Abstract Bedtime procrastination (BP) has been identified as a significant factor contributing to poor sleep health. While previous studies have examined its behavioral and psychological correlates, its functional role in individuals with clinical insomnia remains unclear. This study aims to investigate the primary functions of BP in individuals with insomnia and examine its relationship with smartphone use. A total of 80 young adults (mean age 22.3 ± 2.4 years, 80% female) with clinical insomnia participated in the study. BP, insomnia severity, and emotion regulation were assessed using self-report questionnaires. Additionally, sleep patterns were monitored using a daily sleep diary and actigraphy. A structured interview using functional analysis was conducted to analyze the individual functions of BP, classifying responses into seven categories based on antecedents, behaviors, and consequences. Participants spent an average of 95.9 (SD = 38.3) minutes per day using their smartphones in the three hours before bedtime. Most participants used their phones every day during this window (78.6%). The most common functions of BP were emotion regulation (49.3%), reward (14.3%), and sleep induction (10.7%). In addition, adaptive emotion regulation strategies significantly moderated the relationship between BP and smartphone use in the three hours before bedtime (β = 0.34, 95%CI = 0.02 ~ 0.23). Our findings suggest that for individuals with clinical insomnia, BP, which is largely driven by smartphone use, can serve as a tool for emotion regulation. Interventions targeting BP should incorporate strategies considering individual functions of BP, rather than merely restricting media use.
Lee et al. (2026) studied this question.