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Purpose: This study investigated the relationship between increased working hours and suicidal ideation among Korean full-time employees by gender.Methods: Participants were employees from 54 companies and local government organizations in Korea, aged 19 to 68, who completed a self-reported questionnaire on sociodemographic factors, daily perceived stress, resilience, depressive symptoms, and suicidal ideation. Of the initial 15,360 respondents, participants who worked less than 40 hours were excluded. The final sample size was 9,326 (5,652 men, 3,674 women). Sociodemographic factors and psychological characteristics of participants with suicidal ideation were analyzed using Student’s t-tests and chi-square tests for continuous and categorical variables, respectively. Hierarchical logistic regression analyses were performed using suicidality as the dependent variable respectively for all participants, for male, and female. Furthermore, we used these results to compare differences between men and women associated with regard to long working hours to better understand how long working hours correlate with suicidal ideation; further, we examined the impact of gender on this relationship.Results: In univariate analyses, suicidal ideation was associated with increased working hours. Hierarchical logistic regression analyses of sociodemographic and psychological factors found no association between long working hours and suicidal ideation for the participants overall. However, they showed significant differences between men and women, such that long working hours were associated with suicidal ideation in men but were non-significant for women.Conclusion: Suicidal ideation is associated with long working hours among Korean male full-time workers, while other factors are more likely to lead to suicidal ideation among female workers. Suicide prevention measures for employees should thus be developed based on gender.

This study aimed to investigate the association between gut microbiota and depressive symptoms in a large population cohort of Korean adults.Overall, 1238 participants were included in the study. Participants were categorized into depressed or non-depressed groups, based on the depressive symptoms reported on the Center for Epidemiologic Studies Rating Scale for Depression, with a cutoff score of 16, and their fecal microbiota was profiled using 16S ribosomal RNA gene sequencing. Several alpha and beta diversity measures were also estimated. The association between depressive symptoms and gut microbiota was analyzed using generalized linear models. The inferred function of the metagenomes was compared between the two groups.There were no consistent differences in alpha and beta diversity between the depressed and non-depressed groups. However, the continuous measure of depressive symptoms was inversely associated with one of four measures of alpha diversity (Shannon's diversity, p = .021). We also found a substantial difference between the depressed and non-depressed groups in the Bray-Curtis dissimilarity among the four beta diversity indices ( p = .004). Participants whose depressive symptoms exceeded a clinical cutoff score had a lower relative abundance of the genus Faecalibacterium when compared with controls (coefficient = -0.025, q = 0.047). However, the depressed group had a significantly higher abundance of the genus Oscillospira than did the non-depressed group (coefficient = 0.002, q = 0.023).Our findings contribute to the identification of potential relationships between the gut microbiota and depressive symptoms and provide useful insights for developing microbiota-based interventions for patients with depressive symptoms.

The aim of this study is to identify occupational stress associated with the development of new-onset anxiety symptoms and the dose-response relationship between sleep duration and the onset of anxiety symptoms. Data from 29,251 healthy employees who had undergone at least two comprehensive health examinations at Kangbuk Samsung Hospital Health Screening Center were analysed. Anxiety symptoms were assessed using the Beck Anxiety Inventory. Occupational stress and sleep duration were measured using a self-reported questionnaire about total sleep time and the Korean Occupational Stress Scale-Short Form (KOSS-SF), respectively. Flexible parametric proportional hazards model used to estimate the hazard ratios. Compared with the groups without case-level anxiety, discomfort in an organizational climate, high job demands, job insecurity, organizational injustice and lack of reward were associated with the onset of case-level anxiety. Compared with less than 6 hr of sleep per day, the beneficial level of sleep duration was 7 ≤ to

Objective The aim of study is to investigate the relationship between serum vitamin D, c-reactive protein (CRP) levels, and anxiety symptoms.Methods Serum vitamin D and CRP levels of 51,003 Korean adult participants were collected retrospectively. Anxiety symptoms were assessed using the Korean version of Beck Anxiety Inventory. Logistic regression was used to estimate the odds ratio (ORs) of anxiety symptoms by serum vitamin D and CRP levels. The regression was adjusted for covariates, and each model was adjusted mutually for vitamin D and CRP levels.Results Compared with sufficient vitamin D levels (≥20 ng/mL), insufficient (10–19.99 ng/mL) and deficient (

Maintaining adequate levels of sleep and physical activity (PA) as self-help for the prevention of new-onset anxiety symptoms is becoming more important.A cohort study was performed with 134,957 adults, free of anxiety symptoms at baseline who underwent at least two comprehensive health screening examinations between 2012 and 2017. At baseline, the amount of PA was measured using the International Physical Activity Questionnaire-Short Form and sleep duration per day was assessed using a self-report questionnaire. The study's end point was new-onset anxiety symptoms, defined as a Beck Anxiety Inventory score of ≥19.During 361,969 person-years of follow-up, 5086 participants developed case-level anxiety. Compared with a reference (0-600 METs-min/wk), a U-shaped relationship was observed between PA and case-level anxiety. The most beneficial levels of PA for reducing incident anxiety symptoms were higher in men than women (men: 1800-3000 METs-min/wk HR, 0.88 [95% CI, 0.78-0.81], 3000-6000 METs-min/wk HR, 0.81 [95% CI, 0.70-0.93]; women: 600-1,200 METs-min/wk HR, 0.86 [95% CI, 0.76-0.98]). In comparison with a reference (6 h), the relationship between sleep duration and case-level anxiety also had a U-shaped pattern. The optimal sleep duration for decreasing the onset of case-level anxiety was 7-8 h, regardless of sex (men: HR, 0.75 [95% CI, 0.63-0.90]; women; HR, 0.61 [95% CI, 0.54-0.70]).PA, sleep duration, and anxiety symptoms were measured using self-report questionnaires.The results of this study revealed the appropriate levels of PA and total sleep time for reducing incident anxiety symptoms.

