Eveningness and insomnia: independent risk factors of nonremission in major depressive disorder.
BACKGROUND
It is unclear whether there is an association between chronotype and nonremission of depression, and whether the association is related to the confounding effect of insomnia.


METHODS
A cohort of patients with major depressive disorder were assessed for chronotype (by Morningness-Eveningness Questinnaire [MEQ]), depressive symptoms, insomnia severity and clinical outcomes in a naturalistic follow-up study.


RESULTS
Of the 253 recruited subjects (age 50.8 ± 10.2 y; female: 82.6%; response rate 90.0%), 19.4%, 56.1% and 24.5% patients were classified as eveningness, intermediate, and morningness, respectively. Evening-type subjects had higher insomnia severity, more severe depressive symptoms, and higher suicidality. Eveningness was associated with nonremission of depression with an odds ratio (OR) of 3.36 (95% confidence interval [CI] 1.35-8.34, P < 0.01), independent of insomnia severity. In addition, insomnia was an independent significant factor in contributing to nonremission of depression (OR = 1.12; 95% CI 1.05-1.19, P < 0.001).


CONCLUSIONS
The independent association of eveningness with nonremission of depression suggested a significant underpinning of circadian involvement in major depressive disorder. Our findings support the need for a comprehensive assessment of sleep and circadian disturbances as well as integration of sleep and chronotherapeutic intervention in the management of depression.
Department of Psychiatry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR.
Joey Wing Yan
JW
Chan
Department of Psychiatry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR.
Siu Ping
SP
Lam
Department of Psychiatry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR.
Shirley Xin
SX
Li
Department of Psychiatry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR.
Mandy Wai Man
MW
Yu
Department of Psychiatry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR.
Ngan Yin
NY
Chan
Department of Psychiatry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR.
Jihui
J
Zhang
Department of Psychiatry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR.
Yun-Kwok
YK
Wing
D002940:Circadian Rhythm / Q000502:physiology*; D003865:Major Depressive Disorder / Q000150:complications* / Q000503:physiopathology* / Q000523:psychology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012307:Risk Factors; D012890:Sleep / Q000502:physiology; D007319:Sleep Initiation and Maintenance Disorders / Q000150:complications* / Q000503:physiopathology* / Q000523:psychology; D013405:Suicide / Q000523:psychology
chronotype; depression; insomnia; nonremission