Demographic predictors of bedtime procrastination in the Japanese population.

UNLABELLED: Bedtime procrastination (BP) is prevalent and problematic, with no previous study conducted in Japan. This study developed the Japanese version of the Bedtime Procrastination Scale (BPS), assessed its validity, and investigated the relationship between BP, demographic features, and sleep outcomes. Participants were divided into two samples ( N  = 252 and N  = 630). Sample 1 involved a longitudinal study to confirm test-retest reliability of the BPS. Sample 2 involved a cross-sectional study to assess confirmatory factor analysis, criterion-related validity, construct validity, and determine the internal consistency of the BPS. The relationship between BP and demographic features (gender, age, and employment status) and sleep outcomes (Athens Insomnia Scale, sleep hours, sleep onset latency, and sleep efficiency) was investigated using Sample 2. The BPS showed good internal consistency (Cronbach's α coefficients = .90-91), test-retest reliability (ICC = .86), and one factor model was valid; CFI = .95, TLI = .94, RMSEA = .10, and SRMR = .04. The BPS had a moderate positive association with general procrastination, moderate negative associations with self-control, sleep quality, and sleep duration on weekdays, and those who answered "yes" to the item "Do you have trouble with bedtime procrastination?" had higher BPS scores. BPS scores were moderately higher for younger participants (≤ 40 years), slightly higher for females, and non-significantly different between employment statuses. The BPS showed a significant positive correlation with insomnia symptoms, weak positive association with sleep efficiency on weekdays and holidays, and no significant association with sleep onset latencies on holidays and weekdays. This study provides new data on demographic predictors of BP in Japan. No clear effects of gender and employment status were found, but age was a strong predictor of BP, where younger age groups had a higher BP risk.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s41105-023-00508-7.