Aims There has been increasing evidence of hormonal changes during reproductive events that lead to mood changes. However, studies on the severity of psychological problems according to the menopausal stage are limited. Thus, this study aimed to investigate the association between menopausal stages, depression and suicidality. Methods A total of 45 177 women who underwent regular health check-ups between 2015 and 2018 at Kangbuk Samsung Hospital were included. Participants were stratified into four groups (pre-menopause, early transition, late transition and post-menopause) based on the Stages of Reproductive Aging Workshop Criteria. The Center for Epidemiological Studies-Depression scale (CESD) was used to evaluate depressive symptoms, and the degree of depressive symptoms was classified as moderate (CESD score 16–24) or severe (CESD score ⩾ 25). To measure suicide risk, we administered questionnaires related to suicidal ideation. Results Overall, the prevalence of CESD scores of 16–24 and ⩾ 25 was 7.6 and 2.8%, respectively. Menopausal stages were positively associated with depressive symptoms in a dose-dependent manner. Multivariable-adjusted prevalence ratios (PRs, 95% confidence intervals) for CESD scores of 16–24 comparing the stages of the early menopausal transition (MT), late MT and post-menopause to pre-menopause was 1.28 (1.16–1.42), 1.21 (1.05–1.38) and 1.58 (1.36–1.84), respectively. The multivariable-adjusted PRs for CESD scores ⩾ 25 comparing the stages of the early MT, late MT and post-menopause to pre-menopause were 1.31 (1.11–1.55), 1.39 (1.12–1.72), 1.86 (1.47–2.37), respectively. In addition, the multivariable-adjusted PRs for suicidal ideation comparing the early MT, late MT and post-menopause stages to the pre-menopause stage were 1.24 (1.12–1.38), 1.07 (0.93–1.24) and 1.46 (1.25–1.70) (p for trend Conclusions These findings indicate that the prevalence of depressive symptoms and suicidal ideation increases with advancing menopausal stage, even pre-menopause.

Objective This study aimed to compare the efficacy and safety of escitalopram, vortioxetine, and desvenlafaxine for acute treatment of major depressive disorder (MDD) with cognitive complaint (CC).Methods A total of 129 patients with MDD who also complained of CC were randomized evenly to either escitalopram, vortioxetine, or desvenlafaxine group and underwent a multi-center, six-week, rater-blinded, and head-to-head comparative trial. Differences in depressive symptoms following treatment were measured using the Hamilton Depression Rating Scale (HAMD) and the Montgomery-Åsberg Depression Rating Scale (MADRS). Subjective cognitive function and the presence of adverse events were assessed.Results The three antidepressant treatment groups did not show significant differences in the improvement of depressive symptoms as measured by HAMD and MADRS. Desvenlafaxine treatment was associated with a superior treatment response rate in depressive symptoms compared to vortioxetine or escitalopram treatment. However, no significant differences were found in the remission rate of depressive symptoms. The three antidepressant treatment groups did not show significant differences in the improvement of CC. Adverse profiles of each treatment group were tolerable, with no significant differences.Conclusion In acute antidepressant treatment for MDD with CC, escitalopram, vortioxetine, and desvenlafaxine presented similar efficacy in relief of depressive symptoms; however, desvenlafaxine was associated with a superior treatment. Further studies are needed to confirm these results by investigating the therapeutic efficacy and safety profile of long-term antidepressant treatment of MDD with CC (Clinical Trial Registry, http://cris.nih.go.kr/cris/en/: KCT0002173).

Objective The aim of this study was to identify work stress associated with the development of suicidal ideation with a focus on gender and age differences among Korean employees. Methods The data of 95 356 healthy employees aged >18 years who had undergone at least two comprehensive health examinations at Kangbuk Samsung Hospital Health Screening Center, South Korea, were analyzed. Risk of suicidal ideation was assessed using a self-reported questionnaire examining suicidal ideation during the past year. Work stress was measured using the Korean Occupational Stress Scale-Short Form. A Cox proportional hazards model was used to examine relationship between work stress and suicidal ideation. Considering gender and age differences in the association between work stress and suicidal ideation, the data were stratified by gender and age groups. Results During 289 706 person-years of follow-up, suicide ideation was identified in 3 460 participants. For male workers, high job demands and lack of reward were associated with the risk of suicidal ideation in young adults and midlife decade group. Job insecurity was associated with the risk of suicidal ideation in midlife decade and middle-aged and older adulthood. Organizational injustice was associated with the risk of suicidal ideation in middle-aged and older adulthood. Discomfort in an organizational climate was associated with the development of suicidal ideation in all age groups. For female workers, organizational injustice and discomfort in an organizational climate were associated with the risk of suicidal ideation in early adulthood. Conclusion The results suggested that certain work stressors are risk factors of suicidal ideation. Gender and age differences in components of work stress associated with suicidal ideation were also observed.

This study examined the validity and reliability of the Korean version of the Generalized Anxiety Disorder-7 (GAD-7) scale. The GAD-7 was standardized with data from 112 patients at a psychiatric outpatient clinic. The GAD-7 revealed high internal consistency, good test-retest reliability, and convergent validity. The ROC analysis resulted in poor sensitivity and specificity for detecting anxiety disorders in a psychiatric setting. The GAD-7 may not be useful in diagnosing anxiety disorders in a psychiatric setting, even though it appears to be a reliable, efficient, and valid measurement tool for evaluating anxiety symptoms.

This chapter reviews the roles of cytokines and glial cells in chronic pain and in psychiatric disorders, especially depression. One important role of cytokines is in communicating between activated glia and neurons, at all levels of the nervous system. This process of neuroinflammation plays important roles in pain and depression. Cytokines may also directly regulate neuronal excitability. Many cytokines have been implicated in both pain and psychiatric disorders, including interleukin-1β‎ (IL-1β‎), tumor necrosis factor-α‎, and IL-6. More generally, an imbalance between type 1, pro-inflammatory cytokines and type 2, anti-inflammatory cytokines has been implicated in both pain and psychiatric disorders. Activation of the sympathetic nervous system can contribute to both pain and psychiatric disorders, in part through its actions on inflammation and the cytokine profile.

