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

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.

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)