Mood Disorder Severity and Subtype Classification Using Multimodal Deep Neural Network Models.

The subtype diagnosis and severity classification of mood disorder have been made through the judgment of verified assistance tools and psychiatrists. Recently, however, many studies have been conducted using biomarker data collected from subjects to assist in diagnosis, and most studies use heart rate variability (HRV) data collected to understand the balance of the autonomic nervous system on statistical analysis methods to perform classification through statistical analysis. In this research, three mood disorder severity or subtype classification algorithms are presented through multimodal analysis of data on the collected heart-related data variables and hidden features from the variables of time and frequency domain of HRV. Comparing the classification performance of the statistical analysis widely used in existing major depressive disorder (MDD), anxiety disorder (AD), and bipolar disorder (BD) classification studies and the multimodality deep neural network analysis newly proposed in this study, it was confirmed that the severity or subtype classification accuracy performance of each disease improved by 0.118, 0.231, and 0.125 on average. Through the study, it was confirmed that deep learning analysis of biomarker data such as HRV can be applied as a primary identification and diagnosis aid for mental diseases, and that it can help to objectively diagnose psychiatrists in that it can confirm not only the diagnosed disease but also the current mood status.

A Three-Year Longitudinal Study of Risk Factors for Suicidality in North Korean Defectors.

BACKGROUND: This longitudinal study examined risk factors for future suicidality among North Korean defectors (NKDs) living in South Korea. METHODS: The subjects were 300 NKDs registered with a regional adaptation center (the Hana Center) in South Korea. Face-to-face interviews were conducted using the North Korean version of the World Health Organization's Composite International Diagnostic Interview to diagnose mental disorders according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. Subjects were also asked about sociodemographic and clinical factors at baseline. At follow-up after three years, the NKDs (n = 172 respondents) were asked to participate in an online survey, responding to self-questionnaires about suicidality. Logistic regression analyses were used to explore associations between baseline variables and future suicidality among NKDs. RESULTS: Thirty (17.4%) of the 172 survey respondents reported suicidality at follow-up. The presence of health problems over the past year, any prior suicidality at baseline, a higher score on a trauma-related scale, and a lower score on a resilience scale at baseline were associated with greater odds of suicidality at follow-up after adjusting for age, sex, and educational level. Of all mental disorder categories, major depressive disorder, dysthymia, agoraphobia, and social phobia were also associated with significantly increased odds of suicidality at follow-up after adjusting for age, sex, educational level, and prior suicidality at baseline. CONCLUSION: Resilience, a previous history of suicidality, and the presence of lifetime depressive disorder and anxiety disorder should be given consideration in mental health support and suicide prevention in NKDs.

Comparative Metabolomic Analysis of Moromi Fermented Using Different Aspergillus oryzae Strains.

Aspergillus oryzae (A. oryzae) is an important starter in the fermentation of koji and moromi. However, the effect of different A. oryzae strains on the quality of moromi has rarely been studied. For this reason, this study analyzed the physicochemical properties, enzyme activity, sensory quality, and metabolite profiles of moromi samples fermented using two strains (A. oryzae KCCM12012P (moromi-1) and KCCM12804P (moromi-2)), which were newly isolated from fermented soy foods, and compared them to those of a commercialized A. oryzae strain (control). Amino-type nitrogen contents of moromi-1 and moromi-2 samples were higher than that of control moromi, and their amylase and protease activities were also higher. Moreover, metabolite profiles of moromi were significantly altered according to strains. In particular, the levels of many amino acids, peptides, nucleotides, and acidic compounds were altered, which resulted in changes in the sensory quality of moromi. Although volatile compounds were not investigated, the results suggested that the quality of moromi was significantly different for newly isolated strains, especially A. oryzae KCCM12804P, and they were superior to the commercial strain in terms of taste-related substances. Therefore, these strains could be used as good starters to produce moromi and soy sauce with good sensory quality.

Prevalence of intimate partner violence victimization and its association with mental disorders in the Korean general population.

