Understanding the Fluctuations in Korea's Suicide Rates: A Change-Point Analysis and Interrupted Time Series Analysis.

BACKGROUND: Korea has witnessed significant fluctuations in its suicide rates in recent decades, which may be related to modifications in its death registration system. This study aimed to explore the structural shifts in suicide trends, as well as accidental and ill-defined deaths in Korea, and to analyze the patterns of these changes. METHODS: We analyzed age-adjusted death rates for suicides, deaths due to transport accidents, falls, drowning, fire-related incidents, poisonings, other external causes, and ill-defined deaths in Korea from 1997 to 2021. We identified change-points using the 'breakpoints' function from the 'strucchange' package and conducted interrupted time series analyses to assess trends before and after these change-points. RESULTS: Korea's suicide rates had three change-points in February 2003, September 2008, and June 2012, characterized by stair-step changes, with level jumps at the 2003 and 2008 change-points and a sharp decline at the 2012 change-point. Notably, the 2003 and 2008 spikes roughly coincided with modifications to the death ascertainment process. The trend in suicide rates showed a downward slope within the 2003-2008 and 2008-2012 periods. Furthermore, ill-defined deaths and most accidental deaths decreased rapidly through several change-points in the early and mid-2000s. CONCLUSION: The marked fluctuations in Korea's suicide rate during the 2000s may be largely attributed to improvements in suicide classification, with potential implications beyond socio-economic factors. These findings suggest that the actual prevalence of suicides in Korea in the 2000s might have been considerably higher than officially reported.

Psychological and Personality Characteristics Associated With COVID-19 Vaccination Behavior in Korean General Population.

BACKGROUND: This study characterized coronavirus disease 2019 (COVID-19) vaccination behavior in the Korean general population using cluster analysis and explored related psychological factors. METHODS: We categorized 1,500 individuals based on their attitudes toward COVID-19 vaccination using hierarchical clustering and identified their level of vaccine acceptance. We examined the associations between vaccine acceptance and behavioral and psychological characteristics. RESULTS: Clustering revealed three groups according to vaccine acceptance: 'totally accepting' (n = 354, 23.6%), 'somewhat accepting' (n = 523, 34.9%), and 'reluctant' (n = 623, 41.5%). Approximately 60% of all participants who belonged to the 'totally accepting' and 'somewhat accepting' groups were willing to receive a COVID-19 vaccine despite concerns about its side effects. High vaccine acceptance was associated with older age, regular influenza vaccination, and trust in formal sources of information. Participants with high vaccine acceptance had higher levels of gratitude, extraversion, agreeableness, and conscientiousness, and lower levels of depression, anxiety, and neuroticism. CONCLUSIONS: People weighed the benefits of COVID-19 vaccination against the risk of side effects when deciding to receive the COVID-19 vaccine. Our findings also indicate that this vaccination behavior may be affected by coping mechanisms and psychological factors.

Longitudinal symptom network structure in first-episode psychosis: a possible marker for remission.

BACKGROUND: Network approach has been applied to a wide variety of psychiatric disorders. The aim of the present study was to identify network structures of remitters and non-remitters in patients with first-episode psychosis (FEP) at baseline and the 6-month follow-up. METHODS: Participants (n = 252) from the Korean Early Psychosis Study (KEPS) were enrolled. They were classified as remitters or non-remitters using Andreasen's criteria. We estimated network structure with 10 symptoms (three symptoms from the Positive and Negative Syndrome Scale, one depressive symptom, and six symptoms related to schema and rumination) as nodes using a Gaussian graphical model. Global and local network metrics were compared within and between the networks over time. RESULTS: Global network metrics did not differ between the remitters and non-remitters at baseline or 6 months. However, the network structure and nodal strengths associated with positive-self and positive-others scores changed significantly in the remitters over time. Unique central symptoms for remitters and non-remitters were cognitive brooding and negative-self, respectively. The correlation stability coefficients for nodal strength were within the acceptable range. CONCLUSION: Our findings indicate that network structure and some nodal strengths were more flexible in remitters. Negative-self could be an important target for therapeutic intervention.

Risk and protective factors of depression in the general population during the COVID-19 epidemic in Korea.

