Exploring transfer effects on memory and its neural mechanisms through a computerized cognitive training in mild cognitive impairment: randomized controlled trial.

BACKGROUND: Computerized cognitive training (CCT) has been proposed as a potential therapy for cognitive decline. One of the benefits of CCT is a transfer effect, but its mechanism on the memory domain is unclear. This study aimed to investigate the transfer effect of non-memory multidomain CCT on the memory domain and its neural basis in patients with mild cognitive impairment (MCI) through a randomized controlled trial. METHODS: Patients with MCI recruited from memory clinics were randomly assigned to either the CCT or the control group. The CCT group received multidomain CCT training excluding memory training, while the control group read educational books with learning-based quizzes twice a week for 8 weeks. Participants underwent memory tests yielding a composite score, other cognitive domain tests, non-cognitive scales, and resting-state functional magnetic resonance imaging (rsfMRI), at baseline and after intervention. Within- and between-group comparisons, group × time interactions, and seed-to-voxel analyses in memory-involving brain networks were performed. RESULTS: The CCT group showed improvement over the control group in memory domain (Group × time, F = 5.87, P = 0.03, η2 = 0.31), which was related with the increased connectivity in the hippocampal-frontal and fusiform-occipital network. No other cognitive and non-cognitive symptoms differed between groups after adjusting for covariates. CONCLUSION: Eight weeks of multidomain CCT without memory training improved memory function and restored functional network in the hippocampal and medial temporal region in MCI patients. These results can provide evidence for the transferring ability of CCT on memory functioning with its neural basis.

The Difference in the Quality of Life of Korean Children With Attention-Deficit/Hyperactivity Disorder Between Before and After COVID-19.

Objectives: This study aimed to compare the quality of life (QoL) of children with attention-deficit/hyperactivity disorder (ADHD) before and during coronavirus disease-2019 (COVID-19) and to examine how their QoL is affected by emotional and environmental factors during COVID-19. Methods: Participants in the pre-COVID-19 (n=43) and COVID-19 (n=36) groups were recruited from the same university hospital. The Pediatric Quality of Life Inventory (PedsQL) 4.0 Child Self-report, the Children's Depression Inventory (CDI), the Revised Children's Manifest Anxiety Scale (RCMAS), the PedsQL 4.0 Parent Proxy Report, and the Conners' Parent Rating Scale (CPRS) were employed. Independent t-tests, Pearson's correlation analysis, and multiple regression analysis were conducted. Results: Caregivers assessed the children's QoL more negatively than the children themselves in both groups. Children with ADHD evaluated their physical function more negatively and anxiety was significantly higher in the COVID-19 group. In the COVID-19 group, the PedsQL child self-report was significantly predicted by the CPRS, the CDI, and environmental factors (i.e., relation to child and monthly household income). Conclusion: Children with ADHD in the COVID-19 group had a numerically lower QoL and significantly higher anxiety. To improve QoL, it is important to deal with not only depression but also ADHD symptoms and environmental factors.

The Effect of Bright Light Therapy on Sleep and Quality of Life in Patients With Poststroke Insomnia.

OBJECTIVE: Poststroke insomnia is common and negatively affects stroke recovery. The objective of this study was to determine the effectiveness of bright light therapy for mild-to-moderate stroke patients with insomnia. METHODS: This study was randomized, double blind, and placebo controlled. A 2-week trial was conducted on patients with mild-to-moderate stroke who had poststroke insomnia. Only patients who had experienced a first episode of stroke were enrolled in this study. Sleep parameters were measured using the Actiwatch Spectrum Pro for 7 days before and after light therapy. The instrument specifically collected data concerning sleep, mood state, fatigue, and subjective quality of life. Participants with poststroke insomnia received bright light therapy (10,000 lux) or placebo therapy for 30 minutes in the early morning. A total of 112 eligible participants entered the study, but only 56 patients were randomized to treatment (27 to bright light therapy and 29 to placebo therapy). RESULTS: Results from analysis of variance showed that the mean change of sleep latency (F(1,55) =4.793, p = .033) and sleep efficiency (F(1,55) = 5.625, p = .022) were significantly superior in bright light therapy over placebo. Bright light therapy resulted in significant improvements in daytime sleepiness, fatigue, mood, and quality of life in study participants (p < .05). CONCLUSIONS: Bright light therapy is a nonpharmacological treatment of early, poststroke insomnia in patients who had a mild to moderate stroke. In addition, bright light therapy is effective for the treatment of daytime sleepiness, fatigue, and depression and for improving quality of life in patients with poststroke insomnia. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04721574.