This study assessed the association between experiencing physical or sexual intimate partner violence (IPV) and mental health among women in the general Korean population. A total of 3160 South Korean women aged 18 to 74 responded to the Korean version of the WHO-Composite International Diagnostic Interview (K-CIDI), version 2.1., and questions about IPV. Multiple logistic regression was used to examine the odds of developing mental disorders associated with each type of IPV. Victimization by any type of IPV was associated with significantly increased odds of experiencing any mental disorders in the lifetime (OR 4.4, 95% CI 2.4-8.0). Participants who experienced sexual IPV had the highest odds of having mental disorders (OR 14.3, 95% CI 4.1-54.8). Sexual IPV experience among participants was associated with higher odds of major depressive disorder, anxiety disorder, obsessive-compulsive disorder, post-traumatic stress disorder, generalized anxiety disorder, specific phobias, agoraphobia, and nicotine dependence. Alcohol use disorder was highly associated with experiencing physical IPV (OR 3.8, 95% CI 1.7-8.0). Among women who experienced IPV, the youngest age group, from 18 to 35 years old (2.6%, 95% CI 1.4-3.8), and the never married group (2.7%, 95% CI 1.2-4.2) experienced the highest proportion of any form of IPV. Mental disorders throughout the lifetime are highly associated with the experience of IPV among women and are most prevalent among those who experienced sexual IPV. Thus, to prevent mental disorders among female IPV victims, treatment specific to each type of IPV should be provided early.

An Ultrasensitive, Selective, Multiplexed Superbioelectronic Nose That Mimics the Human Sense of Smell.

Human sensory-mimicking systems, such as electronic brains, tongues, skin, and ears, have been promoted for use in improving social welfare. However, no significant achievements have been made in mimicking the human nose due to the complexity of olfactory sensory neurons. Combinational coding of human olfactory receptors (hORs) is essential for odorant discrimination in mixtures, and the development of hOR-combined multiplexed systems has progressed slowly. Here, we report the first demonstration of an artificial multiplexed superbioelectronic nose (MSB-nose) that mimics the human olfactory sensory system, leading to high-performance odorant discriminatory ability in mixtures. Specifically, portable MSB-noses were constructed using highly uniform graphene micropatterns (GMs) that were conjugated with two different hORs, which were employed as transducers in a liquid-ion gated field-effect transistor (FET). Field-induced signals from the MSB-nose were monitored and provided high sensitivity and selectivity toward target odorants (minimum detectable level: 0.1 fM). More importantly, the potential of the MSB-nose as a tool to encode hOR combinations was demonstrated using principal component analysis.

The Effect of Time Spent on Online Gaming on Problematic Game Use in Male: Moderating Effects of Loneliness, Living Alone, and Household Size.

OBJECTIVE: This study aimed to investigate the association between gaming time and problematic game use (PGU) within a large sample of Korean male gamers and to examine the potential moderating effects of loneliness, living alone, and household size. METHODS: This study employed data from 743 male gamers from the National Mental Health Survey 2021, a nationally representative survey of mental illness conducted in South Korea. Self-reported data on the average gaming time per day, severity of PGU, loneliness, living alone, and household size were used. RESULTS: Gaming time was positively associated with PGU and this relationship was significantly moderated by loneliness such that the positive effect of gaming time on PGU was greater when the levels of loneliness were high. The three-way interaction effect of gaming time, loneliness, and living alone was also significant, in that the moderating effect of loneliness on the relationship between gaming time and PGU was significant only in the living alone group. However, household size (i.e., number of housemates) did not moderate the interaction between gaming time and loneliness among gamers living with housemates. CONCLUSION: These results suggest the importance of considering loneliness and living arrangements of male gamers, in addition to gaming time, in identifying and intervening with individuals at heightened risk of PGU.

Higher metabolic variability increases the risk of depressive disorder in type 2 diabetes mellitus: a longitudinal nationwide cohort study.

