PeerScreen Trial - Reducing Screen Media Use in Peer-groups of Young People

Effects of Reducing Screen Media Use on Mental Health, Sleep, Physical Activity, Heart Rate Variability, and Behavioral Patterns in Peer-groups of Young People: A Study Protocol for a Cluster-randomized Controlled Trial

The purpose of the PeerScreen trial is to investigate whether reducing screen media use affects mental health, social interaction, sleep, physical activity, heart rate variability, and behavioral patterns in young people aged 13 to 24 years. The primary question the trial aims to answer is:

Does reducing screen media use over a 4-week period improve mental health among young people?

Researchers will compare a screen media reduction intervention with a control condition in which participants continue their usual screen media use to determine whether reducing screen media use leads to improvements in mental health.

Participants will:

• be allocated to either a 4-week screen media reduction intervention or a control condition
• complete a study protocol including questionnaire-based assessments, daily self-reports, and objective monitoring of screen media use, sleep, physical activity, heart rate variability, social interactions, and geolocation

Study Overview

• Status: Not yet recruiting
• Conditions: Physical Activity; Stress; Sleep; Mental Health; Social Interaction
• Intervention / Treatment: Behavioral: Screen media reduction

Detailed Description

The PeerScreen trial is a parallel-group cluster-randomized controlled trial in which peer groups of adolescents and young adults aged 13-24 years are randomized to either a four-week screen media reduction intervention or a control condition. Random allocation of each peer group will occur after completion of a 14-day baseline assessment protocol. Randomization will be conducted using computer-generated block randomization (block sizes 2-6), stratified by mean peer group age (<18 vs. ≥18 years). In practice, a researcher will log in to an online platform and click "randomize," thereby ensuring allocation concealment.

Participants in the intervention group will be instructed to reduce smartphone use to one hour per day, limit television, computer, and tablet use to 14 hours per week, and keep screen media devices outside the bedroom.

The target sample is 80 peer groups (2-6 peers per group) of adolescents (13-17 years) and young adults (18-24 years), to be recruited via a separate survey study. This survey will be conducted in classes across secondary and higher educational institutions (e.g., secondary schools, high schools, vocational schools, university colleges, and universities) and will describe screen media behaviors among Danish youth. Before administration of the survey, the research team will introduce the PeerScreen trial in each class. At the end of the survey, students will be asked whether they are interested in participating in an experimental study and whether the research team may contact them for follow-up. Written information about the experiment will be provided to interested students during classroom visits and distributed via the school and its online platforms, along with a registration link, after the visits. This procedure will allow students to express interest at a later stage if preferred.

Data collection will combine questionnaires on mental health and well-being, daily reports of mood, sleepiness, and social interactions, and objective monitoring of screen media use, sleep, physical activity, and heart rate variability using a custom application and a wearable device. Bluetooth beacon data will be used to assess social interactions objectively, and geolocation data will be used to provide contextual information about these interactions.

• Study Type: Interventional
• Enrollment (Estimated): 240
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Jesper Schmidt-Persson, PhD; Phone Number: +4565502054; Email: jespedersen@health.sdu.dk
• Study Contact Backup: Name: Anne K Gejl, PhD; Phone Number: +4565507908; Email: akgejl@health.sdu.dk

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Participants must have at least 2 hours/day of self-reported smartphone use during leisure time (data from the survey study)
• Members of each participant's household must be willing to support the participant in adhering to the prescribed intervention (data from recruitment interview)
• Participants must have enough discretionary leisure time for possible in-person activities on a weekly basis throughout the study period (verified at the information meeting)

Exclusion Criteria:

• Participants with no smartphone will be excluded (data from recruitment interview)
• Participants with no social media profiles will be excluded (data from recruitment interview)
• Participants who currently participate in other experimental studies will be excluded (data from recruitment interview)
• Participants who have been hospitalized or prescribed sick leave within the past 3 months due to a mental illness will be excluded (data from recruitment interview)