Effects of Virtual Reality-Based Cognitive Training in the Elderly with and without Mild Cognitive Impairment.

OBJECTIVE: This study aimed to introduce a 4-week long fully immersive virtual reality-based cognitive training (VRCT) program that could be applied for both a cognitively normal elderly population and patients with mild cognitive impairment (MCI). In addition, we attempted to investigate the neuropsychological effects of the VRCT program in each group. METHODS: A total of 56 participants, 31 in the MCI group and 25 in the cognitively normal elderly group, underwent eight sessions of VRCT for 4 weeks. In order to evaluate the effects of the VRCT, the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet was administered before and after the program. The program' s safety was assessed using a simulator sickness questionnaire (SSQ), and availability was assessed using the presence questionnaire. RESULTS: After the eighth session of the VRCT program, cognitive improvement was observed in the ability to learn new information, visuospatial constructional ability, and frontal lobe function in both groups. At the baseline evaluation, based on the SSQ, the MCI group complained of disorientation and nausea significantly more than the cognitively normal elderly group did. However, both groups showed a reduction in discomfort as the VRCT program progressed. CONCLUSION: We conclude that our VRCT program helps improve cognition in both the MCI group and cognitively normal elderly group. Therefore, the VRCT is expected to help improve cognitive function in elderly populations with and without MCI.

Significant Domains of Life Satisfaction That Affect Suicidal Behavior in Adolescents.

OBJECTIVES: Adolescent suicide is a serious national issue in Korea. Recently, life satisfaction has been recognized as a major factor related to this issue. The main purpose of this study was to identify the domains of life satisfaction that affect suicidal behavior in adolescence. METHODS: Data were collected from eight middle schools in Incheon, Korea. A total of 1297 students answered questions regarding their demographic characteristics, happiness, self-related life satisfaction domains (appearance, leisure time, physical health, and mental health), depressive symptoms, and suicidal behavior. RESULTS: In the Spearman correlation analysis, female sex, perceived socioeconomic status (SES), happiness, and all four self-related satisfaction scores showed significant correlations with depression and suicidality. Multivariate regression analysis suggested that suicidality was significantly affected by perceived SES, satisfaction with appearance, mental health satisfaction, and depression. Finally, depression was identified as a partial mediator of the association between mental health satisfaction and suicidality, and a complete mediator of the association between female sex and suicidality. CONCLUSION: Perceived SES, satisfaction with appearance, and mental health satisfaction significantly affected students' suicidality, with or without the effect of depression. Health authorities, educators, and family members must be aware of this to identify adolescents at suicide risk earlier.

Cognitive reserve and the effects of virtual reality-based cognitive training on elderly individuals with mild cognitive impairment and normal cognition.

BACKGROUND: Cognitive reserve (CR) is a concept proposed to account for discrepancies between the extent of brain pathology and clinical manifestations of that pathology. This study aimed to explore the associations between CR and the effects of cognitive training using fully immersive virtual reality (VR). METHODS: A total of 44 older adults (22 cognitively normal, 22 with mild cognitive impairment) underwent eight cognitive training sessions using VR for a period of 4 weeks. CR was assessed using the Cognitive Reserve Index questionnaire (CRIq). To evaluate baseline cognitive function and the effects of VR training, the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropsychological battery was administered to all participants before and after the training. RESULTS: Greater improvement in the total CERAD score was seen for cognitively normal participants with higher versus lower scores on the Education subdomain of the CRIq. Among patients with mild cognitive impairment, none of the CRIq subdomain scores (Education, Working Activity, Leisure Time) were related to a change in CERAD total scores. The CRIq total score did not predict the improvement of global cognition in either group. CONCLUSIONS: This study revealed different impacts of CR on cognitive training according to the participants' cognitive status. It also suggests that employing three proxies of CR rather than using a composite score would provide a more accurate understanding of one's CR.

A 9-Year Comparison of Dementia Prevalence in Korea: Results of NaSDEK 2008 and 2017.