BACKGROUND: The risk of depression has risen in the general population during the COVID-19 epidemic. This study was conducted to explore risk and protective factors associated with depression among the general population uninfected by COVID-19. METHODS: A cross-sectional study was conducted with 1,500 representative South Korean citizens aged 19-65 years through an anonymous online survey. Depression was defined as a Patient Health Questionnaire-9 score of 10 or higher. Other questionnaires included one measuring psycho-behavioural and social changes, and stress, due to COVID-19, a six-item version of the Gratitude Questionnaire (GQ-6), and a three-item version of the UCLA loneliness scale. RESULTS: Of the 1492 participants not infected by COVID-19, 312 (20.9%) exhibited depression. Multiple logistic regression analysis revealed that depression was positively associated with COVID-19-related stress and psycho-behavioural variables such as disturbances in eating and sleeping, younger age, smoking, underlying mental illness, and loneliness scale scores. In contrast, exercise three or more times per week and GQ-6 scale scores were inversely associated with depression. CONCLUSION: During the COVID-19 pandemic, maintaining daily routines including eating, sleeping, and regular exercise and focusing on gratitude may be important for the prevention of depression. In addition, more attention should be paid to vulnerable populations, including young people, those with mental illnesses, and smokers, who might be more susceptible to depression.

The association of gratitude with perceived stress among nurses in Korea during COVID-19 outbreak.

BACKGROUND: During the COVID-19 pandemic, nurses might experience added emotional stress. This study examined the relationship between gratitude and psychological stress to explore effective psychological support among nurses. METHODS: A cross-sectional survey assessed the level of psychological distress in 646 nurses in Gwangju, South Korea, using the Perceived Stress Scale-10 (PSS-10), Gratitude Questionnaire-6 (K-GQ-6), Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), and Maslach Burnout Inventory-General Survey (MBI-GS). Sociodemographic factors and COVID-19-related experiences were also examined. A linear regression model was used to determine the factors influencing perceived stress. RESULTS: The mean PSS-10 score was 19.0 ± 4.4. Linear regression analyses revealed that the MBI-GS-Exhaustion, PHQ-9, and GAD-7 scores were positively associated with perceived stress, while the MBI-GS-Professional efficacy score was inversely associated with perceived stress. Gratitude disposition using the K-GQ-6 score negatively predicted PSS-10 (ß = 0.829, p < 0.001). CONCLUSIONS: Psychological interventions that help cultivate gratitude and professional efficacy among nurses can help promote stress resilience throughout the course of the COVID-19 pandemic.

The Relationships among Media Usage Regarding COVID-19, Knowledge about Infection, and Anxiety: Structural Model Analysis.

BACKGROUND: We examined the effects of mass media usage on people's level of knowledge about coronavirus disease 2019 (COVID-19), fear of infection, prejudice towards infected people, and anxiety level. In addition, we investigated whether knowledge about COVID-19 can reduce fear, prejudice, and anxiety. METHODS: We performed an anonymous online survey in 1,500 residents aged 19-65 years between April 24 and May 5 of 2020. Anxiety level was assessed using the generalized anxiety disorder-7 scale. We used a questionnaire to investigate COVID-19-related media use, knowledge about COVID-19, fear of infection, and prejudice towards infected people. We analyzed the relationships among the variables using the structural equation model. RESULTS: Media use had significant effects on fear of infection, prejudice against infected people, and anxiety. Knowledge about COVID-19 had a significant protective effect on fear of infection, prejudice against infected people, and anxiety. However, the effect of media use on knowledge about COVID-19 was not statistically significant. There was a partial mediating effect of prejudice against infected people and fear of infection on media usage and anxiety. CONCLUSION: Our study demonstrated significant effects of mass media coverage regarding COVID-19 on fear, prejudice, and anxiety. While knowledge about COVID-19 could decrease fear, prejudice, and anxiety, the use of mass media did not enhance this knowledge. Medical societies should guide mass media reporting of COVID-19 and provide appropriate public education.

Association between the zinc finger protein 804A (ZNF804A) gene and the risk of schizophrenia and bipolar I disorder across diagnostic boundaries.

