IMPORTANCE: Sleep behavior markedly shifts in adolescence, increasing vulnerability to mental health disorders. Although sleep health is understood to be multidimensional, adolescent-specific sleep health dimensions have not been empirically validated and their relevance to transdiagnostic mental health outcomes is unknown.
OBJECTIVE: To identify sleep health dimensions using Fitbit devices in a large sample of young adolescents and assess concurrent and prospective associations between sleep health dimensions and transdiagnostic mental health outcomes.
DESIGN, SETTING, AND PARTICIPANTS: Multicenter longitudinal cohort study using data from 3393 participants in the Adolescent Brain Cognitive Development (ABCD) Study (Data Release 5.1, collected 2018-2020), including early adolescents (ages 11-13 years) within the US. Exploratory factor analysis (EFA) was used to identify sleep health dimensions and confirmatory factor analysis (CFA) to confirm the factor structure in an independent subsample. Linear mixed-effects models were used to test concurrent and prospective associations between sleep dimensions and mental health outcomes at 1-year follow-up. Statistical analysis was conducted from January to November 2025.
EXPOSURES: Objective sleep data collected for up to 21 (range, 7-21) days, using wearable Fitbit devices.
MAIN OUTCOMES AND MEASURES: Transdiagnostic mental health outcomes assessed via the Child Behavior Checklist and Brief Problem Monitor (internalizing and externalizing symptoms), Prodromal Questionnaire-Brief Child Version (psychoticlike symptoms), and 10-item Mania Scale (mania symptoms).
RESULTS: The 3393 participants (49% female; median age, 12 years) were split into EFA and CFA subsamples. Six sleep factors were identified using EFA: irregularity, timing, social jetlag, duration, weekend oversleep, and continuity. CFA confirmed this factor structure. All variables loaded strongly (≥0.64) onto at least 1 factor (factor 1 loadings, 0.64-0.98; factor 2, 0.96-0.98; factor 3, 0.95-0.97; factor 4, -0.86 to 1.01; factor 5, 0.68-0.93; factor 6, 0.82-0.94). Greater sleep irregularity was associated with transdiagnostic mental health symptoms cross-sectionally, but not prospectively (β, 0.06 [95% CI, 0.02-0.10] to 0.12 [95% CI, 0.08-0.16]). Shorter duration was associated with total, internalizing, externalizing, and attention symptoms cross-sectionally (β, -0.06 [95% CI, -0.10 to -0.01] to -0.11 [95% CI, -0.15 to -0.06]) and total, attention, and psychotic symptoms 1 year later.
CONCLUSIONS AND RELEVANCE: In this study, wearable Fitbit data provide empirical support for multidimensional frameworks of sleep health in adolescence. Although effect sizes were small, sleep irregularity and duration emerged as key dimensions with relevance to mental health. These findings establish a foundation for future investigations, including examining within-person patterns of the 6 dimensions, extending to older adolescence, investigating associations with other health outcomes, replicating with research-grade actigraphy devices, and suggesting potential targets for pediatric sleep interventions.