Aims To evaluate the bidirectional relationship between blood pressure (BP) and depressive symptoms using a large prospective cohort study. Methods Prospective cohort study was performed in 276 244 adults who participated in a regular health check-up and were followed annually or biennially for up to 5.9 years. BP levels were categorised according to the 2017 American College of Cardiology and American Heart Association hypertension guidelines. Depressive symptoms were assessed using Centre for Epidemiologic Studies-Depression (CESD) questionnaire and a cut-off score of ≥25 was regarded as case-level depressive symptoms. Results During 672 603.3 person-years of follow-up, 5222 participants developed case-level depressive symptoms. The multivariable-adjusted hazard ratios (HRs) [95% confidence interval (CI)] for incident case-level depressive symptoms comparing hypotension, elevated BP, hypertension stage 1 and hypertension stage 2 to normal BP were 1.07 (0.99–1.16), 0.93 (0.82–1.05), 0.89 (0.81–0.97) and 0.81 (0.62–1.06), respectively (p for trend p for trend p for trend Conclusions In this large cohort study of young and middle-aged individuals, higher BP levels were independently associated with a decreased risk for developing case-level depressive symptoms and depressive symptoms were also associated with incident hypertension. Further studies are required to elucidate the mechanisms underlying the bidirectional association between BP levels and incident depression.

Background Recently, neuroinflammation and the immune-kynurenine pathway have received increased attention in the psychoimmunology field of major depressive disorder (MDD), while studies related to anxiety disorders have been very limited. Objective This study reviewed possible mechanisms by which stress or inflammation modulate anxiety through tryptophan metabolism and the kynurenine pathway. Methods Relevant literature was identified through a search of MEDLINE via PubMed. Results Accumulating evidence has indicated the modulatory effects of the immune-kynurenine pathway on anxiety. The tryptophan catabolites (TRYCATs) in the kynurenine pathway imbalanced by stress or inflammation induce serotonin and melatonin deficiency, making anxiety reactions more sensitive. In addition, TRYCATs cause or sustain anxiety by acting as endogenous anxiogens or anxiolytics, an NMDA agonist or antagonist, or a free radical generator. Conclusion We hope that our understanding of the psychoimmunological mechanisms of anxiety will be expanded and anxiety-related studies will receive greater attention.

This study was performed to examine the elements that cause suicidal ideation to develop into a suicide attempt by comparing the factors related to suicidal ideation and attempt. The subjects in the study were 5982 employees, who received mental health screening from January 2016 to December 2019 in Korea. Multivariate binary logistic regression analysis was performed with suicidal ideation and suicide attempt as dependent variables respectively. While suicidal ideation was associated with both moderate and severe grades of depression and alcohol consumption, only severe grades of depression and alcohol consumption were associated with suicide attempts. Among family, interpersonal, work-related, and financial stress, which were significant predictors of suicidal ideation, only family stress predicted suicide attempts. Whereas dissatisfaction with the present, regret for the past, and hopelessness for the future were all predictors for suicidal ideation, only regret for the past was a significant predictor of suicide attempts. The distinctive impact of family stress on suicide attempts suggests that family support can play a pivotal role in suicide prevention, and the significant impact of regret for the past on suicide attempts indicates the need for a cognitive approach in a high-risk population. Finally, the substantial impact of alcohol on suicide attempts compared to suicidal ideation suggests the importance of alcohol regulation in suicide prevention.

Objective This study was aimed at evaluating the diagnostic validity of the Korean version of the Clinically Useful Depression Outcome Scale (CUDOS) with varying follow-up in a typical clinical setting in multiple centers. Methods In total, 891 psychiatric outpatients were enrolled at the time of their intake appointment. Current diagnostic characteristics were examined using the Structured Clinical Interview for DSM-IV (41% major depressive disorder). The CUDOS was measured and compared with three clinician rating scales and four self-report scales. Results The CUDOS showed excellent results for internal consistency (Cronbach’s α, 0.91), test-retest reliability (patients at intake, r=0.81; depressed patients in ongoing treatment, r=0.89), and convergent and discriminant validity (measures of depression, r=0.80; measures of anxiety and somatization, r=0.42). The CUDOS had a high ability to discriminate between different levels of depression severity based on the rating of Clinical Global Impression for depression severity and the diagnostic classification of major depression, minor depression, and non-depression. The ability of the CUDOS to identify patients with major depression was high (area under the receiver operating characteristic curve=0.867). A score of 20 as the optimal cutoff point was suggested when screening for major depression using the CUDOS (sensitivity=89.9%, specificity=69.5%). The CUDOS was sensitive to change after antidepressant treatment: patients with greater improvement showed a greater decrease in CUDOS scores (p

Psychiatric disorders are too multifactorial to be defined as a primarily inflammatory disorder, and increased inflammatory response is not specific to mental disorder only. Numerous factors are involved in neuroinflammation, and there also are many confounding variables, making it difficult to obtain consistent outcomes. Therefore, it is necessary to specify genetic, physiological, and epidemiological attributes of particular population groups vulnerable to inflammatory response as well as the disease subtypes. As of now, definitive inflammatory markers for psychiatric disorders have not been identified, but they could be very useful in patients with minimal vulnerability. In addition, it is possible to use inflammatory markers as depression biomarkers in subtypes of depression, which can serve as bases to develop medications to treat the disorder.

The aim of this study was to identify gender- and age-specific occupational stress associated with depressive symptoms among Korean employees. Data of 73,014 employees aged 18 and above who had undergone comprehensive health examinations at Kangbuk Samsung Hospital Health Screening Center, South Korea, in January 2012 and who were followed up until December 2017 were collected, and 63,959 (participation rate: 87.59%, men: 50,413, women: 13,546) were finally analyzed. A Cox proportional hazards model was used to estimate the hazard ratios and 95% confidence intervals of the relationship between occupational stress and depressive symptoms. In light of gender and age differences in the association between occupational stress and depressive symptoms, interaction and stratification by gender and age groups were tested. During 238,630 person-years of follow-up, case-level depressive symptoms developed in 4227 participants (an incident rate of 1.8%). There were gender differences in the relationship between job stress and incident depressive symptoms. For men, high job demand, job insecurity, lack of reward, and discomfort in their organizational climate were associated with incident depressive symptoms in all age groups. Insufficient job control was associated with the development of depressive symptoms only in midlife and organizational injustice only in early adulthood. For women, the results for high job demand, organizational injustice, and discomfort in an organizational climate were associated with the onset of depressive symptoms from early adulthood to the midlife decade. The results suggest gender and age differences in the relationship between occupational stress and incident depressive symptoms.

