Validation of the Patient Health Questionnaire-9 and Patient Health Questionnaire-2 in the General Korean Population.

OBJECTIVE: The Patient Health Questionnaire-9 (PHQ-9) and PHQ-2 have not been validated in the general Korean population. This study aimed to validate and identify the optimal cutoff scores of the PHQ-9 and PHQ-2 in screening for major depression in the general Korean population. METHODS: We used data from 6,022 participants of the Korean Epidemiological Catchment Area Study for Psychiatric Disorders in 2011. Major depression was diagnosed according to the Korean Composite International Diagnostic Interview. Validity, reliability, and receiver operating characteristic curve analyses were performed using the results of the PHQ-9 and Euro Quality of life-5 dimension (EQ-5d). RESULTS: Of the 6,022 participants, 150 were diagnosed with major depression (2.5%). Both PHQ-9 and PHQ-2 demonstrated relatively high reliability and their scores were highly correlated with the "anxiety/depression" score of the EQ-5d. The optimal cutoff score of the PHQ-9 was 5, with a sensitivity of 89.9%, specificity of 84.1%, positive predictive value (PPV) of 12.6%, negative predictive value (NPV) of 99.7%, positive likelihood ratio (LR+) of 5.6, and negative likelihood ratio (LR-) of 0.12. The optimal cutoff score of the PHQ-2 was 2, with a sensitivity of 85.3%, specificity of 83.2%, PPV of 11.6%, NPV of 99.5%, LR+ of 5.1, and LR- of 0.18. CONCLUSION: The PHQ-9 and PHQ-2 are valid tools for screening major depression in the general Korean population, with suggested cutoff values of 5 and 2 points, respectively.

Prevalence of Loneliness and Its Association With Suicidality in the General Population: Results From a Nationwide Survey in Korea.

BACKGROUND: Although it is known that a substantial proportion of the population experience loneliness, the consequence of loneliness remains unclear by countries and ages. Accordingly, this study aimed to assess the association between loneliness and suicidality in the general population of Korea. METHOD: A total of 5,511 Koreans aged 18-79 completed a tablet-assisted personal interview using the Korean version of the Composite International Diagnostic Interview and responded to questions about loneliness and lifetime suicidal ideation, plans, and attempts. A logistic regression analysis was used to examine the association between loneliness and suicidality. RESULTS: Approximately one-third of the Korean general population reported loneliness. Being older, never married, widowed, separated, or divorced, unemployed, and having a part-time job were all significantly related to loneliness. After adjusting for sociodemographic factors, individuals with loneliness were significantly associated with increased suicidal ideation (adjusted odd ratio [aOR], 4.05; 95% confidence interval [CI], 3.36-4.88), suicidal plans (aOR, 4.91; 95% CI, 3.34-7.21), and suicidal attempts (aOR, 4.82; 95% CI, 3.03-7.66). Even after adjusting for sociodemographic factors and mental disorders, suicidality remained statistically significant. Moreover, frequent, moderate-to-severe, and long-term loneliness were all associated with increased ORs for suicidality, regardless of sociodemographic factors and mental disorders. CONCLUSION: Loneliness was associated with suicidal ideation, plans, and attempts. This study lays the foundation for public health policymakers to establish early intervention and mental health care support for lonely people.

Comparative Analysis on the Policy Approaches in the National Dementia Plans of G7 Countries and Korea and Their Implementation.