Background and objectives: While variabilities in metabolic parameters (METv) have been linked to adverse health outcomes in type 2 DM, their association with depression is yet to be studied. This research aimed to investigate the association between METv and depressive disorder in patients with type 2 DM. Methods: The study involved a nationwide cohort of 1,119,631 type 2 DM patients who had undergone three or more serial health examinations between 2005 and 2012. At each visit, body mass index (BMI), fasting glucose (FG), systolic blood pressure (BP), and total cholesterol (TC) were measured and stratified into quartiles, with Q4 being the highest and Q1 the lowest. The risk of depressive disorder was evaluated using Cox proportional hazard regression models, which accounted for METs in the indexes, after adjusting for sex, income status, lifestyle habits, medical comorbidities, DM severity, and baseline levels of BMI, FG, BP, and TC. Results: During a mean follow-up period of 6.00 ± 2.42 years, 239,477 (21.4%) cases of type 2 DM patients developed depressive disorder. The risk of developing depressive disorder was gradually increased as the number of METv increased (HR 1.18; 95% CI 1.13, 1.23 for the group with the highest METv in all parameters compared to those with the lowest METv in all parameters). In the subgroup analysis, the risk of developing depressive disorder was 43% higher in men (HR 1.43; 95% CI 1.34, 1.51), and 31% higher in those younger than 65 years of age (HR 1.31; 95% CI 1.23, 1.39) in the group with the highest number of METv compared to the group with the lowest number of METv. Conclusion: In type 2 DM, higher METv was an independent risk factor for depressive disorder. This risk is notably elevated in men and individuals under the age of 65 years.

Association of physical activity with the risk of Parkinson's disease in depressive disorder: A nationwide longitudinal cohort study.

Regular physical activity (PA) has been suggested as effective disease preventable strategies for Parkinson's disease (PD). Depression often precedes PD but whether PA also would reduce the risk of PD in patients with depression has not been known. The aim of study is to examine the association of regular PA with risk of PD among patients with depressive disorder. A total of 1,342,282 patients with depressive disorder were identified from a nationwide health screening cohort from 2010 to 2016. The exposure was changes in pattern of regular PA between pre-and post-diagnosis of depressive disorder, categorized as four groups; 1) no PA, 2) increased PA, 3) decreased PA, and 4) maintaining PA. The outcome was risk of incident PD, calculated using multivariate adjusted Cox proportional hazards regressions according to the PA categorization. Total of 8901 PD cases (0.66%) were developed during 5.3 years of follow-up period. Maintaining PA group was associated with the lowest risk of PD (adjusted hazard ratio [aHR] 0.89, 95% CI 0.83-0.97) among all other PA groups with depressive disorder (with no PA group as reference). Otherwise, decreased PA group significantly increased the risk of PD (aHR 1.10, 95% CI 1.03-1.16). Those who maintained PA before and after diagnosis of depressive disorder were associated with lower risk of incident PD.

Rasch Analysis of the Korean Version of the Tinnitus Handicap Inventory.

Tinnitus is the perception of abnormal sounds in the ears or head without external auditory stimulation. While classical test theory is often used in tinnitus questionnaire development, it has limitations in assessing item characteristics. Item response theory (IRT) offers more precise individual ability estimations and identifies key and less important items, making it superior for reliable measurement tools. This study investigated the suitability of the Korean version of the Tinnitus Handicap Inventory (K-THI) as a patient-reported outcome measure (PROM) for clinical trials. Using Rasch analysis based on IRT, we evaluated K-THI's measurement of tinnitus-related disability in 545 patients (40.4% men, 59.6% women). Five items (2, 7, 8, 19, and 24) did not fit the Rasch model, yet a unidimensional scale and good fit for person and item data emerged (person: 0.89; item: 0.98). The three-point rating scale in K-THI proved suitable. IRT allowed precise evaluation of K-THI's properties, vital for reliable PROMs in patient-centered care. Our findings highlight IRT's role in questionnaire development, contributing to the advancement of PROMs.

Exploring trajectories of depressive symptoms in North Korean defectors: A latent class mixed analysis.