OBJECTIVES: In this study, we aimed to determine the role of genetic variations within the zinc finger protein 804A (ZNF804A) gene, a candidate for a psychosis risk-conferring gene, in the development of schizophrenia (SZ) and bipolar disorder (BP) in the Korean population. METHODS: A total of 921 patients with SZ, bipolar I (BP-I) and II (BP-II) disorder, and 502 control subjects participated in the study. Twenty-one tag single nucleotide polymorphisms (SNPs) across the genomic region of ZNF804A and seven reference SNPs based on previous reports were genotyped. We applied logistic regression analyses under additive, dominant and recessive models. RESULTS: Fifteen of the 28 SNPs showed a nominally significant association with at least one diagnostic group. However, none of these associations remained significant after false discovery rate (FDR) correction. As the trend of association was observed mostly in SZ and BP-I with similar patterns, we performed a post hoc analysis for the combined SZ and BP-I group. Five SNPs (rs2369595, rs6755404, rs10931156, rs12476147 and rs1366842) showed a significant association with an FDR-corrected P of <.05. CONCLUSIONS: This study supports a possible role of ZNF804A in the common susceptibility of major psychoses, and identified additional candidate variants of the gene in the Korean population.

Tardive dyskinesia and tardive dystonia with second-generation antipsychotics in non-elderly schizophrenic patients unexposed to first-generation antipsychotics: a cross-sectional and retrospective study.

This study investigates the clinical nature, prevalence rates, and associated factors of second-generation antipsychotic (SGA)-related tardive dyskinesia and tardive dystonia. To date, these subjects have not been thoroughly investigated.The subjects were 80 non-elderly schizophrenic patients who received SGAs for more than 1 year without any previous exposure to first-generation antipsychotics. Multiple (≥2) direct assessments of movement symptoms were performed. Hospital records longer than 1 recent year describing any observed tardive movement symptoms were reviewed.A current or history of tardive dyskinesia and/or tardive dystonia associated with SGA was identified in 28 (35%) subjects. These patients were being treated with risperidone (n = 15), amisulpride, olanzapine, aripiprazole, ziprasidone, or clozapine at the time of the onset of the movement symptoms. Tardive dyskinesia was mostly in the orolingual area, and the most frequently observed tardive dystonia was torticollis. The median interval between the first exposure to the SGA and the movement syndrome onset was 15 months for tardive dyskinesia and 43 months for tardive dystonia. A history of acute dystonia was significantly associated with tardive dystonia, and comorbid obsessive-compulsive syndrome was related to both tardive movement syndromes.This study indicates that more clinical attention and research efforts are needed regarding SGA-associated tardive movement syndromes, including a larger-scale prevalence assessment. This study is the first to indicate that a comorbid obsessive-compulsive syndrome might be an associated factor of tardive movement syndrome. The association warrants further investigation.

Lifetime experiences of hypomanic symptoms are associated with delayed and irregular sleep-wake cycle and seasonality in non-clinical adult samples.

OBJECTIVES: Disturbances of the sleep-wake cycle and seasonality have been reported in patients with bipolar disorder (BD). Considering that BD seems to be a spectrum condition in terms of clinical and biological characteristics, circadian and seasonal rhythm related to BD could be detected in non-clinical individuals with subthreshold bipolarity. The aim of this study was to screen past hypomanic symptoms in non-clinical samples and investigate their association with deviated sleep-wake cycle and seasonality. METHODS: Lifetime history of hypomanic symptoms was assessed with the Hypomania Checklist-32 (HCL-32). Circadian preference, variability of sleep-wake time and seasonal changes in mood and behavior were evaluated on a lifetime-basis in non-clinical adult samples (n=313), using the Composite Scale of Morningness (CSM), the Sleep Timing Questionnaire (STQ), and the Seasonal Pattern Assessment Questionnaire (SPAQ). RESULTS: Two subdomains of hypomanic symptoms were identified through factor analysis of HCL-32, i.e., "active/elated" factor and "irritable/risk-taking" factor. The HCL-32 total score (p<0.001) and the "active/elated" factor score (p=0.028) were weakly correlated only with seasonality, whereas the "irritable/risk-taking" factor score was associated not only with seasonality (p<0.001), but also with evening preference (p<0.001) and irregularity of sleep-wake times (p=0.001~0.011). CONCLUSION: Circadian and seasonal characteristics related to BD are also associated with a past history of hypomanic symptoms in non-clinical samples, especially "irritable/risk-taking" symptoms, suggesting the existence of subclinical presentation of BD and their biological traits.

