OBJECTIVES: Considering large diversity of clinical presentation of schizophrenia, it is important to identify valid clinical subtypes or dimensions that might have homogeneous biological underpinning. The current study aimed to explore lifetime symptom-based dimensional phenotypes in patients with chronic schizophrenia, and to investigate their correlation with cognitive functions and other clinical characteristics. METHODS: Lifetime-based symptoms and additional clinical variables were measured using the Diagnostic Interview for Genetic Studies and the Schedule for the Deficit Syndrome in 315 clinically stable patients with chronic schizophrenia. Through principal components factor analysis, eight dimensional phenotypes were obtained. Comprehensive neuropsychological tests were administered for 103 out of 315 patients, and domain scores were calculated for cognitive domains defined in the MATRICS consensus battery. RESULTS: 'Non-paranoid delusion factor' including delusions of grandiose or religious nature, showed significant negative correlation with processing speed, working memory, attention/vigilance, and general cognitive ability, and positive correlation with intra-individual variability. 'Negative symptom factor' showed significant negative correlation only with general cognitive ability. Those two factors were also negatively correlated with function levels measured by Global Assessment Scale (GAS), and associated with poor treatment responses. CONCLUSION: Symptom-based dimensional phenotypes of schizophrenia measured on a lifetime basis showed discriminative correlation with cognitive function domains, global functioning level, and overall treatment responses, indicating their possibility as valid phenotype axes of schizophrenia having homogeneous biologic basis.
Appointments and Schedules ; Cognition ; Consensus ; Delusions ; Humans ; Memory, Short-Term ; Neuropsychological Tests ; Phenotype ; Schizophrenia*

Objectives: In this study, we conducted an exploratory analysis of the current media trends on schizophrenia using text-mining methods. Methods: First, web-crawling techniques extracted text data from 575 news articles in10 major newspapers between 2018 and 2019, which were selected by searching “schizophrenia” in the Naver News. We had developed document-term matrix (DTM) and/or term-document matrix (TDM) through pre-processing techniques. Through the use of DTM and TDM, frequency analysis, cooccurrence network analysis, and topic model analysis were conducted. Results: Frequency analysis showed that keywords such as “police,” “mental illness,” “admission,” “patient,” “crime,” “apartment,” “lethal weapon,” “treatment,” “Jinju,” and “residents” were frequently mentioned in news articles on schizophrenia. Within the article text, many of these keywords were highly correlated with the term “schizophrenia” and were also interconnected with each other in the co-occurrence network. The latent Dirichlet allocation model presented 10 topics comprising a combination of keywords: “police-Jinju,” “hospital-admission,” “research-finding,” “care-center,” “schizophrenia-symptom,” “society-issue,” “family-mind,” “woman-school,” and “disabled-facilities.” Conclusion The results of the present study highlight that in recent years, the media has been reporting violence in patients with schizophrenia, thereby raising an important issue of hospitalization and community management of patients with schizophrenia.

Objectives: This study aimed to investigate suicidal behaviors and the related psychopathology across the different stages of schizophrenia. Methods: We recruited 131 patients with schizophrenia and categorized them into two groups, according to the duration of illness (DI) as follows: ≤10 years (n=39) and >10 years (n=92). Psychopathology and suicidality were assessed using the 18-item Brief Psychiatric Rating Scale (BPRS-18) and the suicidality module from the Mini-International Neuropsychiatric Interview, respectively. Results: One-quarter of the patients with a DI ≤10 years and nearly one-sixth of the patients with a DI >10 years experienced suicidal behaviors in the previous month. Suicidality scores were significantly associated with the “affect” factor scores of the BPRS-18 in patients with a DI ≤10 years (β=0.55, p=0.003) and with the “resistance” factor scores in patients with a DI of >10 years (β=0.29, p=0.006). Conclusion The present study demonstrated that psychopathological factors were differentially associated with suicidality in patients with schizophrenia according to the illness stage. Our findings suggest that for effective suicide prevention, different approaches are required for the management of each stage of schizophrenia.

OBJECTIVES: Intra-individual variability of cognitive performance across different tests or domains has been reported as an important index of cognitive function. The aim of the current study is to examine the intra-individual variability across different cognitive domains and tests in patients with schizophrenia, their unaffected siblings, and normal controls. We also compared the variability among three patient sub-groups divided according to the duration of illness. METHODS: Comprehensive neurocognitive tests were administered in order to stabilize patients with schizophrenia (n=129), healthy siblings (n=38) of the patients, and normal controls (n=110). Intra-individual variability was computed from the variance of the scores of six cognitive domains of the Measurement and Treatment Research to Improve Cognition in Schizophrenia consensus battery. We examined intra-individual variability across six factor-based cognitive scores and individual test scores of each cognitive domain. RESULTS: Compared to the normal control and sibling groups, patients showed significantly increased intra-individual variability across six cognitive domains and individual cognitive tests of each domain. Compared to the normal control, siblings showed significantly increased intra-individual variability only across individual tests of the processing of speed domain. Among patient sub-groups, those with the longest duration of illness (> or =11 years) showed significantly higher intra- individual variability across six cognitive domains and across individual tests of the processing of speed domain compared to the other two groups. CONCLUSION: This study identified cognitive dissonances across six cognitive domain schizophrenia patients. These cognitive characteristics were not observed in the sibling groups and seemed to progress during the course of illness.
Cognition ; Cognitive Dissonance ; Consensus ; Humans ; Neuropsychological Tests* ; Schizophrenia* ; Siblings*