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Screen media reduction; Peer groups randomized to the intervention will undergo a four-week screen media reduction.	Behavioral: Screen media reduction; Participants will reduce their recreational screen media use across devices. For smartphone use, participants will be asked to reduce their use to a maximum of 1 hour/day. Because social media use will not be permitted on computers or tablets during the intervention, this limit will also encompass participants' social media use. Research staff will help each participant set up smartphone app limits for the ten most used social media and gaming applications, add a widget to their home screen showing the current amount of time they have spent on their phone, and turn off non-essential notifications. For television, computer and tablet use, participants will reduce their use to 14 hours/week (with no specific daily limit), but social media use is not allowed on these devices. We will recommend participants to particularly reduce their solitary screen media use. Participants will be asked to keep their devices outside the bedroom, and they will be provided with a free alarm clock.
No Intervention: Usual screen media use (control); Participants allocated to the control group will be asked not to change their use of screen media devices and continue with their usual screen media behaviors. At the randomization meeting, if a peer group is allocated to the control condition, a researcher will explain the importance of the control group for ensuring the validity of the trial, with the aim of keeping these groups motivated and engaged. Participants in the control group will be offered the screen media reduction intervention after completing the long-term follow-up. Accordingly, they will function as a waitlist control group, although no outcome data will be collected during their subsequent intervention period.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in mental wellbeing on the Warwick-Edinburgh Mental Wellbeing Scale (WEMWBS)	Self-reported mental well-being assessed as change in total score on the 14-item Warwick-Edinburgh Mental Wellbeing Scale (WEMWBS). Total scores range from 14 to 70 points. Higher scores indicate better mental well-being.	From baseline (day 1) to post-intervention (day 42).

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in total weekly duration of face-to-face social interaction with peer-group members measured by Bluetooth Low Energy (BLE) beacon proximity events	Face-to-face social interaction with peer-group members will be assessed as the total duration of proximity events, expressed in minutes per week, using Bluetooth Low Energy (BLE) beacon data collected via the SDU Connect application. The application logs the frequency and duration of proximity events between participants within a predefined distance threshold. The outcome measure is the change in weekly minutes of peer-group proximity from the 14-day baseline period before randomization to the final 21 days of the intervention period.	From the 14-day baseline period before randomization to the final 21 days of the 4-week intervention period
Change in average weekly frequency of self-reported face-to-face social interactions with non-household, non-peer individuals	Face-to-face social interactions with individuals outside the participant's household and peer group will be assessed using daily self-report collected via the SDU Connect application. These interactions include, for example, family members not living in the household, other friends, and other relations. The outcome measure is the change in the average weekly frequency of self-reported face-to-face social interactions from the 14-day baseline period before randomization to the final 21 days of the intervention period.	From the 14-day baseline period before randomization to the final 21 days of the 4-week intervention period
Change in average nightly total sleep time measured by Garmin Venu 4	Total sleep time will be assessed using continuous monitoring with the Garmin Venu 4 wearable device. Total sleep time will be derived using the device's sleep algorithm and expressed as average minutes of sleep per night. The outcome measure is the change in average nightly total sleep time from the 14-day baseline period before randomization to the final 21 days of the 4-week intervention period.	From the 14-day baseline period before randomization to the final 21 days of the 4-week intervention period.
Change in average daily step count measured by Garmin Venu 4	Physical activity will be assessed using continuous monitoring with the Garmin Venu 4 wearable device. Physical activity will be expressed as average number of steps per day derived from the device. The outcome measure is the change in average daily step count from the 14-day baseline period before randomization to the final 21 days of the 4-week intervention period.	From the 14-day baseline period before randomization to the final 21 days of the 4-week intervention period

