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

April 30, 2026 updated by: University of Bergen
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

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

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

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
583

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

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

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

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

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
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

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Average sleep duration on school days
Time Frame: Baseline and at the end of the school year (at about 8 months follow-up)
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)
Time Frame: At the end of the school year (at about 8 months follow-up)
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
Time Frame: 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
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

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
School absence and academic performance (self-reported and objective)
Time Frame: 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
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
Time Frame: Baseline and at the end of the school year (at about 8 months follow-up)
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
Time Frame: Baseline and at the end of the school year (at about 8 months follow-up)
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
Time Frame: At the end of the school year (at about 8 months follow-up)
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

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Bergen

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Haukeland University Hospital

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Bjørn Bjorvatn, Department of Global Public Health and Primary Care, University of Bergen, Norway

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
August 15, 2023

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 30, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 30, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 3, 2024

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 23, 2024

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 24, 2024

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 1, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 30, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant 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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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