Actigraphic Sleep Variability is Associated With Lower Positive Mood in Adolescents

Purpose: Poor sleep health is associated with lower positive mood in adolescents, and more variable sleep is associated with more negative mood. There is a lack of research on the associations between sleep variability and positive mood in adolescents. We investigated whether several types of sleep variability, measured with actigraphy, were associated with positive mood reported on a daily diary in adolescents. Methods: Data were collected from a substudy of the Year 15 wave of the Future of Families and Child Wellbeing Study (n = 580; 53% female, mean age ± standard deviation [SD] = 15.4 ± 0.5 years, range 14.7–17.7). Adolescents wore an actigraphy device (M ± SD = 5.6 ± 1.4 nights per adolescent, range: 3–10) and completed daily diaries (M ± SD = 5.5 ± 1.4 days per adolescent, range: 3–9) for ∼1 week, where they rated their levels of happiness and excitement during that day from 0 (not at all) to 4 (extremely). Happiness and excitement were averaged into “positive mood.” Separate linear regression models assessed whether actigraphy-measured variability of sleep duration, onset, and offset (residual individual standard deviation, riSD), sleep regularity index, social jetlag, and free night catch-up sleep were associated with average positive mood per person. Analyses adjusted for age, birth sex, race/ethnicity, household income, and the primary caregiver's education level. Results: Greater variability in sleep duration (p = .011, β = −0.11) and lower sleep regularity index (p = .034, β = 0.09) were associated with lower ratings of positive mood. There were no other significant associations (p ≥ .10). Discussion: Variable and irregular sleep are associated with lower levels of positive mood in adolescence, which may increase the risk of poor emotional health in adulthood.