BACKGROUND: The World Health Organization (WHO) proposed a global action plan for dementia and aimed to have 75% of their member states formulating National Dementia Plans (NDPs) by 2025. The Organization for Economic Cooperation and Development (OECD) proposed the ten key objectives of dementia policy in 2015. Among previous studies on NDPs, few studies have investigated measures for proper implementation of NDPs. This study aimed to compare the implementation basis and specific action plans of NDPs between the G7 countries and South Korea. METHODS: We investigated the measures for proper implementation of the NDPs of G7 countries and South Korea. To compare the specific policy approaches, the seven action areas of the WHO action plan and the ten key objectives of dementia policy proposed by the OECD were integrated into 11 targets (prevention, diagnosis, awareness, caregiver support, appropriate environments, long-term care, health service, end-of-life care, care coordination, research and technology, information systems). RESULTS: Although most NDPs included specific action plans of the 11 targets, caregiver support, safe environments, healthcare services, and end-of-life care were lacking in some NDPs. For implementation, some countries reinforced the policy priority of their NDPs by timely updates, evaluation, legislations, or head-of-state leadership. However, only three countries had a legislative basis, and three countries included outcome measures in their latest NDP. CONCLUSION: Effective measures for feasible implementation are needed. The WHO should promote not only the establishment of NDPs, but also their proper implementation.

Prevalence of Mental Disorders and Associated Factors in Korean Adults: National Mental Health Survey of Korea 2021.

OBJECTIVE: Mental health is a global concern and needs to be studied more closely. We aimed to estimate the prevalence of mental disorders and their associated factors among the general population in Korea. METHODS: The National Mental Health Survey of Korea 2021 was conducted between June 19 and August 31, 2021 and included 13,530 households; 5,511 participants completed the interview (response rate: 40.7%). The lifetime and 12-month diagnosis rates of mental disorders were made using the Korean version of the Composite International Diagnostic Interview 2.1. Factors associated with alcohol use disorder (AUD), nicotine use disorder, depressive disorder, and anxiety disorder were analyzed, and mental health service utilization rates were estimated. RESULTS: The lifetime prevalence of mental disorders was 27.8%. The 12-month prevalence rates of alcohol use, nicotine use, depressive, and anxiety disorders were 2.6%, 2.7%, 1.7%, and 3.1%, respectively. The risk factors associated with 12-month diagnosis rates were as follows: AUD: sex and age; nicotine use disorder: sex; depressive disorder: marital status and job status; anxiety disorder: sex, marital status, and job status. The 12-month treatment and service utilization rates for 12-month AUD, nicotine use disorder, depressive disorder, and anxiety disorder were 2.6%, 1.1%, 28.2%, and 9.1%, respectively. CONCLUSION: Approximately 25% of adults in the general population were diagnosed with mental disorders during their lifetime. The treatment rates were substantially low. Future studies on this topic and efforts to increase the mental health treatment rate at a national level are needed.

National Dementia Plans of Group of Seven Countries and South Korea Based on International Recommendations.

This quality improvement study investigates whether national dementia plans in Group of Seven (G7) countries and South Korea conform to the recommendations of the World Health Organization and the Organization for Economic Cooperation and Development.

Clinical Approaches to Late-Onset Psychosis.

Psychosis can include schizophrenia, mood disorders with psychotic features, delusional disorder, active delirium, and neurodegenerative disorders accompanied by various psychotic symptoms. Late-onset psychosis requires careful intervention due to the greater associated risks of secondary psychosis; higher morbidity and mortality rates than early-onset psychosis; and complicated treatment considerations due to the higher incidence of adverse effects, even with the black box warning against antipsychotics. Pharmacological treatment, including antipsychotics, should be carefully initiated with the lowest dosage for short-term efficacy and monitoring of adverse side effects. Further research involving larger samples, more trials with different countries working in consortia, and unified operational definitions for diagnosis will help elaborate the clinical characteristics of late-onset psychosis and lead to the development of treatment approaches.

Associations between game use and mental health in early adulthood: A nationwide study in Korea.

