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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.

Objective The risk of suicide is assessed by identifying the relationship between alcohol-use patterns and suicidal ideation in Korean employees.Methods The study involved 13,858 employees who underwent workplace mental health screening at the Workplace Mental Health Institute of Kangbuk Samsung Hospital over a 6-year period between 2014 and 2019. Analysis was performed separately for Alcohol Use Disorders Identification Test-Korea (AUDIT-K) items related to the frequency/volume of alcohol consumption (items 1 to 3, AUDIT-C) and those regarding alcohol dependence/related problems (items 4 to 10, AUDIT-D/P). Subjects were then classified into three groups on the basis of the presence or absence of clinical depression and suicidal ideation. The groups’ sociodemographic factors and clinical features of depression, anxiety, and alcohol-use patterns were analyzed with a chi-square test as well as one-way analysis of variance, followed by a post hoc test using the Bonferroni correction.Results AUDIT-K and AUDIT-D/P scores were significantly associated with the presence or absence of clinical depression as well as the presence or absence of suicidal ideation (p

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 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.

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.

Despite the fact that the lifetime and yearly prevalence rates of mental illness continue rising, such diseases have only been acknowledged as involved in workplace health issue since the 2000s. Additionally, while the number of recognized cases of mental illnesses is rather low compared to their prevalence, they have a high likelihood of causing significant problems, including fatalities. Many workers are terrified of losing their jobs due to mental illness and therefore attempt to hide their mental health problems. For this reason, clinicians involved in occupational and environmental medicine should focus on interviews or screenings to identify such hidden mental health problems. More specifically, it would be helpful to evaluate job stress and depression in workplaces to ensure appropriate preventive actions and thereby reduce the prevalence of mental illness. Job stress not only causes mental illness and dissatisfaction with work, but also can increase the prevalence and morbidity of medical diseases, as well as other physical health problems. Depression is a major contributor to work loss and absence with effects surpassing almost all of the chronic medical disorder. These facts show why measure of job stress and depression should be highlighted in the occupational settings. This article introduces a variety of assessment tools to examine mental health, particularly stress and depression, in workplaces. These tools can be used by clinicians or professionals involved in the mental health, occupational safety, or health service fields for running diagnostics or screening tests.

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.

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.

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

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

The limited effects of currently available antidepressants are becoming an urgent issue in depression research. It takes a long time to determine treatment effects, and the overall remission rate is low. Although we expect the development of non-monoamine antidepressants in the near future, efforts in this regard over the past several decades have not yet been compensated. Thus, researchers and clinicians should clarify the neurobiological mechanisms of integrated modulators that regulate changes in genes, cells, the brain, and behaviors associated with depression. In this study, we review molecular neurobiological theories and new treatments for depression. Beyond neuroanatomy and monoamine theory, we discuss cells and molecules, neural plasticity, neurotrophisms, endocrine mechanisms, immunological mechanisms, genetics, circadian rhythms, and metabolic regulation in depression. In addition, we introduce the possibility of new antidepressant drug development using protein translation signaling (mTOR) pathways.

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.

Objective Although Type D personality has been associated with the prognosis of various cardiac diseases, few studies have investigated the influence of Type D personality on the cardiac and psychiatric prognoses of patients with atrial fibrillation (AF). Methods Depression, anxiety, and quality of life were measured at baseline and 6 months. The recurrence of AF was measured during 1-year following radiofrequency catheter ablation (RFCA) for AF. The Kaplan-Meier method with log-rank tests were used to compare the cumulative recurrence of AF. ACox proportional hazard model was conducted to identify factors that contribute to the recurrence of AF. Results A total of 236 patients admitted for RFCA were recruited. Patients with a Type D personality had higher levels of depression and anxiety and a poorer quality of life compared to controls. Although depression, anxiety, and quality of life had improved 6 months after RFCA, significant differences in psychiatric symptoms remained between patients with and without Type D personality. In the Cox models, the type of AF was the only factor that influenced the recurrence of AF. Conclusion Our results suggest that Type D personality predominately influences psychological distress in patients with AF, but not the recurrence of AF.

Objective A community survey was performed to investigate the factors and perspectives associated with happiness among the elderly in Korea (≥60 years). Methods Eight hundred volunteers selected from participants in the Ansan Geriatric study (AGE study) were enrolled, and 706 completed the survey. The Happiness Questionnaire (HQ), which asks four questions about happiness, was administered. To explore the relationship between happiness and depression, the Geriatric Depression Scale (GDS) and the Beck Depression Inventory (BDI) also were administered. Results The participants' average level of happiness, determined using a 100-mm visual analogue scale (VAS) of the HQ, was 64.7±26.0. The happiest situations for most people were "getting together with family" (23.8%) and "living in peace with family members (well-being)" (13.2%). Frequent reasons for not being happy were "worsened health condition" (28.7% of the not-happy group), "economic problems of their own" (16.5%), and "economic problems of their children" (14.8%). The participants' choices regarding the essential conditions for happiness were "good health" (65.3%) and "being with family" (20.5%). The BDI and GDS scores were negatively related to the happiness score. A preliminary scale [Happy (Haeng-Bok, 幸福) aging scale] based on the HQ for measuring the happiness level of the Korean elderly was suggested for follow-up studies. Conclusion The most important factors determining the happiness of the community-dwelling elderly in Korea were good family relationships, economic stability, and good health. A higher depression score negatively impacted happiness among Korean elders. Further studies on the factors in their happiness are required.

Depression results from changes in the central nervous system (CNS) that may result from immunological abnormalities. The immune system affects the CNS through cytokines, which regulate brain activities and emotions. Cytokines affect two biological systems that are most associated with the pathophysiology of depression: The hypothalamic-pituitary-adrenal axis and the catecholamine/sympathetic nervous system. Neuroinflammation and cytokines affect the brain signal patterns involved in the psychopathology of depression and the mechanisms of antidepressants, and they are associated with neurogenesis and neural plasticity. These observations suggest that neuroinflammation and cytokines might cause and/or maintain depression, and that they might be useful in the diagnosis and prognosis of depression. This psychoneuroimmunologic perspective might compensate for some of the limitations of the monoamine theory by suggesting that depression is a result of a failure to adapt to stress and that inflammatory responses and cytokines are involved in this process. In this review, the interactions of cytokines with the CNS, neuroendocrine system, neurotransmitters, neurodegeneration/neurogenesis, and antidepressants are discussed. The roles of cytokines in the etiology and psychopathology of depression are examined. The use of cytokine inhibitors or anti-inflammatory drugs in depression treatment is explored. Finally, the significance and limitations of the cytokine hypothesis are discussed.