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in average nocturnal heart rate variability measured by Garmin Venu 4 (root mean square of successive differences)	Heart rate variability during sleep will be assessed using continuous monitoring with the Garmin Venu 4 wearable device. Heart rate variability will be expressed as the root mean square of successive differences (RMSSD) in milliseconds (ms), derived from the device during sleep periods. The outcome measure is the change in average nocturnal RMSSD from the 14-day baseline period before randomization to the final 21 days of the 4-week intervention period.	From the 14-day baseline period before randomization to the final 21 days of the 4-week intervention period.
Change in average nightly Garmin Sleep Score measured by Garmin Venu 4	Sleep quality will be assessed using the Garmin Sleep Score (proprietary overall sleep score) derived from continuous monitoring with the Garmin Venu 4 wearable device. Garmin Sleep Score is a device-derived composite sleep measure ranging from 0 to 100 points, with higher scores indicating better sleep quality. The outcome measure is the change in average nightly Garmin Sleep Score from the 14-day baseline period before randomization to the final 21 days of the 4-week intervention period.	From the 14-day baseline period before randomization to the final 21 days of the 4-week intervention period
Change in average daily minutes of moderate-to-vigorous physical activity measured by Garmin Venu 4	Physical activity intensity will be assessed using continuous monitoring with the Garmin Venu 4 wearable device. Moderate-to-vigorous physical activity will be expressed as average minutes per day spent participating in moderate-to-vigorous intensity physical activity, derived from the device. The outcome measure is the change in average daily minutes of moderate-to-vigorous physical activity from the 14-day baseline period before randomization to the final 21 days of the 4-week intervention period.	From the 14-day baseline period before randomization to the final 21 days of the 4-week intervention period.
Change in dyadic physiological synchrony in heart rate during peer co-presence measured by Bluetooth Low Energy (BLE) beacons and Garmin Venu 4	Physiological synchrony will be assessed as similarity in heart rate time series between dyads of peer-group members during periods of co-presence identified by Bluetooth Low Energy (BLE) beacon data. Heart rate will be measured continuously using Garmin Venu 4 wearable devices. Synchrony will be quantified using a Time Warp Edit Distance (TWED)-based dissimilarity measure applied to dyadic heart rate time series during beacon-defined co-presence periods, with lower dissimilarity indicating greater physiological synchrony. The outcome measure is the change in average dyadic heart rate synchrony from the 14-day baseline period before randomization to the final 21 days of the 4-week intervention period.	From the 14-day baseline period before randomization to the final 21 days of the 4-week intervention period.
Change in self-reported perceived stress score measured by the 4-item Cohen Perceived Stress Scale (PSS-4)	Perceived stress will be assessed using the 4-item Cohen Perceived Stress Scale (PSS-4). The PSS-4 total score will be used, with higher scores indicating greater perceived stress. Outcome data will be collected at baseline, post-intervention, and long-term follow-up.	Baseline (day 1), post-intervention (day 42), and long-term follow-up (day 70)
Change in self-reported social connectedness score measured by the Friendship Scale	Social connectedness will be assessed using the Friendship Scale. The outcome measure is the total Friendship Scale score at baseline (Day 1), post-intervention (Day 42), and long-term follow-up (Day 70). Higher scores indicate greater social connectedness.	Baseline (day 1), post-intervention (day 42), and long-term follow-up (day 70)
Change in self-reported loneliness score measured by the UCLA 3-Item Loneliness Scale	Loneliness will be assessed using the UCLA 3-Item Loneliness Scale. The outcome measure is the total UCLA 3-Item Loneliness Scale score at baseline (Day 1), post-intervention (Day 42), and long-term follow-up (Day 70). Higher scores indicate greater loneliness.	Baseline (day 1), post-intervention (day 42), and long-term follow-up (day 70)
Change in self-reported life satisfaction score measured by Cantril's Ladder	Life satisfaction will be assessed using Cantril's Ladder. The outcome measure is the self-reported Cantril's Ladder score at baseline (Day 1), post-intervention (Day 42), and long-term follow-up (Day 70). Higher scores indicate greater life satisfaction.	Baseline (day 1), post-intervention (day 42), and long-term follow-up (day 70)
Change in self-reported depressive symptoms score measured by the Mood and Feelings Questionnaire Short Form (MFQ-SF)	Depressive symptoms will be assessed using the Mood and Feelings Questionnaire Short Form (MFQ-SF). The outcome measure is the total MFQ-SF score at baseline (Day 1), post-intervention (Day 42), and long-term follow-up (Day 70). Higher scores indicate greater depressive symptom severity.	Baseline (day 1), post-intervention (day 42), and long-term follow-up (day 70)