BACKGROUND: The number of digital game users is increasing, and so is attention to digital gaming's effects on mental health. We aimed to reveal if risky (game addiction) and usual game use (non-risky) are associated with mental health in early adulthood. METHODS: Using data from the nationwide cross-sectional Korean Epidemic Catchment Area study for psychiatric disorders, 415 participants aged 18-30 years were divided into "non-game," "usual game," and "risky game" user groups based on the previous month's game use and cut-off value of game overuse screening questionnaire. Multiple linear and logistic regressions revealed the association between game use groups, perceived mental health, and lifetime prevalence of clinical mental disorders including suicidal ideation. RESULTS: Among the 415 participants, 167 were non-game users, 175, usual game users, and 73, risky game users. Risky game users self-reported decreased satisfaction and happiness, and a significantly higher lifetime prevalence of major depressive disorder, alcohol dependence, and suicidal ideation. Usual game users were significantly associated with higher lifetime prevalence of alcohol dependence and suicidal ideation. Self-reported happiness partially mediated between game use and lifetime suicidal ideation in risky, but not usual game users. LIMITATIONS: This study is a cross-sectional observational study which was not possible to define the temporal relationship. CONCLUSIONS: Both risky and usual game use are associated with mental health problems in early adulthood, indicating the need for careful mental health screening on not only risky game users but also usual game users.

Prevalence of lifetime psychiatric disorders and suicidality in adults with subthreshold posttraumatic stress disorder: A population-based nationwide study in Korea.

BACKGROUND: Subthreshold posttraumatic stress disorder (PTSD) is a chronic condition, and despite its clinical importance, few studies have been conducted. We investigated the relationship of subthreshold PTSD with various psychiatric disorders and suicidality in a South Korean general population. METHOD: A total of 5,102 respondents, aged at least 18 years, completed face-to-face interviews using the Korean version of the Composite International Diagnostic Interview and questionnaires for lifetime suicidal ideation, plans, and attempts. Subthreshold PTSD was defined as at least one symptom in each of the three symptom clusters (Criteria B, C, and D) and a symptom duration of ≥ 1 month (Criterion E). RESULTS: The lifetime prevalence of subthreshold PTSD (2.5%) was higher than that of PTSD (1.5%). After adjusting for sociodemographic factors, subthreshold PTSD was significantly associated with nicotine use disorders, major depressive disorder, obsessive-compulsive disorder (OCD), generalized anxiety disorder, and specific phobia. Among psychiatric disorders, the odds ratio for OCD was notably high. Subthreshold PTSD was associated with increased suicidal ideation (adjusted OR [AOR] = 2.90, 95% CI [1.98, 4.26]), suicidal plans (AOR = 3.58, [1.86, 6.89]), and suicide attempts (AOR = 3.93, [1.93, 8.01]) after adjusting for sociodemographic factors. When adjusted for sociodemographic factors and psychiatric disorders, suicidal ideation (AOR = 2.04, [1.34, 3.11]) remained statistically significant. CONCLUSION: This study found that subthreshold PTSD was associated with various psychiatric disorders and suicidality. Increased attention to the mental health of individuals with subthreshold PTSD is necessary. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The Association of Childhood Maltreatment with Adulthood Mental Disorders and Suicidality in Korea: a Nationwide Community Study.

BACKGROUND: Although childhood maltreatment is a known risk factor for adulthood mental health, the impact of different types of childhood maltreatment on mental disorders is not yet clear. This study explored the association of each type of childhood maltreatment with adulthood mental disorders and suicidality in South Korea. METHODS: A total of 5,102 individuals from the general populations over the age of 18 responded to the Korean version of the Composite International Diagnostic Interview and questions about childhood maltreatment (emotional neglect, psychological abuse, physical abuse, and sexual abuse). To evaluate the odds ratio for mental disorders and suicidality associated with each type of childhood maltreatment, we used logistic regression analysis. RESULTS: About 17.0% of the respondents reported having experienced a type of maltreatment in childhood. According to the type, 9.4% reported physical abuse, 9.3% reported emotional neglect, 7.9% reported psychological abuse, and 3.8% reported sexual abuse. Exposure to each type of childhood maltreatment was associated with most types of mental disorders after adjusting for sociodemographic factors. Each type of childhood maltreatment victim was associated with suicidality (suicidal ideations, suicide plans, and suicide attempts). Dose-response patterns for suicide attempts were observed in all types of victims. Moreover, the respondents who experienced frequent childhood emotional neglect were 14 times more likely to have attempted suicide. CONCLUSION: Childhood maltreatment was associated with mental health in adulthood. The findings show the need for early detection and intervention of victims of childhood maltreatment to minimize its negative impact on adult mental health.

