Screen TimePHX_2022_1NCT07293208
Characterization of Smartphone-related Diseases Using the Phonix Care Application
An observational study of Screen Time, run by Phonix Health at 1 site in France.
Trial summary
The goal of this observational study is to describe how adolescents and young adults use screens in their daily lives and to identify different profiles of screen use ranging from low to excessive. The study also aims to understand how screen-use behaviors relate to health, motivation, and sociodemographic factors. Read more about this study
- Who is it for?
- Ages 12 to 25 yearsHealthy volunteers can take part
- Conditions the study is for
- Screen Time
- What is being tested?
- PhonixDiag Smartphone Monitoring Tool
- Type of treatment
- Medical device
- How many people
- 171 participants
- Where
- 1 siteFrance
- Study dates
- 1 Apr 2022to 1 Mar 2023
- How long will I take part?
- 1 Month
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 12 to 25 years
- All sexes
- Healthy volunteers accepted
- Child, Adult
Study population: Participants were recruited from secondary schools and universities in Grenoble, France, through institutional communication channels and digital platforms. Recruitment occurred within educational settings located in various regions, allowing inclusion of adolescents and young adults enrolled in middle school, high school, or university programs.
Who may be able to join
- Own an Android smartphone
- Have at least 200 MB of storage on your smartphone
- Be in middle school, high school, or university
- Be enrolled in a school within the Grenoble academy district
Who cannot join
- Own an iPhone
- Participate in an interventional study in the field within the last six months
- Not sign the consent form
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Characterization of Smartphone User Profiles (Caractérisation de Profils d'Utilisateurs de Smartphone)
The goal of this observational study is to describe how adolescents and young adults use screens in their daily lives and to identify different profiles of screen use ranging from low to excessive. The study also aims to understand how screen-use behaviors relate to health, motivation, and sociodemographic factors.
The main questions it aims to answer are:
Read more
What are the objective and self-reported patterns of screen use (e.g., frequency of use, types of apps, daily time spent, usage periods)?
Do distinct screen-use profiles emerge (low, moderate, intensive/excessive) when taking into account:
Age, gender, educational track (general, technological, vocational), Parents' socioeconomic status, Health variables (sleep quality, physical activity/sedentary behavior, well-being), Cognitive and conative variables (self-regulation capacity, academic motivation)? Are excessive users characterized by specific patterns, such as intensive use of social media, video platforms, or video games combined with mood problems, sleep difficulties, or motivational issues? Do screen-use profiles vary depending on age group (middle school, high school, university) and gender?
Are there mediating mechanisms explaining excessive use? Specifically:
Does poor self-regulation mediate the link between screen-use intensity and well-being? Do sleep problems mediate the link between excessive nighttime use and mood disturbances (anxiety, depression)? Do academic motivation and cognitive factors mediate differences between moderate and excessive users? If groups differ, researchers will compare low-use, moderate-use, and excessive-use profiles to determine whether they show meaningful differences in health, motivation, and sociodemographic characteristics.
Participants will:
Install a smartphone application that passively records daily screen-use indicators (e.g., usage time, app categories, frequency of openings, time windows of use).
Complete questionnaires assessing:
Self-reported screen use, Sleep, physical activity, well-being, Mood variables (anxiety, depression), Self-regulation, Academic motivation, Sociodemographic factors (age, gender, parents' SES, educational track).
- Conditions
- Screen Time
- Being tested
- PhonixDiag Smartphone Monitoring Tool
- Keywords
- smartphone, problematic digital use, depression, academic motivation, young adult, adolescent, digital phenotyping
- Medical subject headings
- Depression
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
PhonixDiag Smartphone Monitoring ToolDevice
Also called PhonixDiag App
PhonixDiag is a passive smartphone-based monitoring tool designed to collect objective digital behavior indicators in real time. The tool runs in the background of the participant's smartphone and records daily screen-use patterns, including frequency of app openings, time spent on recreational applications, usage periods throughout the day, and nighttime phone activity. PhonixDiag does not modify the participant's phone use or deliver any behavioral intervention. It functions solely as a data collection system to objectively assess screen-use behaviors and identify usage profiles (low, moderate, excessive). The tool is distinct from other digital interventions because it does not provide feedback, warnings, or recommendations, and operates exclusively for passive monitoring purposes.