Background: North Korean defectors (NKDs) are known to be vulnerable to depression due to the influence of various psychosocial factors during their settlement process. Therefore, this study aimed to explore different trajectories of depressive symptoms in NKDs and identify predictors of the worsening of depressive symptoms. In particular, the focus was on whether posttraumatic stress disorder (PTSD) functions as a significant predictor. Methods: Participants consisted of 300 NKDs who settled in South Korea within 3 years of entering in the country. Five waves of longitudinal data collected from 2016 to 2019 were used. In this study, the North Korean Composite International Diagnostic Interview (NK-CIDI), a diagnostic interview tool, was conducted at baseline and depressive symptoms were measured at each wave. Trajectory identification was based on latent class mixed modeling. Logistic regression was used to extract the significant factors predicting a high/increasing depressive symptom trajectory. Results: Two trajectories of depressive symptoms were identified: "low/stable symptom" (76.7% of participants) and "high/increasing symptom" (23.3% of participants). Predictors of the high/increasing symptom group were being female and a low use of mental health services. Generalized anxiety disorder, social phobia, and alcohol dependence acted as significant predictors. Although PTSD was not a significant predictor, self-reported PTSD symptom scores were high in the high/increasing symptom group. Conclusions: Identifying the trajectories of depressive symptoms in NKDs helps identify the risk factors of clinically vulnerable groups. In the process of establishing government-level interventions, it may be helpful to create a therapeutic environment. In addition, when evaluating initial psychiatric problems, it is important to primarily consider NKDs' anxiety levels and alcohol problems. There should also be an appropriate consideration of PTSD symptoms.

Subthreshold lifetime depression and anxiety are associated with increased lifetime suicide attempts: A Korean nationwide study.

BACKGROUND: Subthreshold depression and anxiety are highly prevalent and known to be associated with functional limitations and future onset of major depression or anxiety disorders. However, studies regarding suicidality at subthreshold levels of depression and anxiety are limited. METHODS: A total of 17,639 Koreans aged from 18 to 64 responded to the Korean version of the WHO-composite international diagnostic interview (K-CIDI) version 2.1 between 2006 and 2016. Prevalence of subthreshold depression and anxiety, and information on lifetime suicide attempt (SA) were assessed. Multivariable logistic regression was performed to calculate the risk of SA by the level of depression or anxiety. RESULTS: The risk of lifetime SA increased incrementally according to the level of depression and anxiety. In the subthreshold depression group, individuals with subthreshold anxiety increased the odds about threefold (OR = 3.15, 95% CI 3.12-3.18) and the threshold anxiety disorder group increased the odds about fivefold (OR = 5.33, 95% CI 5.27-5.38) for SA, compared to the group without any level of anxiety. In threshold depressive disorder, the subthreshold anxiety group showed about 1.8-fold higher odds (OR = 1.76, 95% CI 1.75-1.77) and the threshold anxiety disorder group showed threefold higher odds (OR = 2.93, 95% CI 2.92-2.95) for SA compared to the group without any level of anxiety. CONCLUSIONS: Subthreshold levels of depression and anxiety were prevalent among Koreans and were associated with an increased prevalence of lifetime SA. A detailed assessment of depression and anxiety symptoms according to their level should be performed on a diagnostic continuum to prevent suicide.

Association between ankle brachial index and development of postoperative intensive care unit delirium in patients with peripheral arterial disease.

Patients with vascular diseases are prone to developing postoperative delirium (POD). Ankle brachial index (ABI) is a non-invasive clinical indicator of lower-extremities peripheral arterial disease (PAD) and has been identified as an indicator of cognitive impairment. We investigated the association between ABI and POD. 683 PAD patients who underwent elective leg arterial bypass surgery between October 1998 and August 2019 were collected for retrospective analysis. Demographic information, comorbidities, preoperative ABI and the Rutherford classification within one month prior to surgery were obtained. POD was assessed using the Confusion assessment method -intensive care unit. Logistic regression and receiver operating characteristics (ROC) curve analysis were used to assess the association between ABI and POD. The mean value of ABI was significantly lower in patients with POD than it was those without POD. Older age, more medical comorbidities, longer length of surgery, decreased ABI, and higher Rutherford class were all significantly associated with POD. The area under ROC (0.74) revealed that ABI below 0.35 was associated with development of POD. Lower preoperative ABI was associated with POD in PAD patients who underwent arterial bypass surgery.