Background: The relationship between blood pressure (BP) level and depression remains controversial. We evaluated the bidirectional relationship between BP and depressive symptoms using a large prospective cohort study. Methods: Prospective cohort study was performed in 172,102 adults who participated in a regular health checkup and were followed annually or biennially for up to 5.9 years. BP levels were categorized according to the 2017 American College of Cardiology and American Heart Association hypertension guidelines. Depressive symptoms were assessed using Center for Epidemiologic Studies-Depression (CESD) questionnaire and a cut-off score of ≥25 was regarded as depression. Findings: During 672,603.3 person-years of follow-up, 5,222 participants developed depression. The multivariable-adjusted hazard ratios (HRs) [95% confidence interval (CI)] for incident depression comparing hypotension, elevated BP, hypertension stage 1, and hypertension stage 2 to normal BP were 1.07 (0.99-1.16), 0.92 (0.82-1.05), 0.88 (0.80-0.96) and 0.77 (0.58-1.01), respectively (p for trend

Psychiatric disorders are too multifactorial to be defined as a primarily inflammatory disorder, and increased inflammatory response is not specific to mental disorder only. Numerous factors are involved in neuroinflammation, and there also are many confounding variables, making it difficult to obtain consistent outcomes. Therefore, it is necessary to specify genetic, physiological, and epidemiological attributes of particular population groups vulnerable to inflammatory response as well as the disease subtypes. As of now, definitive inflammatory markers for psychiatric disorders have not been identified, but they could be very useful in patients with minimal vulnerability. In addition, it is possible to use inflammatory markers as depression biomarkers in subtypes of depression, which can serve as bases to develop medications to treat the disorder.

We aimed to investigate the associations between genetic variants of the norepinephrine transporter gene (NET, also known as SLC6A2) and diagnosis of bipolar I disorder. In addition, we examined the relationship between the genetic variants and manic and psychotic symptoms in patients with bipolar I disorder. The three SNPs rs28386840, rs2242446, and rs5569 were genotyped in 326 patients: patients with bipolar I disorder (n = 160) and a control group (n = 166). Subsequently, multivariate logistic regression analysis adjusting for age and sex was conducted to identify independent influences of the SNPs on diagnosis of bipolar I disorder. A possible association between manic and psychotic symptoms and variants of SLC6A2 was also investigated in patients with bipolar I disorder. The rs28836840 SNP in the 5’-UTR of SLC6A2 was significantly associated with bipolar I disorder and with severity of manic and psychotic symptoms in this disorder. Individuals carrying a T allele in the rs28836840 SNP were likely to have a lower risk of bipolar I disorder or lower severity of manic and psychotic symptoms in patients with bipolar I disorder (bipolar I disorder diagnosis: OR = 0.643, 95% Cl = 0.468–0.883, p = 0.006; manic symptoms: β = −2.457, 95% Cl = −4.674 ~ −0.239, p = 0.031; psychotic symptoms: β = −2.501, 95% Cl = −4.700 ~ −0.301, p = 0.027). For the rs2242446 and rs5569 SNPs, there were no significant differences between patients with bipolar I disorder and those without. Our results revealed associations of the rs28386840 SNP with bipolar I disorder diagnosis and with severity of manic and psychotic symptoms. However, the findings reported here require replication in larger samples and various ethnic groups.

Research on the associations between the ratio of second-to-fourth digit lengths (2D:4D ratio) and psychological variables could be a useful method of confirming sex hormone effects on human behavior tendencies. This study investigated the correlations between the 2D:4D ratio and characteristics of temperament and character in an urban community population. We hypothesized that the 2D:4D ratio correlates more strongly with temperament than with character. A total of 728 healthy adults (330 men and 398 women) ranging in age from 20 to 45 years were tested. Subjects completed the Temperament and Character Inventory (TCI) and were examined by measuring the 2D:4D ratio using a direct measurement method. Correlations between the 2D:4D ratio and psychological characteristics were explored. For women only, significant positive correlations with the 2D:4D ratio were found in the TCI-Temperament dimension (TCI-T), particularly in the two subscales of harm avoidance scale. Women with higher 2D:4D ratios had higher fear of uncertainly scores (rpartial = 0.206, p = 0.028) and shyness with strangers scores (rpartial = 0.252, p = 0.024). The 2D:4D ratio shows stronger correlations with temperament than with character. A higher 2D:4D ratio of woman is expected to indicate harm avoidance.

We developed bifacial transparent back contact (TBC) hydrogenated amorphous silicon (a-Si:H) semi-transparent glass-to-glass photovoltaic (PV) modules with emotionally inoffensive and esthetically pleasing colors have been developed by combining the transparent back contact and color of the back glass. Due to the high series resistance of the transparent back contact, the bifacial TBC a-Si:H semi-transparent PV modules had a lower rated power after light soaking than the monofacial opaque (metal) back contact (OBC) a-Si:H semi-transparent PV modules fabricated using the additional laser scribing patterns. However, the TBC a-Si:H semi-transparent PV module produced a higher annual electrical energy output than the OBC a-Si:H semi-transparent PV module thanks to bifacial power generation during the outdoor field test. In particular, the performance ratio of the TBC a-Si:H semi-transparent PV module measured at the optimal tilt angle of 30° surpassed its simulated prediction by a drastically high value of 124.5%. At a higher tilt angle of 85°, bifacial power generation produced a higher deviation between the measured and simulated annual performance of the TBC a-Si:H semi-transparent PV module. Since the reflected albedo has a tendency to increase toward higher tilt angles, bifacial power generation can compensate for the loss of lower direct plane-of-array irradiation at a higher tilt angle. Therefore, the TBC a-Si:H semi-transparent PV module is suitable for the vertically mounted building integrated photovoltaic modules for use in curtain walls, facades, roofs and traffic noise barriers by harvesting reflected and illuminated light.

Vitamin D deficiency has been reported to be associated with various neuropsychiatric disorders. However, there are few studies addressing deficient vitamin D levels and suicidal ideation.Serum vitamin D of 157,211 Korean adult participants were measured using electrochemiluminescence immunoassay. A self-reported questionnaire was used to assess whether participants experienced suicidal ideation. Logistic regression model was used to estimate the odds ratio (OR) of suicidal ideation according to vitamin D levels. The regression was adjusted for a range of covariates.Compared with sufficient vitamin D levels (≥20 ng/mL), deficient vitamin D levels (10 ng/mL) were significantly associated with the risk of suicidal ideation (OR = 1.138, 95% Cl = 1.027-1.262). However, the OR of suicidal ideation was not significantly different between the vitamin D insufficient group (10-19.99 ng/mL) and sufficient group (≥20 ng/mL) (OR = 0.988, 95% Cl = 0.932-1.047).Deficient vitamin D levels were significantly associated with the risk of suicidal ideation. However, the risk of suicidal ideation was not significantly different between the vitamin D insufficient group and sufficient group.

