Effects of Delayed School Start Times on Sleep, Mental Health, and Academic Performance Among Norwegian Adolescents

The aim is to investigate whether later school start times have positive effects on high school students' sleep patterns, mental health and daytime functioning.

Study Overview

• Status: Completed
• Conditions: Sleep; Psychiatric Disorder; Sleep Disorders, Circadian Rhythm; Sleepiness, Daytime
• Intervention / Treatment: Behavioral: Delayed school start time

Detailed Description

The current study is a randomized controlled study investigating whether later school start times on Mondays and Tuesdays have positive impact on high school students' sleep patterns, mental health, and daytime functioning. 1st year high school students are randomly assigned to classes starting either two hours later on Mondays and one hour later on Tuesday and ordinary school start times (8:15 ± 15 min) for the rest of the week, or to classes starting at regularly school start times (8:15 ± 15 min.) all weekdays. The students will be invited to respond to a web-based survey assessing sleep, mental health, and daytime functioning by the beginning and end of the school year. Official school grades and school absence data will be collected through the county administration for consenting students. Cognitive tests and objective sleep record through Somnofy are planned for a subgroup by the end of the 2024-25 school year. The study will last for two school years and involve two different cohorts of 1st year high school students.

• Study Type: Interventional
• Enrollment (Actual): 583
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Norway
  • Vestland
    • Bergen, Vestland, Norway, 5019
      • University of Bergen

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• 1st year high school students at study preparatory program of participating schools

Exclusion Criteria:

• Parent consent not obtained/documented for participants under 16 years

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Delayed school start times on Mondays and Tuesdays (intervention condition); Two hour delay in school start time on Mondays and one hour delay on Tuesdays. Ordinary school start time (8:15 ± 15 min) for the rest of the week.	Behavioral: Delayed school start time; The intervention group will start school two hours later on Mondays (at 10.15 ± 15 min) and one hour later on Tuesdays (9.15 ± 15 min) and to ordinary school start time (8.15 ± 15 min) for the rest of the week
No Intervention: Ordinary school start time all weekdays (control condition); Ordinary school start time (8:15 ± 15 min) all school days

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Average sleep duration on school days	Average sleep duration across the arms will be calculated using the Munich ChronoType Questionnaire (MCTQ), adjusted for nocturnal awakenings	Baseline and at the end of the school year (at about 8 months follow-up)
Preferred school start time (late vs. early Mondays and Tuesdays)	A conditioned item asking how satisfied the students are starting early or later on Mondays and Tuesdays, or ranging from "Very satisfied" to "very dissatisfied", will be included.	At the end of the school year (at about 8 months follow-up)
Daytime sleepiness on school days	Daytime sleepiness will be assessed based on the Karolinska Sleepiness Scale (KSS; adjusted to target sleepiness on each weekday) and The Chinese adolescent daytime sleepiness scale (CADSS).	CADSS: Baseline and at the end of the school year (at about 8 months follow-up). KSS: At the end of the school year (at about 8 months follow-up)-up

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
School absence and academic performance (self-reported and objective)	Data gathered from school authorities.	Self-reported data: Baseline and end of school year. Objective data: At the end of the school year (at about 8 months follow-up)-up
Mental health	Anxiety and depression will be assessed during the past two weeks using the Generalized Anxiety Disorder-7 and the Patient Health Questionnaire-9, respectively.	Baseline and at the end of the school year (at about 8 months follow-up)
Social jetlag	Social jetlag, calculated as the discrepancy in sleep timing on free vs. weekdays, will be calculated based on the MCTQ	Baseline and at the end of the school year (at about 8 months follow-up)
Sleep duration, school days with early vs. late start	Sleep duration for late starting days will be compared with early starting days	At the end of the school year (at about 8 months follow-up)

Collaborators and Investigators

• Sponsor: University of Bergen
• Collaborators: Haukeland University Hospital
• Investigators: Principal Investigator: Bjørn Bjorvatn, Department of Global Public Health and Primary Care, University of Bergen, Norway

Study record dates

Study Major Dates

• Study Start (Actual): August 15, 2023
• Primary Completion (Actual): June 30, 2025
• Study Completion (Actual): June 30, 2025

Study Registration Dates

• First Submitted: July 3, 2024
• First Submitted That Met QC Criteria: October 23, 2024
• First Posted (Actual): October 24, 2024

Study Record Updates

• Last Update Posted (Actual): May 1, 2026
• Last Update Submitted That Met QC Criteria: April 30, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Nervous System Diseases; Sleep Wake Disorders; Sleep Disorders, Intrinsic; Dyssomnias; Chronobiology Disorders; Occupational Diseases; Mental Disorders; Sleep Disorders, Circadian Rhythm; Disorders of Excessive Somnolence
• Other Study ID Numbers: REK Vest 606094

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No