Differences Between the Psychiatric Symptoms of Healthcare Workers Quarantined at Home and in the Hospital After Contact With a Patient With Middle East Respiratory Syndrome.

Objective: Although quarantine is an effective measure for the prevention of the spread of infectious diseases, it may have negative effects on the mental health of the isolated individual. During the 2015 outbreak of the Middle East Respiratory Syndrome (MERS) in Korea, healthcare workers came in contact with patients with MERS were quarantined either at home or in a hospital ward. In this study, we aimed to compare the psychiatric symptoms of these employees according to the method of quarantine. Methods: All 146 quarantined staff completed self-report questionnaires. Depressive symptoms were measured using the Patient Health Questionnaire-9, anxiety symptoms were assessed using Spielberger's State-Trait Anxiety Inventory, and acute stress disorder (ASD) symptoms were evaluated using the Stanford Acute Stress Reaction Questionnaire. Results: The in-hospital quarantine group had a higher rate of symptoms of depression (p < 0.001) and ASD (p = 0.014) than the group quarantined at home. Logistic regression analysis showed that respondents quarantined in the hospital (OR = 6.342; 95% CI 1.853-21.708) and those quarantined for longer periods (OR = 1.153, 95% CI = 1.036-1.285) had a higher risk of depressive symptoms. Conclusions: In-hospital quarantine and quarantine for longer periods increase the risk of depressive symptoms. When quarantine measures are taken, certain measures are needed to minimize the risk of psychiatric problems. Appropriate interventions should be implemented if psychiatric problems occur.

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.

Impacts of Remaining Single above the Mean Marriage Age on Mental Disorders and Suicidality: a Nationwide Study in Korea.

BACKGROUND: This study investigated the impact of getting older than the mean marriage age on mental disorders and suicidality among never-married people. METHODS: We performed an epidemiological survey, a nationwide study of mental disorders, in 2016. In this study, a multi-stage cluster sampling was adopted. The Korean version of the Composite International Diagnostic Interview was conducted with 5,102 respondents aged 18 years or above. The associations between never-married status, mental disorders, and suicidality were explored according to whether the mean age of first marriage (men = 32.8 years; women = 30.1 years) had passed. RESULTS: Never-married status over the mean marriage age was associated with agoraphobia, obsessive-compulsive disorder, mood disorders, and major depressive disorder after adjusting for sociodemographic factors. Respondents with never-married status above the mean marriage age were associated with suicide attempts (adjusted odds ratio [aOR], 3.21; 95% confidence interval [CI], 1.36-7.60) after controlling for sociodemographic factors and lifetime prevalence of mental disorders, while respondents with never-married status under the mean marriage age were not. Moreover, in respondents with never-married status, getting older than the mean marriage age was associated with suicidal ideations (aOR, 1.49; 95% CI, 1.04-2.15) and suicide attempts (aOR, 3.38; 95% CI, 1.46-7.84) after controlling for sociodemographic factors and lifetime prevalence of mental disorders. CONCLUSION: Never-married status above the mean first marriage age was associated with mental disorders and suicidality. These findings suggest the need for a national strategy to develop an environment where people with never-married status do not suffer even if their marriage is delayed.

Age-related differences in the associations among at-risk drinking, alcohol use disorder, and psychological distress across the adult lifespan: a nationwide representative study in South Korea.

