Abstract
OBJECTIVE: Short sleep and evening phase preference associate with impaired self-control, yet few studies have assessed the efficacy of sleep extension for improving this behavioral domain. Thus, this secondary analysis of a behavioral sleep intervention measured whether an intervention that enhanced children's sleep also affected self-control. Differences by chronotype were also explored. METHODS: Sixty-seven children (8-11 yr), who reportedly slept <9.5 hr/d, were randomized to either a control or sleep intervention condition (i.e., 4-session behavioral intervention to enhance sleep by 1-1.5 hr/night). Chronotype was assessed using the Child Chronotype Questionnaire at baseline, and self-control was assessed using the Self-Control Rating Scale (SCRS, a caregiver report) at baseline and 8 weeks postrandomization. Total sleep time (TST) was measured using wrist actigraphy for 1 week at both baseline and 8 weeks postrandomization. Partial correlations and mixed-model ANOVAs were used for statistical analyses, with age as a covariate. RESULTS: At baseline, children with shorter TST (r = -0.29, p = 0.02) and an evening preference (r = 0.26, p = 0.049) were perceived as having lower self-control by their caregivers. Significant condition*time interaction effects were found for TST ( p < 0.001) and SCRS score ( p = 0.046): From baseline to follow-up, children randomized to the sleep intervention exhibited a significant increase in TST and were perceived as having greater self-control by their caregiver; children randomized to the control condition exhibited no change in TST or in SCRS score. The condition*chronotype*time interaction effect was not significant. CONCLUSION: A brief sleep intervention that enhanced TST also resulted in enhanced caregiver reported self-control in school-age children. Results add to the growing evidence for the importance of sleep health in children.