Change in self-reported anxiety symptoms score measured by the Generalized Anxiety Disorder 2-Item scale (GAD-2)	Anxiety symptoms will be assessed using the Generalized Anxiety Disorder 2-Item scale (GAD-2). The outcome measure is the total GAD-2 score at baseline (Day 1), post-intervention (Day 42), and long-term follow-up (Day 70). Higher scores indicate greater anxiety symptom severity.	Baseline (day 1), post-intervention (day 42), and long-term follow-up (day 70)
Change in self-reported sleep disturbance score measured by the PROMIS Pediatric Sleep Disturbance Short Form 8a	Sleep disturbance will be assessed using the PROMIS Pediatric Sleep Disturbance Short Form 8a. The outcome measure is the total PROMIS Pediatric Sleep Disturbance Short Form 8a score at baseline (Day 1), post-intervention (Day 42), and long-term follow-up (Day 70). Higher scores indicate greater sleep disturbance.	Baseline (day 1), post-intervention (day 42), and long-term follow-up (day 70)
Change in self-reported problematic smartphone use score measured by the Smartphone Addiction Scale-Short Version (SAS-SV)	Problematic smartphone use will be assessed using the Smartphone Addiction Scale-Short Version (SAS-SV). The outcome measure is the total SAS-SV score at baseline (Day 1), post-intervention (Day 42), and long-term follow-up (Day 70). Higher scores indicate greater problematic smartphone use.	Baseline (day 1), post-intervention (day 42), and long-term follow-up (day 70)
Change in daily self-reported mood score measured by a visual analogue scale (VAS)	Mood will be assessed using a self-reported visual analogue scale (VAS) administered daily during the 14-day baseline period before randomization and daily during the 42-day intervention period. The outcome measure is the change in daily mood scores from the 14-day baseline period before randomization to the final 21 days of the intervention period, with higher scores indicating more positive mood.	Daily during the 14-day baseline period before randomization and daily during the 42-day intervention period.
Change in daily self-reported stress score measured by a visual analogue scale (VAS)	Stress will be assessed using a self-reported visual analogue scale (VAS) administered daily during the 14-day baseline period before randomization and daily during the 42-day intervention period. The outcome measure is the change in daily stress scores from the 14-day baseline period before randomization to the final 21 days of the intervention period, with higher scores indicating greater perceived stress.	Daily during the 14-day baseline period before randomization and daily during the 42-day intervention period.
Change in daily self-reported sleepiness score measured by a visual analogue scale (VAS)	Sleepiness will be assessed using a self-reported visual analogue scale (VAS) administered daily during the 14-day baseline period before randomization and daily during the 42-day intervention period. The outcome measure is the change in daily sleepiness scores from the 14-day baseline period before randomization to the final 21 days of the intervention period, with higher scores indicating greater sleepiness.	Daily during the 14-day baseline period before randomization and daily during the 42-day intervention period.

Collaborators and Investigators

• Sponsor: University of Southern Denmark
• Investigators: Principal Investigator: Anders Grøntved, PhD, University of Southern Denmark

Study record dates

Study Major Dates

• Study Start (Estimated): April 15, 2026
• Primary Completion (Estimated): December 31, 2027
• Study Completion (Estimated): December 31, 2027

Study Registration Dates

• First Submitted: March 26, 2026
• First Submitted That Met QC Criteria: April 8, 2026
• First Posted (Actual): April 15, 2026

Study Record Updates

• Last Update Posted (Actual): April 15, 2026
• Last Update Submitted That Met QC Criteria: April 8, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: physical activity; sleep; adolescent; young adult; mental health; youth; heart rate variability; screen time; well being; social interaction; peer group; digital media use; behavioral pattern; screen media use; interpersonal synchrony
• Additional Relevant MeSH Terms: Behavior; Personal Satisfaction; Psychological Well-Being; Motor Activity
• Other Study ID Numbers: S-20250078

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Access to anonymized individual participant data will be shared with other researchers for research purposes only and only upon reasonable request.
• IPD Sharing Access Criteria: Researchers will be asked to write a proposal described how data will be used. They will be able to access data by writing an email to the corresponding author.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE

Drug and device information, study documents

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