Bedtime Autonomy and Cellphone Use Influence Sleep Duration in Adolescents

Purpose: The aim of this study was to examine modifiable environmental contributors of shortened sleep duration in adolescents. Method: We assayed sleep duration over two weeks using actigraphy in a sample of 98 adolescents (ages 14-18, 51 female). Reports of adolescents setting their own bedtime and parental monitoring of bedtime were collected and, using principal components analysis, reduced to one factor representing bedtime autonomy. In a subsample of participants (n = 63) frequency of nighttime cellphone use and reports of cellphone disruption were assessed and combined into a composite score of cellphone usage. Results: Increasing age was associated with shorter total sleep duration, r(98) = -.28, p = .006. Age related sleep duration was mediated by bedtime autonomy, ab(cs) = -.11, 95% BC CI [-.2167, -.0370]. The effects of bedtime autonomy were moderated by nighttime cellphone use such that bedtime autonomy was most problematic for adolescents who used cellphones more frequently, B = -10.44, SE = 4.64, 95% BC CI [-21.3749, -2.8139], compared with those who used cellphones less frequently, B = -1.94, SE = 3.28, 95% BC CI [-9.8694, 3.6205]. Conclusions: Adolescence is characterized by insufficient sleep due to biological and environmental factors. Although age is frequently cited as an important element in declining sleep duration, our results suggest age may be a proxy for other co-occurring psychosocial changes during adolescence. These findings identify mechanisms by which parents and adolescents may help increase the amount of sleep adolescents achieve. (C) 2018 Society for Adolescent Health and Medicine. All rights reserved.