Introduction Shift work is known to have a negative impact on a wide range of health problems such as sleep disturbance, cognitive impairment, and emotional disorders (e.g., anxiety and depression). It is important to understand underlying mechanisms for negative impact of shift work on health problems. This study aimed to investigate psychological and neural mechanisms associated with shift work. Methods Thirty six shift workers (28 females, age = 29.9 ± 7.4) and 35 non-shift workers (20 females, age = 30.5 ± 5.5) participated in this study. They were performing the word Stroop task during fMRI scanning. This task included sleep-related words and negative words to investigate neural substrates associated with sleep-related information and emotional information processing. Neutral words were included as control stimuli. The participants also completed questionnaires assessing sleep-related problems such as Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale, and emotion-related problems such as Beck Depression Inventory and Beck Anxiety Inventory. Two-sample t-tests were conducted to find group differences in self-report measures and neural response to sleep-related words and negative words compared to neutral words. Results Relative to non-shift workers, shift workers showed greater sleep disturbance (i.e., higher PSQI), but they did not show any evidence of emotion-related problems. Shift workers also demonstrated greater neural response to negative words (vs. neutral words) in several prefrontal regions (e.g., dorsal anterior cingulate cortex and dorsolateral prefrontal cortex), anterior insula and caudate compared to non-shift workers. However, shift workers did not show significantly different neural response to sleep-related words (vs. neutral words) compared to non-shift workers. Conclusion The result from this study provides supporting evidence that shift work is associated with subjective sleep disturbance. Shift workers’ heightened neural response to negative information may reflect their increased sensitivity to negative information, that may contribute to sleep disturbance. Support Brain Research Program through the National Research Foundation of Korea funded by the Ministry of Science, ICT & Future Planning (Study No.: 2016M3C7A1904338 and NRF-2018R1D1A1B07049704).

Psychiatric patients with many episodes that do not respond satisfactorily to numerous sequential treatment regimens were included in the treatment resistance studies. Most studies have, however, used a post hoc experimental design that failed to determine the association between biomarkers and the initial risk of treatment-resistant psychiatric disorder (TRP). Such post hoc experimental design can be regarded only as a consequence of having treatment resistance, rather than being a causal risk factor for it. Although informative, data derived from such studies often do not allow for a distinction to be made between cause and effect. To deal with this problem, it is most ideal to enroll untreated patients (those who were diagnosed but have not yet undergone treatment) as study subjects. In this chapter, the authors will review methodological considerations to uncover initial biological risk factors for TRP and propose a better study design for future research by discussing the shortcomings of the traditional study design.

OBJECTIVE We aimed to develop the clinical guideline for headache by the systematic review and synthesis of existing evidence-based guidelines. The purpose of developing the guideline was to improve the appropriateness of diagnosis and treatment of headache disorder, and consequently, to improve patients' pain control and quality of life. The guideline broadly covers the differential diagnosis and treatment of tension-type headache, migraine, cluster headache, and medication-overuse headache. METHODS This is a methodological study based on the ADAPTE methodology, including a systematic review of the literature, quality assessment of the guidelines using the Appraisal of Clinical Guidelines for REsearch & Evaluation II (AGREE II) Instrument, as well as an external review using a Delphi technique. The inclusion criteria for systematic search were as follows: topic-relevant, up-to-date guidelines including evidence from within 5 years, evidence-based guidelines, guidelines written in English or Korean, and guidelines issued by academic institutions or government agencies. RESULTS We selected five guidelines and conducted their quality assessment using the AGREE II Instrument. As a result, one guideline was found to be eligible for adaptation. For 13 key questions, a total of 39 recommendations were proposed with the grading system and revised using the nominal group technique. CONCLUSION Recommendations should be applied to actual clinical sites to achieve the ultimate goal of this guideline; therefore, follow-up activities, such as monitoring of guideline usage and assessment of applicability of the recommendations, should be performed in the future. Further assessment of the effectiveness of the guideline in Korea is needed.

Background : Recent studies on the prospective association between metabolic syndrome (MetS) and depression have reported conflicting findings. Methods : A cohort study was performed with 115,223 middle-aged adults, free of depression at baseline, who underwent at least 2 comprehensive exams between 2012 and 2015. MetS was assessed according to the National Cholesterol Education Program Adult Treatment Panel III. The study endpoint was new onset of depression, defined as a Center for Epidemiologic Studies-Depression Scale score ≥ 16. Results : Over 253,451.6 person-years, 6,833 participants developed depression. When the participants with 0 MetS components were set as a reference, the multivariable-adjusted hazard ratio (HR, 95% confidence interval [CI]) for incident depression formed a U-shaped curve with the number of MetS components (p for trend = 0.229): 1 (1.07 [1.02–1.15]); 2 (0.92 [0.82–1.06]); 3 (0.85 [0.78–1.07]); 4 (1.16 [1.06–1.32]); and 5 MetS components (1.25 [1.10–1.54]). The presence or absence of MetS was not significant in new-onset depression. In examining potential clustering and synergistic effects of the constituent parts, waist circumference was the major driving factor of incident depression, and its relative excess risk due to interaction increased with the number of combinations. Limitations : We used a self-reported depression scale, and the follow-up period was relatively short. Conclusions : Future studies investigating the risk for incident depression should place more focus on the number of MetS abnormalities and specific MetS factors, such as waist circumference, than the presence or absence of MetS.

Although depression has generally been explained with monoamine theory, it is far more multifactorial, and therapies that address the disease's pathway have not been developed. In this context, an understanding of neuroinflammation and neurovascular dysfunction would enable a more comprehensive approach to depression. Inflammation is in a sense a type of allostatic load involving the immune, endocrine, and nervous systems. Neuroinflammation is involved in the pathophysiology of depression by increasing proinflammatory cytokines, activating the hypothalamus-pituitary-adrenal axis, increasing glucocorticoid resistance, and affecting serotonin synthesis and metabolism, neuronal apoptosis and neurogenesis, and neuroplasticity. In future, identifying the subtypes of depression with increased vulnerability to inflammation and testing the effects of inflammatory modulating agents in these patient groups through clinical trials will lead to more concrete conclusions on the matter. The vascular depression hypothesis is supported by evidence for the association between vascular disease and late-onset depression and between ischemic brain lesions and distinctive depressive symptoms. Vascular depression may be the entity most suitable for studies of the mechanisms of depression. Pharmacotherapies used in the prevention and treatment of cerebrovascular disease may help prevent vascular depression. In future, developments in structural and functional imaging, electrophysiology, chronobiology, and genetics will reveal the association between depression and brain lesions. This article aims to give a general review of the existing issues examined in the literature pertaining to depression-related neuroinflammatory and vascular functions, related pathophysiology, applicability to depression treatment, and directions for future research.

