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.

Objectives: ZZThe aim was to find effective vectorization and classification models to predict a psychiatric diagnosis from text-basedmedical records. Methods: ZZElectronic medical records (n = 494) of present illness were collected retrospectively in inpatient admission notes withthree diagnoses of major depressive disorder, type 1 bipolar disorder, and schizophrenia. Data were split into 400 training data and 94 independentvalidation data. Data were vectorized by two different models such as term frequency-inverse document frequency (TF-IDF)and Doc2vec. Machine learning models for classification including stochastic gradient descent, logistic regression, support vectorclassification, and deep learning (DL) were applied to predict three psychiatric diagnoses. Five-fold cross-validation was used to find aneffective model. Metrics such as accuracy, precision, recall, and F1-score were measured for comparison between the models. Results: ZZFive-fold cross-validation in training data showed DL model with Doc2vec was the most effective model to predict the diagnosis(accuracy = 0.87, F1-score = 0.87). However, these metrics have been reduced in independent test data set with final workingDL models (accuracy = 0.79, F1-score = 0.79), while the model of logistic regression and support vector machine with Doc2vec showedslightly better performance (accuracy = 0.80, F1-score = 0.80) than the DL models with Doc2vec and others with TF-IDF. Conclusions ZZThe current results suggest that the vectorization may have more impact on the performance of classification thanthe machine learning model. However, data set had a number of limitations including small sample size, imbalance among the category,and its generalizability. With this regard, the need for research with multi-sites and large samples is suggested to improve the machinelearning models.

Objectives: ZZThe purpose of this study is to investigate the interest level, perception and attitude of suicide high-risk group towardthe media’s suicide report, and also to provide the fundamental data in order to strengthen both the standard and the recommendationof media coverage in Korea. Methods: ZZWe analyzed the data from the 2013 The Korea National Suicide Survey. The study included 1500 participants aged between19 and 75 years. The participants were selected through the regional multi-layer stratification method using the sampling frameof the 2010 Census. One-on-one face-to-face interviews investigated the interest level, opinions, and attitudes toward suicide reportsand collected data on past suicide history and demographic data. The collected data were evaluated using multiple logistic regressionanalysis. A probability level of p < 0.05 was considered statistically significant. Results: ZZThe suicide high risk groups with histories of suicidal ideations or attempts showed more interest in suicidal reports [suicidalthought odds ratio (OR) = 1.81, 95% confidence interval (CI) = 1.40–2.34 ; suicidal attempt OR = 3.21, 95% Cl = 1.52–6.78]. However,there was no difference among the groups in thought that suicide reports incite suicide (suicidal thought OR = 1.26, 95% Cl = 0.92–1.73 ; suicidal attempt OR = 0.96, 95% Cl = 0.44–2.09). The suicide high risk groups showed a positive attitude toward suicide reports,but it was not statistically significant (suicidal thought OR = 1.10, 95% Cl = 0.41–2.92 ; suicidal attempt OR = 1.10, 95% Cl = 0.76–1.59). Conclusions ZZWe suggest the need of careful attitude of media suicidal reports not to bring about copycat suicides. and also we offersuicide prevention campaign based on media leverage.

Objectives: ZZIn electroconvulsive therapy (ECT) research and practice, the precise determination of seizure duration is importantin the evaluation of clinical relevance of the ECT-induced seizure. In this study, we have developed computerized algorithms to assessthe duration of ECT-induced seizure. Methods: ZZSubjects included 5 males and 6 females, with the mean age of 33.1 years. Total 55 ECT sessions were included in theanalysis. We analyzed the standard deviation of a finite block of electroencephalography (EEG) data and the change in the local slope ofRR intervals in electrocardiography (ECG) signals during ECT-induced seizure. And then, we compared the calculated seizure durationsfrom EEG recording (EEG algorithm) and ECG recording (ECG algorithm) with values determined by consensus of clinicians basedon the recorded EEG (EEG consensus), as a gold standard criterion, in order to testify the computational validity of our algorithms. Results: ZZThe mean seizure durations calculated by each method were not significantly different in sessions with abrupt flattenedpostictal suppression and in sessions with non-abrupt flattened postictal suppression. The intraclass correlation coefficients (95% confidenceinterval) of the three methods (EEG algorithm, ECG algorithm, EEG consensus) were significant in the total sessions [0.79(0.70–0.86)], the abrupt flattened postictal suppression sessions [0.84 (0.74–0.91)], and the non-abrupt flattened postictal suppressionsessions [0.67 (0.45–0.84)]. Correlations between three methods were also statistically significant, regardless of abruptness of transition. Conclusions ZZOur proposed algorithms could reliably measure the duration of ECT-induced seizure, even in sessions with nonabrupttransitions to flat postictal suppression, in which it is typically difficult to determine the seizure duration.

