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Detection of Suicide Attempters among Suicide Ideators Using Machine Learning
Seunghyong Ryu,Hyeongrae Lee,Dong-Kyun Lee,Sung-Wan Kim,Chul-Eung Kim 대한신경정신의학회 2019 PSYCHIATRY INVESTIGATION Vol.16 No.8
Objective We aimed to develop predictive models to identify suicide attempters among individuals with suicide ideation using a machine learning algorithm. Methods Among 35,116 individuals aged over 19 years from the Korea National Health & Nutrition Examination Survey, we selected 5,773 subjects who reported experiencing suicide ideation and had answered a survey question about suicide attempts. Then, we performed resampling with the Synthetic Minority Over-sampling TEchnique (SMOTE) to obtain data corresponding to 1,324 suicide attempters and 1,330 non-suicide attempters. We randomly assigned the samples to a training set (n=1,858) and a test set (n=796). In the training set, random forest models were trained with features selected through recursive feature elimination with 10-fold cross validation. Subsequently, the fitted model was used to predict suicide attempters in the test set. Results In the test set, the prediction model achieved very good performance [area under receiver operating characteristic curve (AUC)=0.947] with an accuracy of 88.9%. Conclusion Our results suggest that a machine learning approach can enable the prediction of individuals at high risk of suicide through the integrated analysis of various suicide risk factors.
Seunghyong Ryu,Hee Jung Nam,Jae-Min Kim,Sung-Wan Kim 대한신경정신의학회 2021 PSYCHIATRY INVESTIGATION Vol.18 No.8
Objective This study aimed to investigate trends in hospital utilization of patients with schizophrenia during the last 10 years in Korea and to predict future trends using time series analysis. Methods We determined the numbers of patients receiving outpatient or inpatient treatment for schizophrenia per month between 2010 and 2019, using National Health Insurance claims data. Facebook’s Prophet was used to fit time series models based on observations for the previous 120 months, and to predict trends over the next 36 months. Results The number of hospitalized patients per month has declined rapidly since 2015, but the monthly number of outpatient visits has steadily increased. Monthly hospital utilization has increased in patients aged ≤29 and ≥50 years, but has declined rapidly since 2014-2015 in patients in their 30s and 40s. The upward trend in overall hospital utilization has slowed considerably in recent years. These trends are expected to continue over the next few years. Conclusion This study revealed some notable changes in the hospital utilization patterns of patients with schizophrenia in recent years. There is a need to closely monitor and anticipate potential problems caused by these changing trends.
Seunghyong Ryu,Hyeongrae Lee,Dong-Kyun Lee,Hee Jung Nam,Young-Chul Chung,Sung-Wan Kim 대한정신약물학회 2020 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.18 No.4
Objective: This study used network analyses to examine network structures reflecting interactions between specific domains of social functioning in schizophrenia (SZ) and bipolar disorder (BD). Methods: We used the World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) to assess six domains of social functioning (‘cognition’, ‘mobility’, ‘self-care’, ‘getting along’, ‘life activities’, and ‘participation’) in 143 patients with SZ, 81 patients with BD, and 106 healthy subjects. We constructed regularized partial correlation networks, estimated network centrality and edge strength, tested network stability, and compared SZ and BD network structures. Results: Patients with SZ showed a significantly higher level of functional disability than patients with BD. In the networks we constructed, ‘cognition’ was the most central domain of social functioning in both SZ and BD. The ‘cognition’ domain was primarily associated with the ‘getting along’ domain in the SZ network and the ‘life activities’ domain in the BD network. We found no significant group-level differences in network structures for SZ vs. BD. Conclusion: Our results suggest that cognition may play a pivotal role in social functioning in both SZ and BD. In addition, domains of social functioning in SZ and BD have similar network structures despite the higher level of disability in SZ compared to BD.
Decline in Hospital Visits by Patients with Schizophrenia Early in the COVID-19 Outbreak in Korea
Seunghyong Ryu,Hee Jung Nam,Seon-Hwa Baek,Min Jhon,Jae-Min Kim,Sung-Wan Kim 대한정신약물학회 2022 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.20 No.1
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.
Ryu, Seunghyong,Yoo, Jae Hyun,Kim, Joo Hyun,Choi, Ji Sun,Baek, Ji Hyun,Ha, Kyooseob,Kwon, Jun Soo,Hong, Kyung Sue by Lippincott Williams Wilkins. 2015 JOURNAL OF CLINICAL PSYCHOPHARMACOLOGY Vol.35 No.1
ABSTRACT: 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.