PURPOSE: To investigate age-related differences in the relationships among at-risk alcohol consumption, alcohol use disorder (AUD), and psychological distress with a special focus on older adults. METHODS: We used a nationwide cross-sectional study of a representative sample of community-dwelling adults from the Korean Epidemiologic Catchment Area study for psychiatric disorders conducted by door-to-door interviews. The Korean version of the Composite International Diagnostic Interview was applied. Subjects were categorized into four age groups: young-to-middle-aged (20-54 years), near-old (55-64 years), early-old (65-74 years), and late-old (≥ 75 years). The associations among at-risk drinking, alcohol use disorder, and psychological distress were examined according to age groups. RESULTS: Among a total of 5102 individuals, half of them drank alcohol in the previous year, of whom 20.5% were at-risk drinkers (≥ 100 g/week). Older people were less often diagnosed with AUD than young-to-middle-aged adults with a similar degree of at-risk drinking. They were less likely to meet the DSM-5 AUD criteria in terms of social and vocational role disruption or creation of a physically hazardous situation. However, at-risk drinking showed a stronger association with subjective psychological distress in older adults, particularly in the near-old group (adjusted odds ratio 1.82, 95% confidence interval 1.09-3.03; p = 0.023). CONCLUSIONS: These findings indicate the importance of screening for mental health problems in older adults, especially near-old adults, who drink more than 100 g of alcohol per week even when they do not satisfy the criteria for a diagnosis of AUD.

Masseter nerve-based facial palsy reconstruction

Facial paralysis is a devastating disease, the treatment of which is challenging. The use of the masseteric nerve in facial reanimation has become increasingly popular and has been applied to an expanded range of clinical scenarios. However, appropriate selection of the motor nerve and reanimation method is vital for successful facial reanimation. In this literature review on facial reanimation and the masseter nerve, we summarize and compare various reanimation methods using the masseter nerve. The masseter nerve can be used for direct coaptation with the paralyzed facial nerve for temporary motor input during cross-facial nerve graft regeneration and for double innervation with the contralateral facial nerve. The masseter nerve is favorable because of its proximity to the facial nerve, limited donor site morbidity, and rapid functional recovery. Masseter nerve transfer usually leads to improved symmetry and oral commissure excursion due to robust motor input. However, the lack of a spontaneous, effortless smile is a significant concern with the use of the masseter nerve. A thorough understanding of the advantages and disadvantages of the use of the masseter nerve, along with careful patient selection, can expand its use in clinical scenarios and improve the outcomes of facial reanimation surgery.

Masseter nerve-based facial palsy reconstruction

Facial paralysis is a devastating disease, the treatment of which is challenging. The use of the masseteric nerve in facial reanimation has become increasingly popular and has been applied to an expanded range of clinical scenarios. However, appropriate selection of the motor nerve and reanimation method is vital for successful facial reanimation. In this literature review on facial reanimation and the masseter nerve, we summarize and compare various reanimation methods using the masseter nerve. The masseter nerve can be used for direct coaptation with the paralyzed facial nerve for temporary motor input during cross-facial nerve graft regeneration and for double innervation with the contralateral facial nerve. The masseter nerve is favorable because of its proximity to the facial nerve, limited donor site morbidity, and rapid functional recovery. Masseter nerve transfer usually leads to improved symmetry and oral commissure excursion due to robust motor input. However, the lack of a spontaneous, effortless smile is a significant concern with the use of the masseter nerve. A thorough understanding of the advantages and disadvantages of the use of the masseter nerve, along with careful patient selection, can expand its use in clinical scenarios and improve the outcomes of facial reanimation surgery.

The Association of Childhood Experience of Peer Bullying with DSM-IV Psychiatric Disorders and Suicidality in Adults: Results from a Nationwide Survey in Korea.

