Abstract
IMPORTANCE: Many adolescents experience sleep that is too short and mis-timed for their circadian clock, which can adversely impact psychological and physical health. Feasible, targeted interventions to modify sleep behaviors and circadian timing could improve adolescent sleep and ultimately, health, and functioning. OBJECTIVE: To determine whether a novel intervention integrating chronotherapeutic approaches (sleep scheduling, morning bright light glasses, and evening blue-light blocking glasses) would increase weeknight sleep duration and shift circadian timing earlier in adolescents with late sleep. DESIGN, SETTING, AND PARTICIPANTS: This randomized clinical trial was conducted in a research setting in an academic medical center during school months (late August to mid-June) between 2018 and 2024. All analyses were intention to treat. Adolescents aged 16 to 19 years enrolled in a traditional high school who reported habitual weekend sleep onset later than 1 am. Participants were randomized to a Sleeping Late Teens Program or sleep monitoring control. INTERVENTIONS: The Sleeping Late Teens Program included 1 collaborative, problem-solving session (<1 hour) followed by 2 weeks of a personalized sleep schedule that shifted bedtimes and wake times earlier. Participants wore morning bright-light glasses for 30 to 60 minutes on waking and amber-tinted blue light-blocking glasses for 2 hours before bed. MAIN OUTCOMES AND MEASURES: Primary outcome measures included weeknight circadian timing indexed by salivary dim-light melatonin onset (DLMO), weeknight sleep duration measured with actigraphy, and circadian alignment operationalized as the interval between DLMO and midsleep (middle of the nocturnal sleep period). RESULTS: Among 86 participants, 44 were randomly assigned to the intervention group and 42 to the control group. Of these, 80 completed baseline procedures (40 in each group): mean (SD) age, 17.5 (0.7) years; 48 female (60%) and 32 male (40%). The intervention group showed statistically significant and clinically relevant changes in sleep and circadian metrics compared with the sleep monitoring control. After 2 weeks, participants randomized to the active intervention, compared with the control, had earlier circadian timing (45 minutes; β = -0.55; 95% CI, -0.79 to -0.31; P = .003) and longer weeknight sleep duration (47 minutes; β = 0.74; 95% CI, 0.30-1.18; P = .003). DLMO-midsleep alignment shortened by 18 minutes in the intervention group compared with an 8-minute lengthening in controls; however, this difference was not statistically significant (β = -0.35; 95% CI, -0.72 to 0.02; P = .20). CONCLUSION AND RELEVANCE: In this randomized clinical trial, results show that a short-term intervention that combined sleep scheduling, morning bright-light glasses, and evening blue light-blocking glasses shifted circadian timing earlier and extended weeknight sleep duration in adolescents. Larger trials are needed to confirm the effectiveness of this intervention. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03806296.