Lee, Seung-Tae,Ryu, Seunghyong,Nam, Hee Jung,Lee, Soo-Youn,Hong, Kyung Sue Ovid Technologies (Wolters Kluwer) - Lippincott Wi 2009 International clinical psychopharmacology Vol.24 No.3
<P>There is a wide interethnic variance in the pharmacokinetic profile of clozapine (CLZ), but the accumulated data are limited to some regional populations. In this study, we investigated the pharmacokinetic profile of CLZ in Korean patients and examined the association between serum CLZ parameters and clinical outcome. We assessed 78 Korean patients with schizophrenia who had been taking CLZ medication for more than 6 months. The patients were classified into three groups (good, moderate, and poor responders) according to their Clinical Global Impressions-Improvement scores. The serum concentrations of CLZ and norclozapine were 610.7+/-368.4 and 314.5+/-163.0 ng/ml (mean+/-SD), respectively, showing a large interindividual variation that was affected by dose, age, smoking habits, and sex by variable degrees. The pharmacokinetic profiles of Koreans were similar to those observed in Asians but quite different from those in Caucasians. Investigation on clinical responses revealed that the good or moderate responders clinically improved at a relatively low serum CLZ levels, whereas the poor responders showed less improvement despite the higher doses and serum levels. The metabolic ratio of the good responders was 0.65+/-0.20, higher than the poor responders (P=0.033). In this study, we identified a pharmacokinetic profile of CLZ in Korean schizophrenia patients and found a wide interindividual difference affected by various factors.</P>
Delay 정보를 이용한 LTE 기지국의 Power Saving 메커니즘
이승환(Seunghwan Lee),이승형(Seunghyong Rhee),최용훈(Yonghoon Choi),박수원(Suwon Park) 한국정보과학회 2010 정보과학회논문지 : 정보통신 Vol.37 No.3
시스템에서 UE의 QoS를 보장하면서 효율적인 power saving을 위해 본 논문에서는 delay 정보를 이용하여 3GPP(Third Generation Partnership Project) 규격에서 제시한 DRX/DTX(Discontinuous. Reception/Transmission)의 차등적 적용 MAC 프로토콜을 제안한다. 제안한 MAC 프로토콜은 LTE 기지국에서 각 UE의 QoS를 고려하여 적응적으로 DRX/DTX 주기를 제어한다. UE의 패킷 delay가 적은 경우에 DRX/DTX 주기를 늘려 에너지를 절약하고 패킷 delay가 커지면 기지국의 DRX/DTX 주기를 줄여 delay를 줄이고 UE의 QoS를 보장한다. DRX/DTX의 차등적용에 따른 모의실험 결과 제안된 power saving 방식은 DRX/DTX를 상황에 따라 변화시키지 않는 방식에 비해 개선된 power saving 성능을 제공하며 특히 상황에 맞게 DRX/DTX를 설정하여 UE의 요구사항을 충족시킬 수 있다. 본 논문에서는 LTE 기지국과 UE가 통신하는 환경에서 기지국의 에너지를 절약할 수 있는 MAC protocol을 제안하고 시뮬레이션을 통하여 성능이 향상되었음을 확인한다. This thesis proposes a power saving MAC protocol for LTE base station which utilizes different graded DRX/DTX(Discontinuous. Reception/Transmission) that specified by 3GPP(Third Generation Partnership Project). Considering QoS in UE, proposed MAC protocol controls adaptive DRX/DTX cycle. When Packet delay of UE is less than normal time, LTE base station economize power by increasing DRX/DTX. When Packet delay of UE is more than normal time, delay of UE is decreased by guaranteed QoS. It depends on the traffic which is sent by UE. The proposed method is more improve power saving performance than another method which is unchanged DRX/DTX by conditions. Especially when set DRX/DTX up in conditions, it will meet the requirements of UE. In this thesis, I propose an power saving MAC protocol in an environment where LTE base station are communicated with UE and prove improvement in performance through simulations.
Lee, Seung-Tae,Ryu, Seunghyong,Kim, Suk-Ran,Kim, Min-Ji,Kim, Seonwoo,Kim, Jong-Won,Lee, Soo-Youn,Hong, Kyung Sue Lippincott Williams Wilkins, Inc. 2012 JOURNAL OF CLINICAL PSYCHOPHARMACOLOGY Vol.32 No.4
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.
Cho, Youngah,Ryu, Seunghyong,Huh, Iksoo,Cho, Eun Young,Oh, Hyeji,Lee, Yu-Sang,Lee, Woo Kyeong,Park, Taesung,Kwon, Jun Soo,Hong, Kyung Sue RAPID COMMUNICATIONS OF OXFORD LTD 2015 PSYCHIATRIC GENETICS Vol.25 No.4
BACKGROUND: The neuregulin 1 (NRG1) gene has been investigated as a candidate susceptibility gene for schizophrenia. A number of studies have also explored the genetic effect of NRG1 on cognitive deficits related to schizophrenia, and thus far generated inconsistent results. The current study aimed to determine whether genetic variations in NRG1 are associated with cognitive domains in schizophrenic patients and healthy individuals. MATERIALS AND METHODS: Comprehensive neuropsychological tests composed of six cognitive domains were administered to 135 clinically stable patients with schizophrenia and 119 healthy individuals. On the basis of previous reports of positive association, a total of four single nucleotide polymorphisms were analyzed. In testing the genotype effect on cognitive domains, we used repeated-measure analysis for six cognitive domain scores of each individual as repeated measurements. RESULTS: An association of P-value less than 0.05 with at least one cognitive domain in patients and/or healthy individuals was observed for all of the single nucleotide polymorphisms. After applying the correction for multiple testing, the association remained statistically significant between rs6994992 and general cognitive ability (g) in the patient group and between rs2439272 and the ‘working memory’ domain in the group of healthy participants. CONCLUSION: This study suggests the involvement of NRG1 in the susceptibility for developing cognitive deficits in schizophrenic patients. For some cognitive domains, its genetic effect was also significant in generating interindividual variability within the normal functional range.