The moderating role of circadian gene polymorphisms in the relationship between sleep disturbance and circulating lymphocyte subsets in colorectal cancer patients.

AIM: We investigated the impact of sleep disturbance on immune status in colorectal cancer (CRC) patients with consideration of the moderating role of circadian clock gene polymorphisms. METHODS: A prospective longitudinal study design was used to collect information regarding sleep disturbance. Blood samples for immunologic assays were obtained the day before the first (baseline) and last cycles of 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX) chemotherapy. Clinical sleep disturbance was compared between the two-time points using the Pittsburgh Sleep Quality Index (PSQI) global score. We analysed single-nucleotide polymorphisms in rs2278749, rs3749474, rs2291738, rs17031614, and rs2287161. The dependent variables included changes in the percentages of CD4+, CD8+, CD19+, and CD16/56+ lymphocytes between the two-time points. The results were analysed using moderated regression analysis; the p-values were adjusted using the false discovery rate. RESULTS: Among the 104 patients, no significant dyadic associations were observed between changes in lymphocyte percentages and the PSQI global score. However, the moderated regression analysis revealed five significant associations (rs2287161 with CD8+, rs2278749 and rs2291738 with CD19+, and rs17031614 with CD4+ and CD16/56+ lymphocytes). The inclusion of each interaction resulted in a significant increase (5.7-10.7%) in the variance explained by changes in lymphocyte percentage. CONCLUSION: Patients with specific circadian gene allele types may be more susceptible to immune dysregulation when experiencing sleep disturbances. Considering that sleep disturbance is a modifiable factor that can impact immune regulation, it is essential to prioritise the management of sleep disturbances in CRC patients receiving FOLFOX chemotherapy.

The Relationship Between Fast Food Consumption and Daily Lifestyle Changes During School Closures Following the COVID-19 Pandemic: A Cross-Sectional Study Among Adolescents in Korea.

OBJECTIVE: Increased fast food consumption can have adverse effects on health and well-being among adolescents, posing a significant public health concern. The school closures due to the coronavirus disease-2019 (COVID-19) pandemic have led to changes in eating patterns and disrupted a balance diet among adolescents. This study explored the factors associated with fast food consumption among adolescents during school closures due to the COVID-19 pandemic. METHODS: A total of 1,710 middle and high school students in Gwangju, South Korea participated in a cross-sectional survey. The self-administered questionnaire included items assessing dietary intake, physical activity, sleep, media use, and sociodemographic information. The Patient Health Questonnaire-9, Generalized Anxiety Disorder-7, and three item version of the UCLA Loneliness Scale were also administered. Multivariable logistic regression was used to examine the factors associated with increased fast food consumption. RESULTS: Approximately 34.6% of the surveyed adolescents reported increased fast food consumption during school closures, as well as increased sleep duration, increased sedentary behaviors including watching TV and using the internet, and reduced physical activity. Multivariable logistic regression analysis revealed that fast food consumption during school closures was associated with irregular patterns of main meals and sleep, decreased physical activity, increased internet use, and a lack of daytime adult supervision. CONCLUSION: Our results highlight the need for dietary and lifestyle monitoring and guidelines to promote health among adolescents, especially during school closures. In conclusion, nutrition intervention programs aiming to limit fast food consumption and enhance healthy dietary habits among adolescents during long-term school closures are warranted.

Inflammatory markers of symptomatic remission at 6 months in patients with first-episode schizophrenia.

