• Journal of the Korean society of biological therapies in psychiatry
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• v.24 no.3
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• pp.194-201
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• 2018

Objectives : Some studies have reported that chronotypes, among several factors, could contribute to problematic drinking. However, there is little evidence confirming this relationship between chronotype and problematic drinking based on gender differences in mood disorder. This study is to investigate the difference of the relationship between chronotype and problematic drinking according to gender differences in mood disorder. Methods : Two hundred fifteen patients with mood disorder were recruited. Problematic drinking and chronotypes were assessed by the Alcohol Use Disorder Identification Test in Korea(AUDIT) and the Korean translation of composite scale of morningness(KtCS). We analyzed the correlation between KtCS and AUDIT using Pearson's correlation, and compared AUDIT scores according to chronotypes classified by KtCS between male and female patients using analysis of variance(ANOVA). Results : There was no significant difference in AUDIT scores between the male and female patients(t=0.91, p=0.183). In female patients, eveningness had significantly higher AUDIT scores than other chronotypes(F=0.199, p=0.033). Meanwhile, in male patients, there was no significant difference in AUDIT score among chronotypes(F=0.008, p=0.933). Conclusion : This study suggests that eveningness might be associated with problematic drinking in female patients who suffer from mood disorder. It also suggests that chronotherapeutical treatment might be able to help improve the course in female patients with mood disorder. In the future, a large-scale prospective study is needed to confirm these results.

• Korean Journal of Biological Psychiatry
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• v.21 no.3
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• pp.93-98
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• 2014

Objectives Circadian rhythms have been known to have associations with psychiatric disorders and personality traits. The present study investigated the relationships between circadian typology and temperaments/characters in a non-clinical Korean population. Methods Two hundred six healthy Korean college students (male 109, female 97) participated in this study. The subjects completed the Composite Scale of Morningness for circadian typology and 140-item Temperament and Character Inventory-Revised-Short version (TCI-RS). Results Multivariate analyses of covariance showed a significant association between chronotypes and temperamental dimensions of the TCI-RS. Morning types were significantly associated with lower harm avoidance and higher persistence and self-directedness dimensions, compared to evening types and intermediate types. No interaction effects between sex and chronotypes were shown for temperamental dimensions. Conclusions The present findings suggest that high persistence and self-directedness characters are related to morning types and high harm avoidance temperament is more related to evening types.

• Journal of Korean Biological Nursing Science
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• v.23 no.3
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• pp.227-236
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• 2021

Purpose: The purpose of this study was to investigate the sleep duration, social jetlag (SJL), and subjective sleep disturbance according to the individual chronotype in rotating shift nurses. Methods: A total of 344 rotating 3-shift nurses (mean age 28.67 years) were recruited at one university affiliated hospital. They completed the following questionnaires, which were used to assess their chronotype and sleep: the morningness-eveningness questionnaire (MEQ), self-reported sleep duration of work days (SDW_shift) and free days (SDF_shift) in each shift (day [D], evening [E], night [N]), and sleep disturbance (Insomnia severity index, ISI). SJL_shift was calculated as the difference in midsleep (MS=sleep onset+1/2 sleep duration) between work days (MSW) and free days (MSF). Results: Subjects were divided into 3 chronotype groups according to the MEQ; morning (MG, 4.4%) intermediate (IG, 57.8%), and evening groups (EG, 37.8%). SDW_D was shortest (4.68 hr) and SDF_E was longest (8.93 hr) in the EG. SJL_D was longest in the EG (3.77 hr), and SJL_N was longest in the MG (7.37 hr). The prevalence of sleep disturbance was 33.3% (MG), 29.6% (IG), and 40.0% (EG), respectively, without any statistical significance. Conclusion: In order to improve the sleep of shift workers, it is recommended that the evening chronotypes should reduce the day shifts and the morning chronotypes should reduce the night shifts. We also propose a study to determine whether these shift assignments can improve the sleep in shift nurses.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.47.1-47.14
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• 2023

Background: This study aimed to examine the impact of chronotype on depressive symptoms and explore the mediating effects of sleep quality, pre-sleep cognitive arousal, and social jetlag in a sample of wage earners. Methods: A total of 3,917 waged workers were surveyed online in July 2022. Logistic regression and mediation analysis were used to assess the relationship between chronotype (morningness, intermediate, and eveningness) and depressive symptoms (Patient Health Questionnaire ≥ 5), and the mediating effects of Insomnia Severity Index (ISI), Pittsburgh Sleep Quality Index (PSQI), and Pre-Sleep Arousal Scale (PSAS). All analyses were adjusted for age, education level, income level, marital status, coffee consumption, alcohol consumption, physical activity, occupation, employment status, and working hours to calculate odds ratios (ORs). Results: The chronotypes of all the participants were divided into morningness (4.7%), intermediate (93.5%), and eveningness (1.8%). Multiple logistic regression analysis showed an increased risk of depression in the eveningness chronotype (OR: 2.96; 95% confidence interval [CI]: 1.51, 5.86). Regarding the mediation analysis, ISI mediated 28.44% (95% CI: 16.39-40.5), PSQI for 31.25% (95% CI: 19.36, 43.15), and PSAS-Cognitive Score (PSAS-C) for 23.58% (95% CI: 10.66, 36.50) of the association between chronotype and depressive symptoms. However, social jetlag did not significantly mediate this relationship. (percentage mediated = 0.75%, 95% CI: -3.88, 5.39) Conclusions: Evening chronotypes exhibit an increased risk of depressive symptoms, which ISI, PSQI, and PSAS-C partially mediated. This suggests that interventions to improve sleep quality and maintain adequate sleep habits may effectively prevent and treat depression in employees with an eveningness chronotype.