Comparative Studies on Crystallinity, Thermal and Mechanical Properties of Polyketone Grown on Plasma Treated CVD Graphene.

In this work, we report a facile way to control crystalline structures of polyketone (PK) films by combining plasma surface treatment with chemical vapor deposition (CVD) technique. The crystalline structure of PKs grown on plasma-treated graphene and the resulting thermal and mechanical properties were systematically discussed. Every graphene sheet used in this work was produced by CVD method and the production of PKs having different crystallinity were performed on the O2- and N2-doped graphene sheets. It was evident that the CVD-grown graphene sheets acted as the nucleating agents for promoting the crystallization of ß-form PK, while suppressing the growth of α-form PK crystals. Regardless of the increase in surface roughness of graphene, surface functionality of the CVD-grown graphene was found to be an important factor in determining the crystalline structure of PK. N2 plasma treatment of the CVD-grown graphene promoted growth of the ß-form PK, whereas the O2 plasma treatment of CVD graphene led to transformation of the unoriented ß-form PK into the oriented α-form PK. Thus, the resulting thermal and mechanical properties of the PKs were highly dependent on the surface functionality of the CVD graphene. The method of controlling crystalline structure of the PKs suggested in this study, is expected to be very effective in realizing the PK with good processability, heat resistance and mechanical properties.

Social Isolation, Loneliness and Their Relationships with Mental Health Status in South Korea.

OBJECTIVE: This study aims to investigate the prevalence and psychological impact of social isolation and loneliness in South Korea. Loneliness and social isolation have been regarded as a risk to both physical and mental health. However, most studies have focused on the elderly; hence, there are limited studies on the characteristics of socially isolated or lonely people considering age. METHODS: A sample of 1,700 participants was selected from three major cities in South Korea. In-person interviews were conducted to evaluate loneliness, social isolation and mental health status. RESULTS: Among the participants, the prevalence of social isolation and loneliness was 17.8% and 4.1%, respectively. Males decreased the odds of loneliness (AOR 0.49, 95% CI=0.28-0.87), while increasing the odds of social isolation (AOR 1.44, 95% CI=1.12-1.86) after adjusting for age and sex. Greater depressive and social phobic symptoms were associated with increased odds of loneliness and social isolation. CONCLUSION: Social isolation and loneliness are prevalent among Koreans and associated with depression, social phobic symptoms, and suicidality. This study provides a foundation for further research to investigate nationwide prevalence and a more in-depth analysis of loneliness and social isolation.

High Bodyweight Variability Increases Depression Risk in Patients With Type 2 Diabetes Mellitus: A Nationwide Cohort Study in Korea.

Objectives: Although obesity is associated with increased risk for depression in patients with type 2 diabetes mellitus (DM), the relationship between body weight variability (BWV) and depression remains poorly studied. This study was to investigate the incidence of depression in patients with type 2 DM according to their BWV. Methods: Intraindividual variation in body weight were measured in the nationwide, population-based retrospective cohort of 540,293 patients with type 2 DM from the Korean national health insurance system between 2009 and 2010. The diagnoses of new-onset depression occurring until the end of 2017 were ascertained. Risk of new-onset depression was examined using multivariate-adjusted Cox proportional hazards regression analysis by BWV quartile. Results: 93,149 (17.2%) patients developed new-onset depression for the follow up. BWV was significantly associated with an increased risk of depression after adjusting for confounding factors. The highest BWV quartile group had a hazard ratio (HR) of 1.17 (95% CI 1.15-1.19) compared to the lowest BWV quartile group as a reference. Obese patients in the highest BWV quartile group showed 12% increased risk of depression (HR 1.12, 95% CI 1.09-1.15) while non-obese patients in the highest BWV quartile group showed 20% increased risk of depression (HR: 1.20, 95% CI: 1.17-1.23) compared to their respective lowest BWV quartile groups. Conclusion: A higher BWV was significantly associated with an increased risk of depression in patients with type 2 DM. Thus, BWV may serve as an indicator for early detection of depression in type 2 DM patients.