This study investigated the dose-response relationship between physical activity and depression. We collected data from 99,846 participants who had no medical contraindications to exercise. Using the short-form Korean version of the International Physical Activity Questionnaire, total physical activity was computed in metabolic equivalents (METs). We used the Center for Epidemiologic Studies Rating Scale for Depression to assess depressive symptoms and set a cut off score of 21. Logistic regression analyses were used to determine any relationships. To assess the effect of sex difference on the association between physical activity and depression, we stratified our data by sex. Compared with the sedentary group (0-600 METs-min/week), 1-15 times the recommended minimum physical activity was associated with a significantly lower risk of depression in all adults. The optimal range for a lower risk of depression was 2-3 times the recommended minimum. After stratifying our data by sex, we found that optimal ranges were 10-15 times the recommended minimum physical activity in men and 3-5 times in women. This study established a U-shaped dose-response relationship between physical activity and depression. The optimal range and upper threshold for anti-depression effect of physical activity were higher in men than in women.

Color design for large-area hydrogenated amorphous silicon (a-Si:H) semi-transparent glass-to-glass (GTG) photovoltaic (PV) modules has been studied for the application to building integrated PV (BIPV) modules. Three-dimensional color space of CIE (Commission Internationale de l'eclairage) L * a * b * (CIELAB) is adopted for a systematic color analysis. Three kinds of design configurations are invented by combining the transparency of back contacts and laser patterning techniques. In addition, the realization of emotionally stable and esthetic color is challenged using color back encapsulating materials. Transparent back contact (TBC)-type modules with green color are fabricated via the most simplified processes without sacrificing any active area. Bright and esthetic hybrid-type modules are also fabricated using additional laser-scribed patterns and blue encapsulating film. It is found that opaque back contact (OBC)-type module design is the best way to achieve target color together with the highest conversion efficiency. Because color of the back encapsulating materials does not deteriorate the conversion efficiency, the developed design concepts are promising options for large-area semi-transparent BIPV modules.

We have investigated the electrical energy yield of hydrogenated amorphous silicon (a-Si:H) single-junction and crystalline (c-Si) photovoltaic (PV) rooftop systems operated under distinct four seasons. The impact of the module type and installed tilt angle on the annual electrical energy yield has been monitored and then compared with the data predicted by the computer simulation. Despite a good temperature coefficient and less shading effect of a-Si:H single-junction modules, the energy output gain of the a-Si:H single-junction PV generator is only 2.7% compared to the c-Si PV generator installed using c-Si PV modules. It is inferred that a nominal rated power of the a-Si:H single-junction modules determined by an indoor light soaking test is not suitable for the design of PV systems operated under distinct four seasons. Thus, the nominal rated power of the a-Si:H single-junction PV modules should be determined through a proper outdoor exposure test considering thermal annealing and light soaking effects under various seasonal weather conditions. In addition, it is found that the performance of the Si-based PV rooftop systems operated under distinct four seasons could be improved by simply toggling the tilt angle considering the plane-of-array irradiance and snowfall effect.

Cognitive impairment in patients with depression has great clinical relevance, as depressed patients with cognitive impairment have more physical diseases, greater reduced social functionality, and, eventually, higher mortality. Although cognitive decline may simply be a symptom of depression, accurate assessment and treatment of cognitive impairment is crucial, as it is considered a key risk factor for the prognosis of possible neurocognitive disorders, such as Alzheimer’s disease. In this review, we investigated psychological and biological mechanisms of cognitive impairment in patients with depression and briefly discuss the methods to assess neurocognitive function in depression. Furthermore, we presented some issues about which to be cautious in the therapeutic setting.

Objective This study is a prospective observational study on 75 late-adolescent survivors of a large passenger ship accident from immediately after the accident to one year later. Methods Assessments of student survivors were conducted on day 2 and at months 1, 6, and 12. The PTSD Checklist (PCL), Patient Health Questionnaire-9 (PHQ-9), State subscale of the State and Trait Anxiety Inventory (STAI-S), Athens Insomnia Scale (AIS), and Brief Resilience Scale (BRS) were administered. Results When the assessments for day 2 and month 12 were compared, all the scales, except the PCL-avoidance subscale, showed a significant improvement in symptoms among males. However, among females, all the scales, except the PCL-re-experience subscale and the STAI-S, failed to show a significant improvement. All the symptoms for both males and females showed a pattern that decreased to the lowest level at month 1 (camp-based controlled intervention period), then increased at months 6 and 12 (voluntary individual treatment after returning to school). Conclusion The rapid deterioration of psychological symptoms was found during the chronic phase, when students returned to their daily routines and received voluntary individual therapy. There is a need to screen high-risk adolescents and be more attentive to them during this period.

Inflammation is not the only cause of depression and cannot explain its entire pathophysiology, but it is an important pathogenic factor that explains one possible mechanism of depression, with the kynurenine (KYN) pathway of tryptophan at its center. In particular, greater impairment seems to exist in the KYN pathway in inflammation-induced depression related to immunotherapy, autoimmune disease, and infection. In patients with these conditions, immunopharmacology is likely to be an important therapy. To develop this therapy, clear evidence of the immune-KYN pathway must be established via multiple types of experiments. This paper reviews the body of evidence, not only for the action of tryptophan (TRY) and consequent serotonin depletion, but also for the detrimental effects of TRY catabolites and the key enzymes in the KYN pathway that play important roles in the pathophysiology of inflammation-induced depression. In addition, this paper explores a potential treatment strategy for inflammation-induced depression using KYN metabolism.