• Sleep Medicine and Psychophysiology
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• v.26 no.1
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• pp.5-15
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• 2019

Chronotype (CT) is defined as an inter-individual difference in sleep-wake cycles and daily activities. Previous studies have suggested that this individual difference can influence our biological and psychological functioning. Literature regarding the psychometric properties and validity of CT measures are reviewed. We provide an overview of biological indicators (sleep-wake cycle, body temperature, cortisol, and melatonin) that are used for distinguishing two chronotypes: morningness (MT) and eveningness (ET). We also review the differences between CT in relation to personality traits and the occurrence of psychopathology. In addition, the methodological limitations of studies on CT are discussed. Finally, future research directions in terms of CT are proposed.

• Journal of Korean Critical Care Nursing
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• v.16 no.2
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• pp.15-27
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• 2023

Purpose : This study aimed to examine the relationship between sleep quality and its influencing factors in patients with coronary artery disease (CAD). Methods : This descriptive correlational study included 130 patients with CAD admitted to the cardiology department of a general hospital in B City between September 2019 and February 2020. Data were collected using structured questionnaires and research instruments to measure sleep quality, anxiety, depression, chronotype, and daytime sleepiness. Results : The mean scores for sleep quality, daytime sleepiness, anxiety, and depression were 7.59±3.45, 6.45±3.46, 6.58±3.88, and 7.74±4.05, respectively. In terms of chronotypes, 10.8%, 48.5%, and 40.7% of the participants had evening-, intermediate-, and morning-type patterns, respectively. Sleep quality was significantly correlated with anxiety (r=0.38, p<.001), depression (r=.37, p<.001), and daytime sleepiness (r=.26, p =.002). Factors associated with sleep quality in patients with CAD included anxiety (β=.29), heart failure (β=.22), daytime sleepiness(β=.21), and sleeping alone (β=.19). Collectively, these factors had an explanatory power of 23.1% for sleep quality variance. Conclusion: Patients with CAD often experience poor sleep quality owing to various factors such as anxiety, daytime sleepiness, heart failure, and sleeping alone. It is recommended that healthcare providers objectively evaluate sleep and identify factors that influence sleep quality. This will enable the development of effective methods for sleep management as part of nursing care.

• Journal of Sasang Constitutional Medicine
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• v.36 no.2
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• pp.27-38
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• 2024

Objectives The purpose of this study was to compare sleep quality and chronotype by Sasang constitution and examine the relationship with nutritional status. Methods This study used 672 follow-up data from the Korean Medicine Daejeon Citizen Cohort study (KDCC). Demographic, Sasang constitution, sleep quality, chronotype, and nutritional status evaluation were conducted based on questionnaires. Multiple linear regression analysis was used to confirm the relationship between sleep quality and chronotype according to Sasang constitution and nutritional status. Results The relationship between sleep quality and chronotype by Sasang constitution and nutritional status is that Taeeum nutritional index is related to sleep quality (adj. B = -0.46, 95% CI = -0.79 ~ -0.12) and chronotype (adj. B = 0.38, 95% CI = 0.24 ~ 0.52), and Soeum and Soyang showed an association between nutritional indices only in chronotype (adj. B = 0.43, 95% CI = 0.23 ~ 0.63 in SE, adj. B = 0.55, 95% CI = 0.38 to 0.73 in SY). Conclusions This study confirmed the relationship between sleep quality and chronotype and healthy eating habits. For a balanced nutritional status, overall sleep management is necessary. Based on the results of this study, we intend to use it as basic data on the impact of the relationship between nutritional status and chronotype by Sasang constitution on health.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.30.1-30.13
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• 2023

Background: Dysmenorrhea and menstrual cycle changes occur in women working shifts. Circadian rhythm disruption and sleep disturbances associated with shift work leads to health problems. We identified chronotypes and the occurrence of insomnia among newly employed university hospital nurses and investigated the association of these factors with menstrual problems. Methods: We conducted pre-placement health examinations for shift workers using self-reported questionnaires between 2018 and 2020. A total of 463 nurses were included in the study. Sociodemographic data, shift work experience, and information on insomnia were collected from health examination data. In addition, details regarding chronotype, dysmenorrhea, irregular and abnormal menstrual cycles, amenorrhea, and contraceptive use were obtained from the questionnaire. Multiple logistic regression analysis was performed to study the association between chronotype, insomnia, and menstrual problems after controlling for age, body mass index, contraceptive use, amenorrhea, and prior shift work. Results: The prevalence rates of dysmenorrhea, irregular menstrual cycles, and longer menstrual cycles were 23.8%, 14.9%, and 4.1%, respectively. The risk of dysmenorrhea increased in the evening-type (odds ratio [OR]: 3.209; 95% confidence interval [CI]: 1.685-6.113) and those with insomnia (OR: 1.871; 95% CI: 1.074-3.261). Additionally, the risk of an irregular menstrual cycle (OR: 2.698; 95% CI: 1.167-6.237) increased in the evening-type, and the risk of a longer menstrual cycle (OR: 4.008; 95% CI: 1.354-11.864) increased in individuals with insomnia. Conclusions: Our findings suggest that dysmenorrhea is promoted in the evening-type and insomnia individuals. There may be an increased risk of irregular menstrual cycles among evening-type nurses and an increased risk of longer menstrual cycles among those with insomnia. Therefore, factors such as evening-type and insomnia should be considered for the prevention of menstrual problems in women performing shift work.