Leucine rich glioma inactivated (LGI1) encephalitis is an uncommon neurological disorder rarely encountered in clinical practice.However, it is a potentially fatal autoimmune syndrome that can decrease the level of consciousness, possibly progressing to coma.Additionally, unless diagnosed and promptly treated, it can cause permanent cognitive impairment. Since LGI1 encephalitis can initially present with psychiatric symptoms, there can be delays in reaching a proper diagnosis. This report describes a case of a 47-yearold woman with LGI1 antibodies-associated limbic encephalitis who initially presented with psychosis. Her blood tests were normal and no MRI and EEG abnormalities were found. Cerebrospinal fluid analysis was negative for other possible infectious causes. Three months after admission, she was found to be LGI1 antibody positive. LGI1 encephalitis should be suspected in patients with symptoms such as memory loss, confusion, seizures, and psychiatric symptoms. Prompt diagnosis and treatment of LGI1 encephalitis are warranted because prognosis becomes worse when such actions are delayed.

Objectives: The aim of this study is to investigate the association between secondhand smoke (SHS) exposure and depressive symptoms among Korean adults. This study also explored the mediating role of self-rated health (SRH) and perceived usual stress (PUS) in the association between depressive symptoms, suicidal ideation and SHS exposure. Methods: Data from the Korea National Health and Nutrition Examination Surveys (KNHANES) in 2014 and 2016 was analyzed for 10539 participants aged 19 years or older. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated in the logistic regression analysis with adjustment for the potential confounding factors. We also adopted the mediation analysis method by Hayes and Preacher. Results: After adjusting for the potential confounding factors, SHS at home and at public places were associated with depressive symptoms and suicidal ideation among non-smokers. After adjusting for the potential confounding factors, SHS at home and at public places was associated with depressive symptoms and suicidal ideation among non-smokers. Meanwhile SHS at workplaces was associated with depressive symptoms among former smokers and with suicidal ideation among current smokers. There was an additive effect of SHS on depressive symptoms only among non-smokers. SRH mediated the association between SHS and depressive symptoms and suicidal ideation among non-smokers. We did not observe any significant mediating effect of SRH nor PUS on the association between SHS and depressive symptoms among former and current smokers. Conclusions SHS may be associated with depressive symptoms and suicidal ideation in Korean adults. Our study elucidated how SHS interacted with depressive symptoms among non-smokers through the mediation by SRH.

Objectives: Amyloid β positron emission tomography (Aβ PET) is widely used as a diagnostic tool in patients who have symptoms of cognitive impairment, however, this diagnostic examination is too expensive. Thus, predicting the positivity of Aβ PET before patients undergo the examination is essential. We aimed to analyze clinical predictors of patients who underwent Aβ PET retrospectively, and to develop a predicting model of Aβ PET positivity. Methods: 468 patients who underwent Aβ PET with cognitive impairment were recruited and their clinical indicators were analyzed retrospectively. We specified the primary outcome as Aβ PET positivity, and included variables such as age, sex, body mass index, diastolic blood pressure, systolic blood pressure, education, dementia family history, Mini Mental Status Examination (MMSE), Clinical Dementia Rating (CDR), Clinical Dementia Rating-Sum of Box (CDR-SB), hypertension (HTN), diabetes mellitus (DM) and presence of apolipoprotein E (ApoE) E4 as potential predictors. We developed three final models of amyloid positivity prediction for total subjects, mild cognitive impairment (MCI) and Alzheimer’s disease (AD) dementia using a multivariate stepwise logistic regression analysis. Receiver operating characteristic (ROC) curve analysis was performed and the area under curve (AUC) value was calculated for the ROC curve. Results: Aβ PET negative patients were 49.6% (n = 232), and Aβ PET positive patients were 50.4% (n = 236). In the final model of all subjects, older age, female sex, presence of ApoE E4 and lower MMSE are associated with Aβ PET positivity. The AUC value was 0.296.In the final model of MCI subjects (n = 244), older age and presence of ApoE E4 are associated with Aβ PET positivity. The AUC value was 0.725. In the final model of AD subjects (n = 173), lower MMSE scores, the presence of ApoE E4 and history of HTN are associated with Aβ PET positivity. The AUC value was 0.681. Conclusions The cerebral amyloid positivity model, which was based on commonly available clinical indicators, can be useful for prediction of amyloid PET positivity in MCI or AD patients.Using Clinical Indicators

