Toward Earlier Bedtimes: Randomized Trial of Multi-Method Interventions in a Community Cohort of Adolescents

Many adolescents develop very late circadian rhythms, indicating delayed sleep phase. Interventions are sparse, and the stability of any improvements is rarely reported. To evaluate how late sleep patterns can be improved, we performed a randomized control trial among adolescents. Overall, 4-6-week intervention modes included bright light therapy (BLT), personalized sleep coaching, or their combination (BLSC), and an active control group receiving information.

We measured the sleep and circadian patterns of 288 adolescents (17 years) born in years 1999-2000. A sub-sample (n = 176) that weighted on late sleep rhythms participated in the randomized control trial. Sleep, circadian temperature patterns, depressive symptoms, anxiety, and sleep hygiene were measured at baseline (T1) after the intervention (T2) and after 1 year (T3) with GeneActiv Original actigraphy, ibutton 1922L thermologgers, and validated questionnaires.

Participants in the SC group significantly increased their sleep duration compared to the control group, 23 minutes from T1 to T2 and 33 minutes from T1 to T3 (p < .03). They also improved their sleep hygiene from T1 to T2 (p = .019), but this did not persist to T3. Other groups did not improve their sleep patterns.

Although personalized sleep coaching resulted in persistently longer sleep, none of the interventions were successful in overcoming late sleep rhythms among an adolescent sample derived from the population register. Delayed sleep phase is a persistent condition with biological components, and a 4-week intervention is presumably too short for changing sleep behavior and rhythms. Clinical Trials number 1287174/NCT02964598.