Validation of the Korean Munich Chronotype Questionnaire.

PURPOSE: The Munich Chronotype Questionnaire (MCTQ) assesses actual sleep-wake timing and has advantages compared to prior chronotype questionnaires in that it differentiates sleep-wake patterns between work days and free days and uses corrected mid-sleep time on free days after correcting for accumulated sleep debt over the week to categorize chronotype. The current study, we validated the Korean version of the MCTQ. METHODS: In this study, 310 participants (mean age = 27.09 ± 5.64; 78.1% females) completed the Korean version of the MCTQ. RESULTS: MCTQ parameters were significantly correlated with MEQ (Morningness-Eveningness Questionnaire) scores (│r│ ≥ 0.48), and test-retest reliability was ≥ 0.72. Cutoff scores of 2.5%, which correlated to 2.36 and 8.57 mid-sleep times in our sample, showed the best convergence with MEQ when categorizing chronotype. CONCLUSIONS: Our study suggests that the MCTQ is a useful questionnaire in assessing chronotype in young adults.

Application of Diagnostic Interview for Internet Addiction (DIA) in Clinical Practice for Korean Adolescents.

The increased prevalence of Internet Gaming Disorder (IGD) and the inclusion of IGD in DSM-5 and ICD-11 emphasizes the importance of measuring and describing the IGD symptoms. We examined the psychometric properties of the Diagnostic Interview for Internet Addiction (DIA), a semi-structured diagnostic interview tool for IGD, and verified the application of DIA in clinical practice for Korean adolescents. The DIA is conducted in a manner that interviews both adolescents and their caregivers, and each item has a standardized representative question and various examples. It consists of 10 items based on the DSM-5 IGD diagnostic criteria, which is cognitive salience, withdrawal, tolerance, difficulty in regulating use, loss of interest in other activities, persistent use despite negative results, deception regarding Internet/games/SNS use, use of Internet/games/SNS to avoid negative feelings, interference with role performance, and craving. The study included 103 adolescents divided into three subgroups (mild risk, moderate risk, and addicted group) based on the total score of DIA. Demographic and clinical characteristics were compared among the DIA subgroups using the chi-square test and analysis of variance (ANOVA), and correlation analysis was used to examine the associations of IGD symptoms with clinical variables (e.g., impulsivity, aggression, depression, anxiety, self-esteem). The DIA total score was significantly correlated with Internet and smartphone addiction, depression, state anxiety, self-esteem, impulsivity, aggression, and stress. Furthermore, the moderate risk and addicted group showed significantly higher levels of Internet and smartphone addiction, anxiety, depression, impulsivity, aggression, stress, and lower self-esteem compared with the mild risk group. The Junior Temperament and Character Inventory (JTCI), which measures temperament and character traits, revealed that the mild risk group had higher levels of persistence and self-directedness than did the addicted group. Our findings confirmed the psychometric properties of DIA and the application of the DIA classifications in Korean adolescents.

Validation of the Munich ChronoType Questionnaire in Korean Older Adults.

OBJECTIVE: This study aimed to evaluate psychometric properties of the Munich ChronoType Questionnaire (MCTQ) in a sample of Korean older adults. METHODS: One-hundred ninety two participants aged 65 and over completed interview-based questionnaires about chronotype, insomnia, depression, and anxiety. Additionally, a small subset of subjects completed a 7-day sleep diary and actigraphy measurements. RESULTS: Morningness-Eveningness Questionnaire (MEQ) scores were significantly negatively correlated with Midpoint of sleep on free days corrected for sleep debt accumulated through weekdays (MSFsc) (r=-0.45, p<0.01) assessed by the MCTQ. MSFsc using the MCTQ was significantly positively correlated with MSFsc assessed by both the sleep diary (r=0.74, p<0.05) and actigraphy (r=0.76, p<0.05). Additionally, MSFsc assessed by the MCTQ was significantly positively correlated with insomnia (r=0.26, p<0.01), depression (r=0.25, p<0.01), and anxiety (r=0.18, p<0.05). Finally, based on MEQ scores, we derived a cut-off score for the MCTQ that distinguishes morning type and other types (intermediate/evening types) in older adults. CONCLUSION: The results of these studies supported the validity of the MCTQ in Korean older adults. Additionally, while sleep rhythms in elder adults may be more advanced, eveningness tendency may be still important and indicative of sleep and psychological disturbance.