Objectives: The purpose of the present study was to examine the relationship between the chronotype and the burnout, so we investigated the mediating effects of the mediators such as perceived stress, stress response, and depression. Methods: Employees working at Incheon Customs conducted a mental health self-examination through the internet. Among them, 174 people who agreed to the mental health survey participated in the study. Participants completed questionnaires including Composite Scale of Morningness (CSM), Center for Epidemiological Studies-Depression Scale (CES-D), Perceived Stress Scale (PSS), Stress Response Inventory (SRI), Maslach Burnout Inventory-General Survey (MBI-GS). Results: Our results showed a higher degree of CES-D, SRI, exhaustion, and cynicism in evening and intermediate type compared to morning type, and a higher degree of professional efficacy in morning type compared to intermediate type. CSM was shown to have a direct effect on exhaustion and indirect effect through CES-D and SRI. CSM also had a direct effect on professional efficacy and had an indirect effect through the CES-D. However, CSM was found to have only indirect effects through the SRI for Cynicism. Conclusions In this study, individuals with evening type tend to experience a high degree of burnout (exhaustion, cynicism and professional efficacy) through the mediation effect of depression and stress response. Further study is necessary to reveal the effect of management of the depression and stress response in the employee with evening type.

Objectives: Psychological resilience plays a significant role in many aspects of mental health. The aim of this study was to find an association between childhood attention deficit hyperactivity disorder (ADHD) features and adulthood psychological resilience in patients with mood disorders. Methods: A total of 213 patients with mood disorders including major depressive disorder or bipolar I, II disorder and 909 healthy controls were included. We assessed childhood ADHD features using the Wender Utah Rating Scale (WURS), adulthood psychological resilience using the Connor-Davidson Resilience Scale (CD-RISC), and current depressive mood using the Beck Depression Inventory (BDI). Pearson’s correlation, multiple linear regression and a mediation analyses were performed to examine the relationships between three WURS factor (impulsivity, inattention, and mood instability) scores, the BDI score, and the CD-RISC score. Results: The CD-RISC score was negatively correlated with the WURS childhood inattention factor score and current BDI score in patients with mood disorders. BDI score mediated the influence of the inattention factor score on CD-RISC score among patients with mood disorders. The CD-RISC score was significantly lower in patients with mood disorders than in controls even after controlling for age, WURS scores, and the BDI score. Conclusions An evaluation of psychological resilience is important for enhancing recovery and quality of life in patients with mood disorders. When assessing psychological resilience, current depression and ADHD features in childhood, particularly inattention, should be considered.

Suicidality is the most serious complication of mood disorders and psychosis; effective treatment should reduce suicide rates. The Organization for Economic Cooperation and Development age-standardized suicide rate in Korea was 22.6 in 2018, much higher compared to other countries worldwide. As mental and psychiatric problems are the main reasons for suicide attempts, accounting for 31.6% in 2018, targeting such problems should be the focus of efforts to reduce suicide rates. However, the ability of current pharmacotherapeutic and psychotherapeutic interventions to reduce suicide rates is limited due to their delayed effects. Therefore, electroconvulsive therapy (ECT) has been proposed as an alternative treatment. This approach is effective for treating most mental disorders associated with high suicide rates, including severe depression, bipolar disorder, and intractable psychotic disorders; ECT is also effective for Parkinson’s disease, which has the highest suicide rate among all disorders in Korea. The acute, long-term, and prophylactic effects of ECT on suicidality have been reported in the literature, and treatment guidelines outside of Korea recommend that ECT be used at an early stage for rapid reduction of suicide rates, as opposed to being applied as a treatment of last resort. However, only ~0.092 of every 10000 members of the Korean general population received ECT in 2018; this is much lower than the average rate worldwide, of 2.2 per 10000. Elimination of obstacles to the use of ECT, early crisis intervention involving administration of ECT for rapid stabilization, and maintenance ECT to prevent recurrence should reduce suicide rates.