Neuroinflammation contributes to the pathophysiology of various mental illnesses including schizophrenia. We investigated peripheral inflammatory cytokines as a biomarker for predicting symptomatic remission in patients with first-episode schizophrenia. The study included 224 patients aged 15-60 years who fulfilled the criteria for schizophrenia spectrum disorder with a treatment duration ≤6 months. Serum levels of tumor necrosis factor (TNF) -α, interferon-γ, interleukin (IL)-1α, IL-1ß, IL-6, IL-8, IL-10, and IL-12 were measured. Psychotic symptoms, depressive symptoms, and general functioning were assessed using the Positive and Negative Syndrome Scale, Beck Depression Inventory (BDI), Calgary Depression Scale for Schizophrenia, and Personal and Social Performance scale, respectively. Duration of untreated psychosis (DUP) was also recorded. We investigated the factors associated with remission for each sex in logistic regression analysis. In total, 174 patients achieved remission at the 6-month follow-up (females, 83.5%; males, 70.9%). Remission was associated with older age and lower BDI scores in male patients and with lower TNF-α levels and shorter DUP in female patients. Our findings suggest that peripheral inflammatory cytokines may impede early symptomatic remission in female patients with schizophrenia. In addition, depressive symptoms in males and long DUP in females may be poor prognostic factors for early remission in patients with first-episode psychosis.

The Effect of Fear of COVID-19 Infection and Anxiety on Loneliness: Moderated Mediation Effects of Gratitude.

OBJECTIVE: This study was conducted to identify factors related to loneliness during the coronavirus disease-2019 (COVID-19) pandemic and focused on how the fear of COVID-19 infection affects loneliness and the conditional effect of gratitude as a moderator in the relationship among the fear of COVID-19, anxiety, and loneliness. METHODS: For the analysis of this study, a survey was conducted among 1,500 individuals aged 19 to 69 years living in three metropolitan areas in South Korea. Questionnaires included sociodemographic data, psychological experience and stress associated with COVID-19, Generalized Anxiety Disorder Scale-7, UCLA Loneliness Scale-3, and Gratitude Questionnaire-6. An analysis was conducted by applying SPSS PROCESS macro models 4 and 7. RESULTS: First, anxiety mediated the relationship between the fear of COVID-19 infection and loneliness. Second, the effect of the fear of COVID-19 infection on loneliness through anxiety was moderated by gratitude. The higher the gratitude, the more the fear of COVID-19 infection is buffered in the path to anxiety, and the lower the indirect effect on loneliness. CONCLUSION: This suggests that in the context of the COVID-19 pandemic, interventions for psychological problems such as anxiety and loneliness can be carried out through gratitude, a significant protective variable.

Suicide and Non-Suicidal Self-Injury From Internet Addiction Among Korean Adolescents.

Objectives: This study examined the associations between Internet addiction and suicide and non-suicidal self-injury (NSSI) among South Korean adolescents. Methods: We conducted a cross-sectional study of 1694 Korean adolescents. The suicidal Ideation Questionnaire and Deliberate Self- Harm Inventories were used to identify high-risk suicide and NSSI groups, respectively. Internet addiction was assessed using the Internet Addiction Scale. Other questionnaires included sociodemographic data, perceived academic stress, and daily life-related factors. We also performed a logistic regression analysis using the high suicide risk and NSSI groups as dependent variables. Results: The high suicide risk and NSSI prevalence rates among participants were 11.8% and 28.3%, respectively. A multivariable logistic regression analysis revealed that Internet addiction is associated with higher suicide risk and NSSI. Additionally, being female and academic stress were significant suicide risk factors, while male participants had a higher NSSI prevalence. Conclusion: Our results suggest that monitoring adolescents' Internet use and providing education to prevent Internet addiction would lower high suicide and NSSI risk. Moreover, suicide and NSSI risk screening in adolescents with Internet addiction and providing suitable interventions will be essential for the preventing suicide and NSSI.

COVID-19 vaccine acceptance and related behavioral and psychological characteristics in individuals with mental disorders in Korea.

