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.
Keywords: Circadian rhythm; Geriatric assessment; Geriatric psychiatry; Sleep disorders; Validation studies; Psychometrics.