We present a case of 34-year-old female patient with major depressive disorder who had decreased metabolic activity of CYP2D6. Low dosage regimen of mirtazapine & paroxetine led to unexpectedly severe adverse effects and noncompliance in this case with genotype CYP2D6 *1/*5. Antidepressant change to imipramine with consideration of the genotyping resulted with tolerable adverse effects and remission of depression. This case suggests the clinical usefulness of pharmacogenetic testing in individualized antidepressant treatments.
Adult ; Cytochrome P-450 CYP2D6 ; Cytochrome P-450 Enzyme System* ; Cytochromes* ; Depression ; Depressive Disorder, Major* ; Female ; Genotype* ; Humans ; Imipramine ; Paroxetine ; Pharmacogenetics

This study aimed to investigate cognitive impairment and psychological distress of critically ill patients at discharge from intensive care unit (ICU). This study included 30 critically ill patients who had neither pre-existing dementia nor ongoing delirium. At ICU discharge, they performed a screening test for cognitive impairment (Mini-Cog test) and completed questionnaires for depression (Patient Health Questionnaire-2, PHQ-2) and for 4 stressful experiences during ICU stay including nightmares, severe anxiety or panic, severe pain, and trouble to breathe or feeling of suffocation (Post-Traumatic Stress Syndrome 14-Question Inventory, PTSS-14 Part A). Thirteen patients (43.3%) screened positive for cognitive impairment and 18 patients (60.0%) exhibited depressive symptoms. Twenty three patients (76.7%) recollected one or more stressful in-ICU experiences. Female patients (88.9%) was more likely to feel depressed at ICU discharge, compared to male patients (47.6%) (χ2=4.47, p=0.03). To the best of our knowledge, this is the first report on cognitive and psychological outcomes of ICU survivors in Korea. In this study, we observed that a considerable number of critically ill patients had experienced cognitive impairment or psychological distress at ICU discharge.
Anxiety ; Asphyxia ; Cognition Disorders* ; Critical Care* ; Critical Illness ; Delirium ; Dementia ; Depression ; Dreams ; Female ; Humans ; Intensive Care Units* ; Korea ; Male ; Mass Screening ; Panic ; Survivors

Objectives: ZZKetamine has been reported to have antidepressant effects or psychotomimetic effects. The aim of this study was to investigatethe behavioral effects of ketamine treatment at various sub-anesthetic doses in adolescent and adult naïve mice. Methods: ZZIn each experiment for adolescent and adult mice, a total of 60 male Institute of Cancer Research mice were randomly dividedinto 6 groups, which were intraperitoneally treated with physiological saline, 10, 20, 30, 40, and 50 mg/kg ketamine for consecutive3 days. At 1 day after last injection, the locomotor and depressive-like behaviors were evaluated in mice, using open field test (OFT)and forced swim test (FST), respectively. Results: ZZIn case of adolescent mice, ketamine dose was negatively correlated with total distance traveled in the OFT (Spearman’srho = -0.27, p = 0.039). In case of adult mice, we found significant positive correlation between ketamine dose and duration of immobilityin the FST (Spearman’s rho = 0.45, p < 0.001). Immobility time in the 50 mg/kg ketamine-treated mice was significantly higher comparedto the saline-treated mice (Dunnett’s post-hoc test, p = 0.012). Conclusions ZZWe found that the repeated treatment with ketamine could decrease the locomotor or prolong the duration of immobilityin mice as the dose of ketamine increased. Our findings suggest that sub-anesthetic doses of ketamine might induce schizophrenia-like negative symptoms but not antidepressant effects in naïve laboratory animals.

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.

Objective: This study aimed to investigate the changing seasonal pattern of suicides in Korea between 2000 and 2019. Methods: We calculated a seasonal pattern of suicides between 2000 and 2019 using a non-stationary cosinor model. In addition, we estimated the effect of each month on the suicide incidence compared to a reference month, using a generalized linear model with a categorical variable of the month. Then, we visualized the rate ratio curves of suicides by gender, age group, and subperiod. Results: We observed a seasonal pattern of suicides in Korea with a spring peak and a winter trough. The seasonal ups and downs were most pronounced in suicides among the elderly ≥65 years. However, the seasonal pattern has not been consistent over the past two decades, with lowering seasonal peaks since 2012. The amplitude of seasonality was also lower in 2010–2019 than in 2000–2009. Conclusion The seasonal pattern of suicides seems to have diminished in Korea in recent years. Thus, we need further studies to investigate climatic and non-climatic factors influencing the seasonality of suicides and the consequence of the change.

OBJECTIVE: In this study, we aimed to develop a model predicting individuals with suicide ideation within a general population using a machine learning algorithm. METHODS: Among 35,116 individuals aged over 19 years from the Korea National Health & Nutrition Examination Survey, we selected 11,628 individuals via random down-sampling. This included 5,814 suicide ideators and the same number of non-suicide ideators. We randomly assigned the subjects to a training set (n=10,466) and a test set (n=1,162). In the training set, a random forest model was trained with 15 features selected with recursive feature elimination via 10-fold cross validation. Subsequently, the fitted model was used to predict suicide ideators in the test set and among the total of 35,116 subjects. All analyses were conducted in R. RESULTS: The prediction model achieved a good performance [area under receiver operating characteristic curve (AUC)=0.85] in the test set and predicted suicide ideators among the total samples with an accuracy of 0.821, sensitivity of 0.836, and specificity of 0.807. CONCLUSION: This study shows the possibility that a machine learning approach can enable screening for suicide risk in the general population. Further work is warranted to increase the accuracy of prediction.
Forests ; Korea ; Machine Learning* ; Mass Screening ; ROC Curve ; Sensitivity and Specificity ; Suicide*