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.

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.