Peptide hormone sensors using human hormone receptor-carrying nanovesicles and graphene FETs.

Hormones within very low levels regulate and control the activity of specific cells and organs of the human body. Hormone imbalance can cause many diseases. Therefore, hormone detection tools have been developed, particularly over the last decade. Peptide hormones have a short half-life, so it is important to detect them within a short time. In this study, we report two types of peptide hormone sensors using human hormone receptor-carrying nanovesicles and graphene field-effect transistors (FETs). Parathyroid hormone (PTH) and glucagon (GCG) are peptide hormones present in human blood that act as ligands to G protein-coupled receptors (GPCRs). In this paper, the parathyroid hormone receptor (PTHR) and the glucagon receptor (GCGR) were expressed in human embryonic kidney-293 (HEK-293) cells, and were constructed as nanovesicles carrying the respective receptors. They were then immobilized onto graphene-based FETs. The two hormone sensors developed were able to detect each target hormone with high sensitivity (ca. 100 fM of PTH and 1 pM of GCG). Also, the sensors accurately recognized target hormones among different types of peptide hormones. In the development of hormone detection tools, this approach, using human hormone receptor-carrying nanovesicles and graphene FETs, offers the possibility of detecting very low concentrations of hormones in real-time.

Comparisons Between Successful Versus Unsuccessful Switches From Benzodiazepines or Zolpidem (Z-Drug) to Controlled-Release Melatonin in Patients With Major Depressive Disorder and Insomnia.

OBJECTIVES: Chronic use of benzodiazepines and zolpidem (BDZ/Z-drugs) leads to dependency, cognitive impairment, and falls. Although controlled-release melatonin (Melatonin CR) may be an alternative, a switch in clinical settings has proven difficult. We investigated the factors associated with successful switch to Melatonin CR in patients with major depressive disorder (MDD) and insomnia. METHODS: This retrospective observational study involved 170 patients diagnosed with MDD and insomnia, and aged older than 55 years, who were treated with BDZ/Z-drug for at least the past 90 days and never before exposed to Melatonin CR. All patients were treated with a standard antidepressant therapy and Melatonin CR for their insomnia. A successful switch was defined as three or more consecutive prescriptions of Melatonin CR separated by at least one-month interval, after discontinuation of the BDZ/Z-drug. RESULTS: Seventy-nine patients (46.5%) who switched successfully showed no significant differences in sex, age, education, and occupational status compared with the unsuccessful group. The types of antidepressants used or BDZ/Z-drug treatment did not differ significantly between the two groups. Fewer somatic symptoms were observed in the successful group. In the multivariate analysis, the successful group showed significantly less somatic anxiety, shorter duration from first BDZ/Z-drug use to the first antidepressant use, and shorter total duration of BDZ/Z-drug therapy. CONCLUSIONS: A successful switch from BDZ/Z-drug to Melatonin CR was associated with less baseline somatic anxiety, earlier use of antidepressants, and shorter total duration of BDZ/Z-drug use, but was less strongly associated with the type of antidepressants in MDD patients with insomnia.

Prevalence of DSM-IV Major Psychiatric Disorders among North Korean Defectors in South Korea.

