Evidence map›Paper›PMID 42141042›Full record

Trial reportScientific reports2026

A one-hour delayed school start improves sleep, sleepiness and inhibitory control in early adolescents in a randomized controlled trial.

Eve Reynaud, Lucie Malevergne, Alexandre Grellet, Adrien Pawlik, Marc Gurgand, Amandine E Rey, Stéphanie Mazza

Abstract readRandomized Controlled Trial
In one paragraph

Trial report in Scientific reports, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

7 authors.

Eve ReynaudCNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR 5292, FORGETTING Team, Université Claude Bernard Lyon 1, 69500, Bron, France.
Lucie MalevergneCNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR 5292, FORGETTING Team, Université Claude Bernard Lyon 1, 69500, Bron, France.
Alexandre GrelletParis School of Economics, CNRS, and Ecole normale supérieure-PSL, Paris, France.
Adrien PawlikParis School of Economics, CNRS, and Ecole normale supérieure-PSL, Paris, France.
Marc GurgandParis School of Economics, CNRS, and Ecole normale supérieure-PSL, Paris, France.
Amandine E ReyCNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR 5292, FORGETTING Team, Université Claude Bernard Lyon 1, 69500, Bron, France.
Stéphanie MazzaCNRS, INSERM, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR 5292, FORGETTING Team, Université Claude Bernard Lyon 1, 69500, Bron, France. stephanie.mazza@univ-lyon1.fr.

Funding

Agence Nationale de la Recherche ANR-21-ESRE-0034
6 · The paper itself

Abstract

Early school start times (SST) force adolescents to wake earlier than biologically preferred, creating chronic sleep debt. While evidence supports delaying SSTs, few controlled studies have used objective measures to assess their impact. We conducted a controlled intervention in a French boarding school to evaluate the effects of a one-hour delay in SST on sleep (N = 50) and cognitive functioning (N = 73) in early adolescents (age 12.8 years [11.7-14.2], 66% girls). After a baseline period with 8 a.m. starts (T0), four classes were randomized: half remained at the early schedule (Control-SST), half switched to 9 a.m. (Delayed-SST). Sleep measured by actigraphy, cognitive performance and mental health were assessed at baseline (T0) and 6 months later (T1). Between T0 and T1, total sleep time decreased in the Control-SST group, whereas the Delayed-SST group showed a modest, non-significant increase. This resulted at T1 in a 26-min between-group difference (Cohen's d = 0.93, p = 0.007). Sleep onset time did not differ between groups. Sleepiness decreased in Delayed-SST but increased in Control-SST (d = -0.52, p = 0.042). Inhibitory control improved in Delayed-SST compared to Control-SST (d = -0.79, p = 0.001), with trends toward better sustained attention (d = -0.40, p = 0.051). Delaying SST by one hour appears to mitigate the progressive reduction in sleep duration commonly observed during adolescence, and benefits both cognitive functioning and sleepiness outcomes in early adolescence.

Indexed as

SchoolsSleepSleepinessActigraphyAdolescentChildCognitionFemaleHumansMaleSleep DurationTime FactorsActigraphyAdolescentAttentionCognitionSchool start timeSleep

Identifiers

PMID42141042
PMCPMC13369917

What OpenQuestion holds

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LicenceCC BY
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Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.