Depressive disorder is a common mental illness and remains a major cause of morbidity worldwide. The present study, a cross-sectional, nationwide, population-based survey assessed the prevalence of depression in the general population of Korea through a random sampling of the non-institutionalized population for the Korea National Health and Nutrition Examination Survey (KNHANES) VI. The Patient Health Questionnaire (PHQ)-9 was first introduced into the KNHANES to detect depression. The point prevalence of depression (PHQ score of 10 or higher) was 6.7% (95% confidence interval [CI], 5.7–7.6) in 4,949 subjects. Based on the analysis using the diagnostic algorithm of the PHQ-9, the prevalence of major depressive disorder was 2.7% (95% CI, 2.2–3.3). Multiple logistic regression analysis, after adjusting the sociodemographic variables, also showed that the factors associated with depression were perceived stress and health status. This study reported for the first time that the point prevalence of depression screened using the PHQ-9 in this nationwide survey of the Korean population was similar to that of the western countries. As the KNHANES to detect depression is conducted biennially, further studies on the accumulated data are expected in the future., Graphical Abstract

Sickness absence has been regarded as an important indicator of workers' health and work productivity. This study is aimed to evaluate the association between depressive symptoms and sickness absence in workers of South Korea.We used nationwide cross-sectional survey data from 2889 individuals in the working population aged over 19 years in South Korea. Depressive symptoms were measured using Patient Health Questionnaire-9 (PHQ-9). Those respondents who scored above 10 on PHQ-9 were regarded as having depressive symptoms. Sickness absence was considered a binary variable with an absence of at least 1 day in the past month. The survey instrument contained questions about sociodemographic factors, lifestyle, work-related factors, and chronic illnesses. Logistic regression models were used to find odds ratios and confidence intervals.The prevalence of sickness absence was found to be overall 4.6%. The adjusted odds ratio of sickness absence with depressive symptoms (PHQ-9 score ≥ 10) was 3.63 (Confidence Interval: 2.13-6.20) after controlling of possible confounders. Compared to minimal depressive symptoms (PHQ-95), the differences between other types of severity of depressive symptoms (mild, moderate, and moderately severe) in terms of mean of all sickness absences were more significant.The sickness absence based on the memory of the respondent in this study may result in a recall bias.Incidence of at least 1 day of sickness absence per month increased the risk of depressive symptoms after controlling for the possible confounding factors in general working population. It may be necessary to consider strategies for assessing depression in the workers who take sick leaves.

OBJECTIVE Residual symptoms of depression are related to more severe and chronic course of functional impairment with higher risk of relapse. The objective of this study was to validate, and determine psychometric properties of the Korean version of Depression Residual Symptom Scale (KDRSS). METHODS A total of 203 outpatients with recent episode of major depression based on DSM-IV criteria were enrolled in this study. They had been treated with antidepressants and assessed by KDRSS, Hamilton Depression Rating Scale-24 (HDRS-24), and Montgomery-Asberg Depression Rating Scale (MARDS). The validity and reliability of KDRSS were assessed, including internal consistency reliability, concurrent validity, temporal stability, factorial validity, and discriminative validity. RESULTS Internal consistency (Cronbach's alpha=0.961), concurrent validity (MADRS: r=0.731, p

We developed high throughput, high efficiency 1.43 m 2 hydrogenated amorphous silicon (a-Si:H) single-junction photovoltaic (PV) modules using a two-step deposition for the intrinsic a-Si:H absorber with the high deposition rate of 0.41 nm/s. The developed module using the two-step deposition method leads to higher initial maximum power ( P max ) due to the reduced recombination loss at the p/i interface, compared to the a-Si:H single-junction PV module fabricated by the conventional one-step deposition with the low deposition rate of 0.20 nm/s. In addition, the developed module exhibits moderate light-induced degradation ratio of 26.1% in an outdoor exposure test with accumulated solar irradiance >380 kWh/m 2 . Thus, the comparable energy output gain is confirmed via a long-term outdoor field test. Consequently, superior throughput of the developed module over the conventional module is possible with comparable stabilized performance.

Development and comparison of spine-shaped phantoms generated by two different 3D-printing technologies, digital light processing (DLP) and Polyjet has been purposed to utilize in patient-specific quality assurance (QA) of stereotactic body radiation treatment. The developed 3D-printed spine QA phantom consisted of an acrylic body phantom and a 3D-printed spine shaped object. DLP and Polyjet 3D printers using a high-density acrylic polymer were employed to produce spine-shaped phantoms based on CT images. Image fusion was performed to evaluate the reproducibility of our phantom, and the Hounsfield units (HUs) were measured based on each CT image. Two different intensity-modulated radiotherapy plans based on both CT phantom image sets from the two printed spine-shaped phantoms with acrylic body phantoms were designed to deliver 16 Gy dose to the planning target volume (PTV) and were compared for target coverage and normal organ-sparing. Image fusion demonstrated good reproducibility of the developed phantom. The HU values of the DLP- and Polyjet-printed spine vertebrae differed by 54.3 on average. The PTV Dmax dose for the DLP-generated phantom was about 1.488 Gy higher than that for the Polyjet-generated phantom. The organs at risk received a lower dose for the 3D printed spine-shaped phantom image using the DLP technique than for the phantom image using the Polyjet technique. Despite using the same material for printing the spine-shaped phantom, these phantoms generated by different 3D printing techniques, DLP and Polyjet, showed different HU values and these differently appearing HU values according to the printing technique could be an extra consideration for developing the 3D printed spine-shaped phantom depending on the patient's age and the density of the spinal bone. Therefore, the 3D printing technique and materials should be carefully chosen by taking into account the condition of the patient in order to accurately produce 3D printed patient-specific QA phantom.