Objective: This study aimed to investigate COVID-19 vaccine acceptance and related factors in individuals with mental disorders in Korea. Methods: We surveyed 572 individuals with mental disorders about their attitudes toward COVID-19 vaccination using a 7-item self-rating questionnaire on vaccine acceptance and hesitancy. We categorized the respondents into groups based on their level of vaccine acceptance using hierarchical clustering. In addition, we evaluated the respondents' vaccination status and trust in sources of information regarding COVID-19 vaccines, and assessed their psychological characteristics using the Patient Health Questionnaire-9, Gratitude Questionnaire-6, and Big Five Inventory-10. Results: Clustering revealed three groups according to vaccine acceptance: 'totally accepting' (n= 246, 43.0%), 'somewhat accepting' (n= 184, 32.2%), and 'hesitant' (n= 142, 24.8%) groups. Three quarters of all participants, who belonged to the 'totally accepting' or 'somewhat accepting' groups, were willing to receive a COVID-19 vaccine despite concerns about its side effects. Individuals in the high vaccine acceptance group were older (F= 12.52, p< 0.001), more likely to receive the influenza vaccine regularly, and more likely to trust formal information sources. Additionally, they had higher levels of gratitude (F= 21.00, p< 0.001) and agreeableness (F= 4.50, p= 0.011), and lower levels of depression (χ2= 11.81, p= 0.003) and neuroticism (F= 3.71, p= 0.025). Conclusion: The present study demonstrated that individuals with mental disorders were generally willing to receive COVID-19 vaccination. However, they weighed its need and effectiveness against potential side effects before coming to a decision. It is important to understand the behavioral and psychological characteristics associated with vaccine acceptance, to effectively communicate its importance to individuals with mental disorders.

Association between suicidal ideation and cognitive function in young patients with schizophrenia spectrum disorder.

Introduction: Suicide is a major concern for patients with recent-onset schizophrenia. We hypothesized that preserved cognitive function might be associated with a higher level of suicidality in patients with schizophrenia. We investigated the associations between cognitive function and suicidal ideation (SI) in young patients recently diagnosed with a psychotic disorder. Methods: This study analyzed data from a naturalistic clinical cohort study that comprised 402 patients with schizophrenia spectrum disorder. Patients with a treatment duration of ≤5 years and an age range of 15-39 years were enrolled. Participants were categorized into two groups based on SI as assessed by the Columbia Suicidal Severity Rating Scale. We collected demographic and clinical data and administered psychiatric, neurocognitive, and social cognitive measures. Results: Among participants, 52% reported experiencing SI. Patients with SI were significantly younger and had a longer duration of untreated psychosis (DUP) than those without it. The Positive and Negative Syndrome Scale-general psychopathology score was significantly higher in the SI group. Scores on the Calgary Depression Scale for Schizophrenia, Perceived Stress Scale, Beck Depression Inventory (BDI), and Beck Hopelessness Scale were significantly higher among patients with SI, while scores on the Subjective Well-being Under Neuroleptics-Short Form and Brief Resilience Scale were significantly lower compared to those without it. Patients with SI demonstrated significantly higher scores on the verbal and visual learning test, false belief task, picture stories task, and Controlled Oral Word Association Test. They also completed the Trail Making Test (TMT) parts A and B in significantly less time than those without it. After adjusting for age, DUP, and scores on the BDI, group differences in scores on the verbal and visual learning tests, TMT (parts A and B), and the false belief task, and the picture story task remained significant. Discussion: Our results suggest that along with traditional risk factors, better cognitive function may also be a major risk factor for suicidality in patients with schizophrenia. Providing psychological support and cognitive interventions is essential for young patients with recent-onset schizophrenia spectrum disorders, particularly those with high levels of depression, hopelessness, perceived stress, low resilience, and good cognitive function.

Association study of 27 annotated genes for clozapine pharmacogenetics: validation of preexisting studies and identification of a new candidate gene, ABCB1, for treatment response.

