Daily Variation in Adolescents’ Sleep, Activities, and Psychological Well-Being

The daily diarymethodwas used to examine the daily dynamics of adolescent sleep time, activities, and psychological well-being among an ethnically diverse sample of over 750 adolescents approximately 14–15 years of age. Studying and stressful demands during the day were modestly but consistently associated with less sleep that evening. Receiving less sleep at night, in turn, was modestly but consistently related to higher levels of anxiety, depressive feelings, and fatigue during the following day. In addition, the daily variability in adolescents’ sleep timewas notable and just as important for the youths’ average levels of daily psychological well-being as was the average amount of time spent sleeping each night. A small number of ethnic and gender differences emerged in the dynamics of adolescent sleep, activities, andwell-being.Discussion focuses on the importance of examiningvariability in adolescents’ sleep behaviors in order to better understand the implications of sleep for adolescent well-being and development.