Brexpiprazole was approved for adjunctive treatment of major depressive disorder (MDD) in 2015. Because only a small number of randomized controlled trials have investigated the use of brexpiprazole in MDD, we performed a meta-analysis.We systematically searched literatures in PubMed, Cochrane Library database, EMBASE, Google Scholar, and clinicaltrials.gov up to January 2016. The primary efficacy measure was the mean change in total Montgomery-Åsberg Depression Rating Scale (MADRS) score from baseline. Secondary efficacy measures were the mean change in total Hamilton Rating Scale for Depression (17 items) score from baseline and the response (≥50% reduction in MADRS total score) and remission (MADRS total score ≤ 10 with ≥50% reduction) rates.Four studies fulfilled the inclusion criteria and were included in the analysis. Brexpiprazole showed superior efficacy over placebo with effect sizes (mean differences) of -1.76 (95% confidence interval [CI], -2.45 to -1.07) for MADRS and -1.21 (95% CI, -1.71 to -0.72) for the 17-item Hamilton Rating Scale for Depression. The risk ratios for response and remission were 1.57 (95% CI, 1.29-1.91) and 1.55 (95% CI, 1.22-1.96), respectively. The incidences of discontinuation due to adverse events, akathisia, and weight increase were higher in the brexpiprazole group than in the placebo group, with risk ratios of 3.44 (95% CI, 1.52-7.80), 3.39 (95% CI, 2.08-5.51), and 4.36 (95% CI, 2.45-7.77), respectively, and the incidence of akathisia was related to the brexpiprazole dose.Although our results suggest that brexpiprazole could be an effective adjunctive agent for MDD, they should be cautiously translated into clinical practice because the meta-analysis was based on only a handful of randomized controlled trials.

Objective The purpose of this study was to investigate the therapeutic effects of eye movement desensitization and reprocessing (EMDR) on post-traumatic growth (PTG). Methods This study was conducted using a sample of ten survivors of a large-scale maritime disaster that occurred in the Yellow Sea, South Korea, in April 2014. A total of eight EMDR sessions were administered by a psychiatrist at two-week intervals over a period of five months, starting two or three months after the accident. Post-Traumatic Growth Inventory (PTGI), Stress-Related Growth Scale (SRGS), Clinician-Administered PTSD Scale (CAPS), and Connor-Davidson Resilience Scale (CD-RISC) were measured before treatment, after sessions 4 and 8, and at three months after treatment completion. Results After three months from treatment completion, significant increases were observed in PTG (PTGI: Z(8)=-2.380, p=0.017; SRGS: Z(8)=-2.380, p=0.017) and resilience (CD-RISC: Z(8)=-2.386, p=0.017). A decrease in post-traumatic stress disorder (PTSD) level was also significant (CAPS: Z(8)=-2.176, p=0.030). The reduction of CAPS scores was correlated with increases of PTGI (rho=0.78, p=0.023) and SRGS (rho=0.79, p=0.020) scores. The changes in CAPS, PTGI, and SRGS scores between time point of end 8-session and three months follow-up was not significant (all p〉0.05). Subjects with higher pre-treatment CD-RISC scores showed more significant improvements in PTGI (rho=0.88, p=0.004) and SRGS (rho=0.83, p=0.010) scores after treatment than did those with lower pre-treatment CD-RISC scores. Conclusion EMDR therapy using standard protocol for trauma processing helped facilitating PTG in disaster survivors. To generalize these findings, further controlled studies comparing with other treatment modalities for PTSD are needed.

This study aimed at exploring the psychometric characteristics of the Korean Version of the Depression and Somatic Symptoms Scale (DSSS) in a clinical sample, and investigating the impact of somatic symptoms on the severity of depression. Participants were 203 consecutive outpatients with current major depressive disorders (MDD) or lifetime diagnosis of MDD. The DSSS was compared with the Montgomery-Åsberg Depression Rating Scale (MADRS) and the 17-items Hamilton Depression Rating Scale (HAMD). The DSSS showed a two-factor structure that accounted for 56.8% of the variance, as well as excellent internal consistency (Cronbach’s alpha = 0.95), concurrent validity (r = 0.44–0.82), and temporal stability (intraclass correlation coefficient = 0.79). The DSSS had a high ability to identify patients in non-remission (area under receiver operating characteristic [ROC] curve = 0.887). Maximal discrimination between remission and non-full remission was obtained at a cut-off score of 22 (sensitivity = 82.1%, specificity = 81.4%). The number of somatic symptoms (the range of somatic symptoms) and the scores on the somatic subscale (SS, the severity of somatic symptoms) in non-remission patients were greater than those in remission patients. The number of somatic symptoms (slope = 0.148) and the SS score (slope = 0.472) were confirmed as excellent predictors of the depression severity as indicated by the MADRS scores. The findings indicate that the DSSS is a useful tool for simultaneously, rapidly, and accurately measuring depression and somatic symptoms in clinical practice settings and in consultation fields., Graphical Abstract

Background:Previous studies suggest that there is a strong association between depression and cognitive decline, and that concurrent depressive symptoms in MCI patients could contribute to a difference in neurocognitive characteristics compared to MCI patients without depression. The authors tried to compare neurocognitive functions between MCI patients with and without depression by analyzing the results of neuropsychological tests.Methods:Participants included 153 MCI patients. Based on the diagnosis of major depressive disorder, the participants were divided into two groups: depressed MCI (MCI/D+) versus non-depressed MCI (MCI/D−). The general cognitive and functional statuses of participants were evaluated. And a subset of various neuropsychological tests was presented to participants. Demographic and clinical data were analyzed using Studentt-test orχ2test.Results:A total of 153 participants were divided into two groups: 94 MCI/D+ patients and 59 MCI/D− patients. Age, sex, and years of education were not significantly different between the two groups. There were no significant differences in general cognitive status between MCI/D+ and MCI/D− patients, but MCI/D+ participants showed significantly reduced performance in the six subtests (Contrasting Program, Go-no-go task, Fist-edge-palm task, Constructional Praxis, Memory Recall, TMT-A) compared with MCI/D− patients.Conclusions:There were significantly greater deficits in neurocognitive functions including verbal memory, executive function, attention/processing speed, and visual memory in MCI/D+ participants compared to MCI/D−. Once the biological mechanism is identified, distinct approaches in treatment or prevention will be determined.

Under conditions of increasing environmental uncertainty, firms` risk management become important. This study examines the impact of foreign currency derivative usage on firm value using 3,004 Korean non-financial firms from 2002 to 2007. The results showed that there was no significant relationship between foreign currency derivative usage and firm value for the whole period and from 2002 to 2004 when exchange rate was relatively less volatile. But form 2005 to 2007 when exchange rate was volatile, foreign currency derivative usage gave significant negative impact on firm value, whereas when contract value was used, the relatinship was significantly positive. These results might be come from the characteristics of contract value and fair value of foreign currency derivatives. increased firm value when contract value was used as foreign currency derivative usage measure. But when fair value was used, there was no significance. For control variables, major shareholders ownership and foreign blockholders ownership was positively related with firm value.