Abstract
BACKGROUND: There is growing evidence for the role of circadian factors in adolescents' sleep and academic adjustment, with greater evening preference being linked to poorer academic functioning. However, studies have yet to evaluate this association prospectively in adolescence, nor have studies examined daytime sleepiness as a putative mechanism linking evening preference to poor academic functioning. The current study used a multi-informant design to test the prospective association of evening circadian preference, daytime sleepiness, and academic functioning (e.g., global academic impairment and grades) across 2 years in adolescence. As evening circadian preference, sleepiness, and academic problems are elevated in adolescents with ADHD, we used a sample enriched for adolescents with ADHD and explored whether ADHD moderated effects. METHOD: Participants were 302 adolescents (M(age) = 13.17 years; 44.7% female; 81.8% White; 52% with ADHD). In the fall of eighth grade, adolescents reported on their circadian preference, and in the fall of ninth grade, adolescents and parents completed ratings of daytime sleepiness. In the middle of 10th grade, parents and teachers reported on adolescents' academic impairment and at the end of 10th grade, adolescents' grade point average (GPA) was obtained from school records. RESULTS: Above and beyond covariates (e.g., adolescent sex, ADHD status, medication, sleep duration) and baseline academic impairment, greater self-reported evening preference in 8th grade predicted increased parent ratings of academic impairment in 10th grade indirectly via adolescent and parent ratings of daytime sleepiness in 9th grade. Furthermore, evening preference in 8th grade predicted greater teacher ratings of academic impairment and lower average GPA in 10th grade via parent ratings of daytime sleepiness in 9th grade, controlling for covariates and baseline GPA. ADHD status did not moderate indirect effects. CONCLUSION: Findings underscore daytime sleepiness as a possible intervening mechanism linking evening preference to poor academic functioning across adolescence. Intervention studies are needed to evaluate whether targeting circadian preference and sleepiness improves academic functioning in adolescents.