BACKGROUND: In many high-income Western countries, the prevalence of dementia had been reduced over the past decades. OBJECTIVE: We investigated whether the prevalence of all-cause dementia, Alzheimer's disease, vascular dementia, and mild cognitive impairment (MCI) had changed in Korea from 2008 to 2017. METHODS: Nationwide Survey on Dementia Epidemiology of Korea (NaSDEK) in 2008 and 2017 was conducted on representative elderly populations that were randomly sampled across South Korea. Both surveys employed a two-stage design (screening and diagnostic phases) and diagnosed dementia and MCI according to the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders and the consensus criteria from the International Working Group, respectively. The numbers of participants aged 65 years or older in the screening and diagnostic phases were 6,141 and 1,673 in the NaSDEK 2008 and 2,972 and 474 in the NaSDEK 2017, respectively. RESULTS: The age- and sex-standardized prevalence of all-cause dementia and Alzheimer's disease showed nonsignificant decrease (12.3% to 9.8%, odds ratio [OR] = 0.89, 95% confidence interval [CI] = 0.54-1.48 for all-cause dementia; 7.6% to 6.8%, OR [95% CI] = 0.91 [0.58-1.42] for Alzheimer's disease). Vascular dementia decreased in the young-old population aged less than 75 years (2.7% to 0.001%, OR [95% CI] = 0.04 [0.01-0.15]) and in women (1.9% to 0.5%, OR [95% CI] = 0.27 [0.10-0.72]) while MCI remained stable (25.3% to 26.2%, OR [95% CI] = 1.08 [0.67-1.73]). CONCLUSION: We found that the prevalence of dementia in Korea showed a nonsignificant decrease between 2008 and 2017.

Variables Affecting Attitudes Toward Suicide Among the Adolescent Population.

Past research has supported the positive association between prosuicide attitudes and suicidal behavior. The aim of the present study was to determine the factor structure of adolescents' attitudes toward suicide and to explore correlates associated with their attitudes. A questionnaire was distributed to 1292 adolescents at eight middle schools to assess their demographic information, clinical variables, and attitudes toward suicide. After factor analysis, we reached a four-factor solution of the attitudes toward suicide. Significantly more females, nonreligious adolescents, those with a lower socioeconomic status, those with higher levels of depressive symptoms, and those with a history of suicidal ideation/plans had more understanding attitudes toward suicide. Depressive adolescents were also more permissive and believed that suicides were unpreventable and that loneliness led to suicide. In conclusion, adolescents' attitudes toward suicide were significantly associated with not only various sociodemographic correlates but also the severity of depressive symptoms and their own experiences of suicidality.

Association between Perceived Parenting Style and Adolescents' Attitudes toward Suicide.

OBJECTIVES: Adolescent suicide, a major cause of adolescent death, is affected by various factors, including attitudes toward suicide. This study investigated the association between parenting style and adolescents' attitudes toward suicide and the mediating role of attitude toward suicide between parenting style and suicidal ideation. METHODS: We surveyed 1,071 adolescents from eight middle schools in Incheon, Korea. The survey included sociodemographic information, attitudes toward suicide, perception of parenting style, depression severity, and suicidality. RESULTS: Students in the authoritarian parenting group had a more permissive attitude toward suicide compared with the democratic and permissive parenting groups. These students considered that suicide is justified in certain situations and that choosing suicide is an individual's right. They also had a negative attitude toward talking about suicide or intervening in others' suicide. This association remained statistically significant after adjusting for the impact of confounding factors that could affect attitudes toward suicide, except for suicidal processes and preparedness to prevent suicide. In the mediation analysis, we observed that some factors of the attitudes toward suicide mediated between authoritarian parenting attitudes and suicidal ideation, namely, suicide as a right, preventability, suicide as normal/common, preparedness to prevent suicide, and resignation. CONCLUSION: This study revealed the significant impact of parenting style on children's attitudes toward suicide. Educating parents about the appropriate parenting attitudes-sympathetic and rational-can help prevent youth suicide.

Relationship between subjective memory complaint and executive function in a community sample of South Korean elderly.