OBJECTIVE: The aim of this study was to estimate the prevalence of major psychiatric disorders among North Korean defectors (NKD) settled in South Korea. METHODS: The study population consisted of 294 North Korean defectors, aged 18 to 64 years settled in South Korea for 3 years or less. Between June 1, 2016 and October 31, 2016, face-to-face interviews were conducted using the North Korean version of the WHO-Composite International Diagnostic Interview (NK-CIDI) to diagnose DSM-IV psychiatric disorders. RESULTS: The lifetime prevalence of any DSM-IV psychiatric disorders was 62.2% in NKD and 25.0% in the general Korean population. The prevalence of specific disorders in NKD and general Korean population was as follows: 22.3% and 4.9% for major depressive disorder (MDD), 12.2% and 1.4% for post-traumatic stress disorder (PTSD), 18.0% and 4.8% for nicotine dependence, and 14.5% and 11.2% for alcohol abuse. The incidence of every single psychiatric disorder varied in each country. For instance, the generalized anxiety disorder, specific phobia, and alcohol use disorder occurred more frequently in North Korea whereas PTSD was more prevalent in other countries. CONCLUSION: The prevalence of psychiatric disorders among NKD was quite higher than in the general population of South Korea.

Perceived Trajectories of Past, Present, and Future Life Satisfaction of North Korean Defectors.

This study compared perceived trajectories of life satisfaction (LS) between North Korean defectors' (NKDs') and the general South Korean population and examined psychosocial factors associated with future LS. Data were obtained from 300 NKDs residing in South Korea and 5089 South Koreans using self-questionnaires and face-to-face interviews. LS values from 5 years ago (3.46 vs. 6.18) and at present (5.30 vs. 5.91) were lower in NKDs than the control group, but the inverse was true for expected LS score in 5 years (7.82 vs. 6.87). NKDs' LS trajectory showed a more statistically positive trend than that of the control group. Among NKDs, subjective sense of loneliness and satisfaction with one's sense of autonomy were associated with expected future LS. NKDs experience higher life satisfaction and expect an optimistic future relative to the control group. Social policies and therapeutic approaches to loneliness and improving a sense of autonomy may be beneficial.

Risk of suicide and accidental deaths among elderly patients with cognitive impairment.

BACKGROUND: The leading causes of death among the elderly with cognitive impairment are unknown. This study aims to estimate the suicide and accidental death rates on the basis of a clinical case registry of patients diagnosed with cognitive impairment. METHODS: The target sample consisted of 10,169 patients diagnosed with dementia or mild cognitive impairment (MCI), who were evaluated at the Clinical Research Center for Dementia of Korea (CREDOS) from January 2005 to December 2013. Information about whether the patients had died from suicide or in any kind of accident by December 31, 2016, was obtained from the database of the National Statistical Office (NSO). The standardized mortality ratio (SMR) and Cox-regression analysis were performed for evaluating the risk of suicide and accidental death as identified by the ICD-10. RESULTS: The average of the Clinical Dementia Rating Scale (CDR) score (0.68 vs 0.93) was lower, and the age at the time of study registration (71.42 vs 75.68 years) was younger in the suicidal death group, as compared to the accidental death group. The overall SMR for accidental death in cognitively impaired patients (1.44, 95% CI 1.22-1.71) was significantly higher than the general population. Later onset (1.43, 95% CI 1.20-1.71) and older age (2.21, 95% CI 1.04-4.68) increased the risk of accidental death in cognitively impaired patients. According to the dementia subtypes, the SMR for accidental death was higher in both Alzheimer's disease (1.72, 95% CI 1.36-2.14) and vascular dementia (2.14, 95% CI 1.27-3.38). Additionally, the SMR for accidental death showed an increasing tendency as the CDR score increased (mild 1.80, 95% CI 1.32-2.42, moderate 1.86, 95% CI 1.07-3.03, severe 3.32, 95% CI 1.08-7.76). Unemployment increased the risks of both suicide (3.71, 95% CI 1.54-8.95) and accidental death (2.09, 95% CI 1.20-3.63). CONCLUSIONS: Among people with cognitive impairment, the risk of death by suicide did not increase, whereas that of accidental death increased significantly. Preventive strategies for premature mortality in those with cognitive impairment should be implemented from the early stages and should include careful evaluation of the individual risk factors for each type of death.