BACKGROUND: Few studies have examined the association between childhood bullying and adulthood mental disorders based on the Diagnostic and Statistical Manual of Mental Disorders (DSM) criteria. We investigated the association of childhood peer bullying with Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) psychiatric disorders and suicidality in adults. METHODS: A total of 5,102 respondents aged 18 or over completed the Korean version of the Composite International Diagnostic Interview for DSM-IV psychiatric disorders and a questionnaire for suicidal ideas, plans, and attempts. We evaluated peer bullying using an item in the Adverse Childhood Experiences International Questionnaire. Logistic regression analyses were used to identify the association between victimization of peer bullying, adult psychiatric disorders, and suicidality. RESULTS: Around 8.8% of the general population in Korea reported the experience of being bullied when growing up. Bullying experience was associated with an increase in the adulthood prevalence of nicotine use disorders (adjusted odds ratio [aOR], 2.47; 95% confidence interval [CI], 1.75-3.49), alcohol use disorders (aOR, 1.93; 95% CI, 1.49-2.51), mood disorders (aOR, 4.23; 95% CI, 3.01-5.94), and anxiety disorders (aOR, 2.89; 95% CI, 1.89-4.43) after adjusting for sociodemographic variables. Among anxiety disorders, the OR for post-traumatic stress disorder (aOR, 9.95; 95% CI, 5.62-17.63) was notably high. Frequent victimization (many times) was significantly associated with suicidality even after adjusting for sociodemographic variables and lifetime prevalence of psychiatric disorders, whereas occasional victimization (once or a few times) was not. CONCLUSION: Childhood bullying experience was associated with adult psychiatric disorders and suicidality. The findings indicated the importance of the early detection and management of childhood peer bullying to reduce detrimental adulthood consequences.

Prognostic Factors in Complex Regional Pain Syndrome Type 1 Occurring in the Korean Army.

OBJECTIVES: In Korea, patients diagnosed with complex regional pain syndrome (CRPS) in the army are typically discharged from the army; however, the course of the disease after discharge is not known. The purpose of this study was to investigate the course of CRPS that occurred in the army and to identify the influences of various clinical and psychosocial factors immediately before discharge on the disease course. METHODS: Clinical profiles and psychosocial status were collected from the medical records of 16 patients with CRPS type 1 who were discharged during the period between March 2017 and April 2018. The degree of improvement after discharge was assessed by follow-up evaluation through telephone contact. Cox proportional hazards regression was performed to identify clinical and psychosocial predictors for the rate of recovery. RESULTS: The median time to recovery after discharge was 39 weeks (95% confidence interval [CI] = 8.8-69.2 weeks). The sole predictor for time to recovery after discharge was the time period from the onset of pain to discharge. Each one-week increase in the duration of pain experienced in the military was associated with a 18.2% (95% CI = 5.3%-29.5%) reduction in the rate of recovery after discharge (P = 0.007). CONCLUSIONS: Patients who experienced a short period of pain in the military demonstrated a relatively good prognosis after discharge. This may show how prolonged pain in the army could affect the experience of pain from a social point of view, in that it shows the disease course after a change in the social environment.

Attachment style and filial obligation in the burden of caregivers of dementia patients.

Insecure attachment styles have been known to predict greater burden in caregivers of dementia patients. However, it has not been tested how filial obligation, which refers to one's sense of duty on helping elderly parents and is especially pronounced in Asian cultures, is involved in that relationship. We sought to identify whether the association between attachment style and caregiver burden differs according to the degree of filial obligation in caregivers of dementia patients. To assess filial obligation in Korean participants, a Korean filial obligation measure was developed. Ninety-eight Korean female caregivers of dementia patients reported their attachment style, filial obligation, burden, and patient behavioral symptoms. Patients' cognitive abilities, daily activity levels, and global dementia severities were obtained from hospital records. When adjusting for caregiver and patient characteristics, greater attachment anxiety predicted higher burden, corroborating literature findings. However, the association of attachment avoidance with burden was contingent on filial obligation: When obligation was high, greater avoidance associated with lower burden, which contrasts with previous negative implications of attachment insecurity. This implies a buffering role of attachment avoidance among those highly obligated. In addition, obligation positively predicted burden among those low in avoidance. This study is the first one to investigate and find conditional associations between attachment style, filial obligation, and caregiver burden. Given that filial obligation tends to be higher in caregivers of Eastern countries, this study provides quantitative evidence that the caregiving process may be different for them.

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.