AIM: The aim of this study was to investigate the association between subjective memory complaint (SMC) and executive function in a community sample of South Korean elderly. METHOD: Data for 1442 non-cognitive impaired elderly individuals aged 65 and over were selected from a nationwide dementia epidemiological study conducted in South Korea. Global cognitive function was assessed by the Korean version of the Mini-Mental State Examination (MMSE-KC). The registration and recall subscales of the MMSE were used for evaluating memory function. Executive function was measured by using the Initiation/Perseveration (IP) subscale of the Korean dementia rating scale (K-DRS). RESULTS: Of the 1442 participants, 1088 were in the normal control group and 354 were in the SMC group. In the SMC group, compared to the normal control group, the proportion of depression was significantly higher, total MMSE scores, delayed recall score and total IP scores were significantly lower, and the mean scores of complex/simple verbal IP, alternating movements, and graphomotor design were lower. In the unadjusted linear regression model, the SMC significantly associated with a lower score of total MMSE-KC, MMSE delayed recall, K-DRS IP, complex/simple verbal IP, alternating movements and graphomotor design. After adjusting for age, gender, education, marital status, alcohol consumption, smoking behaviour, and depression, the SMC were significantly associated with lower total MMSE score, MMSE delayed recall, K-DRS IP, and K-DRS complex/simple verbal IP. CONCLUSION: In this population-based sample, individuals with SMC had evidence of lower performance on global cognition, memory function, and executive function, especially verbal fluency, after adjusting for demographic variables and depression.

Important Consideration in Choosing Antipsychotics in the Treatment of Patients with 22q11.2 Deletion Syndrome: Risk of Convulsion.

The prevalence of epilepsy and psychosis in 22q11.2 deletion syndrome (22q11.2DS) is higher than in the general population. Recent study on adults with 22q11.2DS reported that the most common trigger for provoked seizures was the use of antipsychotics and antidepressants. In this paper, blonaserin was used because aripiprazole, quetiapine, paliperidone were not effective. The patient had convulsion on the fourth day of taking blonaserin. Neurological and cardiac examination was carried out, and lamotrigine was added at the advice of neurologist. Than the patient didn't have any convulsions and the symptoms gradually improved. When treating patients with 22q11.2DS, the medicine should be chosen carefully, and the patient should be observed closely, paying attention to the possibility of convulsions.

Low-dose Quetiapine-induced Syndrome of Inappropriate Antidiuretic Hormone in a Patient with Traumatic Brain Syndrome.

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is characterized by hyponatremia, low serum osmolality, and clinical euvolemia in the absence of diuretic medication. And the causes of SIADH are various, antipsychotic agents and traumatic brain injury (TBI) are well known. Quetiapine is often chosen to manage the maladaptive behavior of patients with post-TBI. Although a previous study reported that quetiapine doses ranging from 25 to 300 mg were effective and tolerable, the symptoms of the patient might be aggravated. The symptoms of TBI such as nausea, malaise, headache, lethargy, and mild cognitive deficits are similar to those of SIADH. So the differentiation between SIADH and TBI may be difficult. This paper reports a case of SIADH in a patient with a TBI after using a small dose of 25 to 50 mg quetiapine.

Objective and subjective sleep problems and quality of life of rehabilitation in patients with mild to moderate stroke.

Objective: The principal objectives of this study were to investigate relationships between objective sleep parameters, that is, sleep onset latency, wake after sleep onset, number of awakenings, sleep efficiency, and sleep duration, and quality of life after mild to moderate stroke.Methods: The subjects were 112 first-time mild to moderate stroke patients admitted to a rehabilitation unit. Physical functions, depression, anxiety, quality of life, subjective insomnia, quality of sleep, and fatigue were assessed at about 20 days after stroke. Objective sleep parameters were also assessed using a wrist-worn Actiwatch.Results: Patients with insomnia had greater sleep onset latencies (p = .001), wake after sleep onset (p = .005), awoke more frequently (p = .013), and slept less efficiency (p < .001) than patients without insomnia, but total sleep durations were similar. In all participants, lower overall domain of quality of life was significantly associated with sleep onset latency (p = .009), and total insomnia severity index (p < .001), total Epworth Sleepiness Scale (p < .001), the National Institute's Health Stroke Scale (p = .004), the Modified Barthel Index (p = .034), and Screening Tests for Aphasia and Neurologic-Communication Disorders (p = .044) scores.Conclusion: Objective sleep parameters (sleep onset latency and sleep efficiency) were found to be associated with quality of life during the early stage of rehabilitation in mild to moderate stroke patients.

Perception of Stigma and Its Associated Factors Among Patients With Major Depressive Disorder: A Multicenter Survey From an Asian Population.

