinical characteristics of insomnia diagnosis and its subtypes in the Korean elderly population.


METHODS
Among 1423 sampled elderly individuals aged 60 years or older, 881 subjects participated in this study. The Athens Insomnia Scale was applied to detect insomnia symptoms, and insomnia diagnosis was finally evaluated using the international classification of sleep disorders, 2nd edition. To define insomnia subtypes, the DSM-IV-based interview, detailed history on sleep disorders and semi-structured interview for medical conditions were performed. Subsyndromal depression was defined when depressive symptoms did not meet the criteria for depressive disorders.


RESULTS
The prevalence of insomnia disorder was 32.8% in all subjects, with the prevalence being significantly higher in women than in men (37.9% vs. 25.2%; p<0.001). The prevalence of insomnia subtypes was as follows; psychophysiological insomnia (PI), 20.5%; insomnia due to mental disorder 7.2%; insomnia due to general medical conditions 2.9%; insomnia in other sleep disorders 2.2%, and insomnia due to substance use 0.2%. Among subjects with PI, subsyndromal depression was diagnosed in 53.7%.


CONCLUSIONS
Nearly one third of Korean elderly individuals suffer from insomnia and insomnia patients showed diverse comorbid conditions, especially depressive symptoms. By establishing insomnia subtypes, we can plan to treat comorbid conditions as well as insomnia itself.
Department of Neuropsychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, South Korea; Department of Psychiatry, Seoul National University College of Medicine, Seoul, South Korea.
Ki Woong
KW
Kim
Department of Psychiatry, Veterans Health Service Medical Center, Seoul, South Korea; Department of Psychiatry, Center for Sleep Medicine, Seoul, South Korea.
Suk-Hoon
SH
Kang
Department of Neuropsychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, South Korea; Department of Psychiatry, Seoul National University College of Medicine, Seoul, South Korea. Electronic address: iyoon@snu.ac.kr.
In-Young
IY
Yoon
Department of Psychiatry, Korean Armed Forces Capital Hospital, Gyeonggi-do, South Korea.
Sang Don
SD
Lee
Department of Neuropsychiatry, Chungbuk National University Hospital, Cheongju, South Korea.
Gawon
G
Ju
Department of Neuropsychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, South Korea.
Ji Won
JW
Han
Department of Neuropsychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, South Korea.
Tae Hui
TH
Kim
Department of Neuropsychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, South Korea.
Chung Suk
CS
Lee
Department of Psychiatry, Kyung Hee University Hospital at Gangdong, Seoul,Seoul, South Korea.
Tae
T
Kim
D000368:Aged; D000369:Aged, 80 and over; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011569:Psychiatric Status Rating Scales; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D007319:Sleep Initiation and Maintenance Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology
Depression; Elderly; Insomnia; Insomnia subtype