Longitudinal Changes in Neural Connectivity in Patients With Internet Gaming Disorder: A Resting-State EEG Coherence Study.

Aims: The present study investigated neural connectivity associated with treatment responses in patients with Internet gaming disorder (IGD) using resting-state electroencephalography (EEG) coherence analyses. Methods: We included 30 patients with IGD and 32 healthy control subjects (HCs). Of the IGD patients, 18 completed an outpatient treatment that included pharmacotherapy with selective serotonin reuptake inhibitors for 6 months. Resting-state EEG coherence and self-report questionnaires were used to evaluate clinical and psychological features pre- and post-treatment, and data were analyzed using generalized estimating equations. Results: Compared with HCs, patients with IGD showed increased beta and gamma intrahemispheric coherence and increased delta intrahemispheric coherence of the right hemisphere at baseline. After 6 months of outpatient management, patients with IGD exhibited improvements in IGD symptoms compared with baseline, but they continued to show increased beta and gamma intrahemispheric coherence compared with that of HCs. No significant EEG coherence changes between the pre- and post-treatment assessments were detected in any band in the IGD group. Conclusion: These findings suggest that significantly greater intrahemispheric fast-frequency coherence may be an important neurophysiological trait marker of patients with IGD.

The Relationship between Impulsivity and Internet Gaming Disorder in Young Adults: Mediating Effects of Interpersonal Relationships and Depression.

Background: This study aimed to explore relationships between impulsivity, interpersonal relationships, depression, and Internet Gaming Disorder (IGD) symptoms. Methods: A total of 118 young adults participated in this study: 67 IGD patients who met five or more of the DSM-5 diagnostic criteria for IGD and 56 healthy controls. We administered questionnaires to assess IGD symptoms (Young's Internet Addiction Test; Y-IAT), impulsivity (Barratt Impulsiveness Scale; BIS-11), interpersonal relationship (Relationship Change Scale; RCS), and depression (Beck Depression Inventory; BDI). We used PROCESS macro in SPSS to perform mediation analysis. Results: IGD symptom was positively related to depression and impulsivity, and negatively related to the quality of interpersonal relationships. Mediation analysis revealed full mediation effects of interpersonal relationships and depression on the association between impulsivity and IGD symptoms in the IGD group. Specifically, even after adjusting for gender as a covariate, high impulsivity was associated with greater difficulty with interpersonal relationships; which further affected depression and increased the risk of IGD. Conclusions: These results demonstrate the importance of early intervention in IGD patients, particularly in young adults with high impulsivity. When intervening in adults' IGD, we should consider not only individual factors (e.g., depression) but also socioenvironmental factors (e.g., interpersonal relationships).

Validation of the Korean Depressive Symptom Inventory-Suicidality Subscale.

OBJECTIVE: The present study aimed to validate a Korean version of the self-report Depressive Symptom Inventory-Suicidality Subscale (DSI-SS). METHODS: 553 South Korean undergraduate students (aged 18-34 years, 74.8% females) completed questionnaires. Participants completed Korean versions of the self-report Depressive Symptom Inventory-Suicidality Subscale (DSI-SS), Beck Depression Inventory-II (BDI-II), Insomnia Severity Index (ISI), Beck Scale for Suicide Ideation (BSS), and a measure of suicide-related symptom history. RESULTS: Results indicated that the DSI-SS demonstrated excellent internal consistency (α=0.93) and strong convergent validity with the BDI (r=0.57, p<0.01), ISI (r=0.27, p<0.01), and BSS (r=0.70, p<0.01). DSI-SS scores also significantly differentiated between those reporting a history of suicide attempts compared to non-suicide attempters [t (38.80)=-3.28, p<0.05]. CONCLUSION: Given the brevity of this measure, and evidence for its validity, the Korean version of the DSI-SS may be particularly promising for clinical and empirical use as a screening tool among South Korean undergraduates.