Stigma of major depressive disorder (MDD) is an important public health problem. This study aimed to examine the level of perceived stigma and its associated factors in MDD patients in five Asian countries, including China, Korea, Malaysia, Singapore, and Thailand. A total of 547 outpatients with MDD were included from Asian countries. We used the stigma scale of the Explanatory Model Interview Catalogue (EMIC) to assess stigma. The Montgomery-Asberg Depression Rating Scale (MADRS), Symptoms Checklist 90-Revised (SCL-90-R), Fatigue Severity Scale (FSS), Sheehan Disability Scale (SDS), 36-Item Short-Form Health Survey (SF-36), and Multidimensional Scale of Perceived Social Support (MSPSS) were used to assess symptoms, clinical features, functional impairment, health status, and social support. The stigma scores of patients under 55 years old were significantly higher than those equal to or greater than 55 years old (P < 0.001). The stigma scores exhibited significant negative correlation with age; MSPSS scores of family, friends, and others; and SF-36 subscale of mental health, but significant positive correlation with MADRS, FSS, SDS, and SCL-90-R subscale scores of depression, interpersonal sensitivity, obsession-compulsion, psychoticism, and somatization. Multivariate regression analysis revealed that age, SCL-90-R interpersonal sensitivity, obsession-compulsion, psychoticism, MSPSS scores of friends and others, and SF-36 of mental health were significantly associated with the level of perceived stigma. These findings suggest that MDD patients who are young, have a high degree of interpersonal sensitivity and psychoticism, have low health-related quality of life, and have low social support are the target population for stigma interventions in Asia.

The Influence of Depression and School Life on the Quality of Life of Korean Child and Adolescent Patients with Attention-Deficit/Hyperactivity Disorder:A Comparison of the Perspectives of the Patients and Their Caregivers.

OBJECTIVES: This study aimed to compare the quality of life reported by patients with attention-deficit/hyperactivity disorder (ADHD) to the patients' quality of life as reported by their caregivers. In addition, it aimed to examine how emotional problems, including depression and anxiety, and the severity of the symptoms affect the quality of life reported by the patients and their caregivers. METHODS: The patients' quality of life and their degree of depression and anxiety were measured using the Pediatric Quality of Life Inventory (PedsQL) 4.0 Child Self-Report, the Children's Depression Inventory (CDI), and the Revised Children's Manifest Anxiety Scale, respectively. The caregivers' perception of the patients' quality of life and severity of the ADHD symptoms were measured using the PedsQL 4.0 Parent Proxy Report and the Conners' Parent Rating Scale (CPRS), respectively. A total of 66 participants completed the survey. The independent-samples t-test, Pearson's correlation analysis, and multiple regression analysis were conducted. RESULTS: The mean score of the PedsQL 4.0 Child Self-Report was significantly higher than the mean score of the PedsQL 4.0 Parent Proxy Report. However, for school function, the PedsQL 4.0 Child Self-Report score was significantly lower than that of Parent Proxy Report. The correlation between the PedsQL 4.0 Child Self-Report and PedsQL 4.0 Parent Proxy Report scores was significant only for emotional function and social function. The multiple regression analysis showed that the PedsQL 4.0 Child Self-Report and PedsQL 4.0 Parent Proxy Report scores were significantly predicted by the CDI and CPRS scores, respectively. CONCLUSION: Our results demonstrate that there are clear differences between the quality of life reported by the patient themselves and that reported by their caregivers. In addition, the findings suggest that it is critical to treat the patients' accompanying depressive symptoms.

Prevalence and Risk Factors of Abusive Behaviors in the Caregivers of People with Dementia in Korea.

OBJECTIVE: We investigated the prevalence and risk factors of physically abusive behaviors (PhAB) and psychologically abusive behaviors (PsAB) towards people with dementia (PWD) in family caregivers, and compared their prevalences between East Asian and Western countries. METHODS: We estimated the prevalence and risk factors of PhAB and PsAB in 467 Korean pairs of community-dwelling PWD and their primary family caregivers. We evaluated abusive behaviors using the Modified Conflict Tactics Scale. In addition, we compared the prevalence of abusive behaviors between Asian and Western countries through a meta-analysis on 12 studies including the current one. RESULTS: More than a half of the caregivers reported PsAB and about one out of seven caregivers admitted PhAB within past three months. PsAB and PhAB were slightly more prevalent in East Asian countries than in Western countries. Non-Alzheimer type and moderate to severe behavioral and psychological symptoms of dementia were associated with the risk of PhAB but not with the risk of PsAB. Severe care burden and low income were associated with the risk of PhAB and PsAB. CONCLUSION: PhAB and PsAB were as prevalent in the family caregivers of PWD in Asian countries including Korea as in Western countries. Prevention strategies should be implemented according to the type of abusive behaviors.