OBJECTIVE: Pharmacogenetic studies on clozapine (CLZ) have provided meaningful insights but have shown redundancies owing to wide interindividual variability and insufficient replication. The present study was designed to validate hitherto suggested candidate genes on CLZ pharmacokinetics and pharmacodynamics and explore new markers through an integrative study. METHODS: Based on a literature review, a total of 127 variations in 27 candidate genes were selected and analyzed. Ninety-six schizophrenic patients of Korean ethnicity with constant CLZ dosing were recruited, and information on body weight and smoking habits was gathered, as well as plasma drug levels and treatment responses. RESULTS: Among the pharmacokinetic-related single nucleotide polymorphisms, rs2069521 and rs2069522 in CYP1A2 for CLZ/(dose/weight) and norclozapine/(dose/weight) and rs1135840 in CYP2D6 for norclozapine/CLZ showed borderline associations that were insignificant after correction for multiple testing. Regarding treatment response, significant associations were exhibited in rs7787082 and rs10248420 of ABCB1 (P = 0.0005 and P = 0.0013, respectively) even after correction, and the rs7787082 G and rs10248420 A alleles in ABCB1 were more frequently observed in nonresponders. We also observed a trend in the associations of rs13064530 in HRH1 and rs4938013 in DRD2/ANKK1 with treatment response. CONCLUSIONS: We could not convincingly replicate most of the previous studies, a result that is possibly due to modest association between the suggested genes. Rather, we found a new candidate gene, ABCB1, for treatment response, which may provide a hypothesis on the relationship between the blood-brain distribution of CLZ and its clinical efficacy.

Association of genetic variations in DTNBP1 with cognitive function in schizophrenia patients and healthy subjects.

The dystrobrevin-binding protein 1 gene (DTNBP1) has been regarded as a susceptibility gene for schizophrenia. Recent studies have investigated its role on cognitive function that is frequently impaired in schizophrenia patients, and generated inconsistent results. The present study was performed to elucidate effects of genetic variations in DTNBP1 on various cognitive domains in both schizophrenia patients and healthy subjects. Comprehensive neuropsychological tests were administered to 122 clinically stable schizophrenia patients and 119 healthy subjects. Based on positive findings reported in previous association studies, six SNPs were selected and genotyped. Compared to healthy subjects, schizophrenia patients showed expected lower performance for all of the cognitive domains. After adjusting for age, gender, and educational level, four SNPs showed a nominally significant association with cognitive domains. The association of rs760761 and rs1018381 with the attention and vigilance domain remained significant after applying the correction for multiple testing (P < 0.001). Similar association patterns were observed both, in patients and healthy subjects. The observed results suggest the involvement of DTNBP1 not only in the development of attention deficit of schizophrenia, but also in the inter-individual variability of this cognitive domain within the normal functional range.

Trends in suicide deaths before and after the COVID-19 outbreak in Korea.

We investigated the effect of the coronavirus disease-2019 (COVID-19) pandemic on suicide trends in Korea via a time-series analysis. We used Facebook Prophet to generate forecasting models based on the monthly numbers of suicide deaths in Korea between 1997 and 2018, validated the models by comparison with the 2019 numbers, and predicted the numbers of suicides in 2020. We compared the expected and observed numbers of suicides during the COVID-19 pandemic. The total numbers of suicides during the COVID-19 pandemic did not deviate from projections based on the pre-pandemic period. However, the number of suicides among women and those under the age of 34 years significantly exceeded the expected level. The COVID-19 pandemic did not increase the overall suicide rate significantly. However, suicides among women and young people increased, suggesting that the pandemic might drive more members of these groups to suicide. Further studies are needed to verify the long-term impact of the COVID-19 pandemic on suicide.

Decline in Hospital Visits by Patients with Schizophrenia Early in the COVID-19 Outbreak in Korea.

OBJECTIVE: This study investigated trends in hospital utilization by patients with schizophrenia during the first wave of the COVID-19 outbreak in Korea. METHODS: The Prophet algorithm was used to predict the monthly number of patients with schizophrenia in 2020 based on medical insurance data between 2010 and 2019. The projected expectations were compared with the actual number of patients receiving outpatient and inpatient treatment each month in the first half of 2020. We conduct interrupted time series analyses of short-term data to determine the significance of recent changes in the trend of hospital visits by patients with schizophrenia. RESULTS: The prediction model showed that the actual number of patients receiving treatment each month during the early COVID-19 outbreak decreased by up to 3.6% compared to the projected expectations. The interrupted time series model also revealed a significant change in hospital utilization compared to the year before the onset of COVID-19 in Korea (F = 8.961, p = 0.010). CONCLUSION: This suggests that many patients with schizophrenia were not receiving adequate treatment during the COVID-19 outbreak. A strategy should be developed to keep treating patients with schizophrenia during the COVID-19 pandemic.