Association of Body Mass Index with Suicide Behaviors, Perceived Stress, and Life Dissatisfaction in the Korean General Population.

OBJECTIVE: The purpose of the present study was to investigate the association between Body Mass Index, suicide, perceived stress, and life dissatisfaction in a general population sample of Korean adults. METHODS: A total of 6,022 nationally representative adults aged 18 to 74 were selected using a multistage cross-sectional cluster sampling method. Questionnaires regarding suicide behaviors, perceived stress, and life satisfaction were completed by the participants. They also reported their heights and weights, which were used to calculate BMI. Psychiatric disorders were diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, using the Korean version of the Composite International Diagnostic Interview. RESULTS: The results showed that being underweight was associated with higher risk for suicide ideation [odds ratio (OR), 1.6; 95% confidence interval (Cl), 1.18-2.05] and suicide attempt (OR, 2.0, 95% Cl, 1.23-3.31). Likewise, obesity also increased the risk of suicide ideation (OR, 1.3; 95% Cl, 1.11-1.56) although not suicide attempt. Furthermore, underweight individuals were more likely to report severe level of perceived stress (OR, 1.7; 95% Cl, 1.26-2.17) and life dissatisfaction (OR, 1.3; 95% Cl, 1.07-1.68). All of the results remained significant after adjusting for age, gender, education, and psychiatric illnesses. CONCLUSION: This study found that being underweight is a significant risk factor for suicide and poor subjective wellbeing in Korea. It suggests that BMI status may be an important modifiable factor for improving mental health in Korea.

Relationship between physicians' perceived stigma toward depression and physician referral to psycho-oncology services on an oncology/hematology ward.

OBJECTIVE: This study was performed to identify relationships between physicians' perceived stigma toward depression and psycho-oncology service utilization on an oncology/hematology ward. METHODS: The study participants were 235 patients in an oncology/hematology ward and 14 physicians undergoing an internal medicine residency training program in Inha University Hospital (Incheon, South Korea). Patients completed the Patient Health Questionnaire-9 (PHQ-9), and residents completed the Perceived Devaluation-Discrimination scale that evaluates perceived stigma toward depression. A total PHQ-9 score of ≥5 was defined as clinically significant depression. Physicians decided on referral on the basis of their opinions and those of their patients. The correlates of physicians' recommendation for referral to psycho-oncology services and real referrals psycho-oncology services were examined. RESULTS: Of the 235 patients, 143 had PHQ-9 determined depression, and of these 143 patients, 61 received psycho-oncology services. Physicians recommended that 87 patients consult psycho-oncology services. Multivariate analyses showed that lower physicians' perceived stigma regarding depression was significantly associated with physicians' recommendation for referral, and that real referral to psycho-oncology services was significantly associated with presence of a hematologic malignancy and lower physicians' perceived stigma toward depression. CONCLUSION: Physicians' perceived stigma toward depression was found to be associated with real referral to psycho-oncology services and with physician recommendation for referral to psycho-oncology services. Further investigations will be needed to examine how to reduce physicians' perceived stigma toward depression.

Prevalence and Psychiatric Comorbidities of Internet Addiction in a Nationwide Sample of Korean Adults.

The goal of the study was to examine the prevalence and psychiatric comorbidities of Internet addiction in a nationwide sample of Korean adults. Among a total of 6,022 participants involved in Korean Epidemiological Catchment Area study in 2011, 3,723 Internet users were assessed for their Internet addiction using Young's 8-item Diagnostic Questionnaire. The results showed that of the 3,723 Internet users, 39 (1.0%) had Internet addiction. Addicted Internet users were younger, more likely to be males and unemployed compared to non-addicted Internet users. Internet addiction was associated with alcohol and nicotine use disorders, depressive disorders, and anxiety disorder after controlling for age, gender, and occupational status. Internet addiction was associated with suicidal plans even after controlling for psychiatric disorders and socio-demographic factors. This study showed that Internet addiction is highly associated with variety of different psychiatric disorders and suicidal plans. Therefore, clinicians should carefully evaluate them when treating addicted Internet users.