What is being measured
The primary outcome is the main question the study is designed to answer.
Objective Screen Use Time (Daily Median Over Monitoring Period)
Objective screen-use time will be measured using the PhonixDiag smartphone monitoring tool. The outcome corresponds to the median daily duration (in minutes) spent on smartphone applications across the full monitoring period. This includes all app categories and reflects real-world behavioral engagement with digital media. The measure will be used to classify participants into usage profiles (low, moderate, excessive) and to examine associations with age, gender, socioeconomic status, sleep, physical activity, well-being, self-regulation, and academic motivation.
Measured: From enrollment to the end of treatment at 4 weeks
Secondary outcomes (8)
Self-Reported Screen Use (Questionnaire Score)
Participants will self-report their perceived daily screen time and frequency of use across app categories. Questionnaire responses will be used to compare subjective and objective measures of screen use and to explore potential biases in self-estimation.
Measured: 1 day
Sleep Quality (Self-Reported Index)
Participants will complete a self-reported measure of sleep quality, including sleep duration, bedtime regularity, and perceived sleep disturbances. This outcome will be explored in relation to objective nighttime digital activity and mood variables.
Measured: 7 days
Physical Activity and Sedentary Behavior (Self-Reported Levels)
Participants will report their weekly physical activity, sitting time, and sedentary behaviors using standardized self-report questionnaires. These variables will be examined as predictors or correlates of screen-use profiles.
Measured: 7 days
Well-Being (Self-Reported Score)
Participants will complete a validated well-being questionnaire assessing positive mental health, life satisfaction, and emotional balance. Scores will be compared across screen-use profiles and related to objective digital behaviors.
Measured: 1 day
Anxiety (Self-Reported Symptom Score)
Anxiety symptoms will be assessed using a standard validated questionnaire. This outcome will be used to examine associations with objective digital behaviors.
Measured: 1 day
Depressive Symptoms (Self-Reported Score)
Participants will complete a validated depression questionnaire. Scores will be examined in relation to objective smartphone use indicators and will support analyses of risk factors for problematic digital use.
Measured: 1 day
Self-Regulation Capacity (Self-Reported Score)
Self-regulation will be assessed using a validated questionnaire measuring planning, inhibition, and control. This measure will help characterize screen-use profiles and explore cognitive factors associated with excessive use.
Measured: 1 day
Academic Motivation (Self-Reported Score)
Participants will complete a validated measure of academic motivation covering intrinsic, identified, introjected, and external regulation. Motivation scores will be analyzed across usage profiles to investigate potential conative differences between groups.
Measured: 1 day
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 Dec 2025
- Study start1 Apr 2022
- Primary completion1 Mar 2023
- Study completion1 Mar 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Screen TimeStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Cross-sectional
- Enrolment
- 171 participants (actual)
- Target duration
- 1 Month
Sponsor and investigators
- Lead sponsor
- Phonix Health
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07293208
- Sponsor's protocol ID
- PHX_OBS_CERGA_2022
- Acronym
- PHX_2022_1
- Status last verified
- Dec 2025
- First submitted
- 6 Dec 2025
- Last updated
- 19 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 19 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Characterization of Smartphone User Profiles (Caractérisation de Profils d'Utilisateurs de Smartphone)
- ClinicalTrials.gov ID
- NCT07293208
- Acronym / sponsor ID
- PHX_2022_1 / PHX_OBS_CERGA_2022
- Conditions
- Screen Time
- Keywords
- smartphone, problematic digital use, depression, academic motivation, young adult, adolescent, digital phenotyping
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 171 participants (actual)
- Lead sponsor
- Phonix HealthIndustry (pharma, biotech, devices)
- Study start
- 1 Apr 2022 (actual)
- Primary completion
- 1 Mar 2023 (actual)
- Study completion
- 1 Mar 2023 (actual)
- First posted
- 19 Dec 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this observational study is to describe how adolescents and young adults use screens in their daily lives and to identify different profiles of screen use ranging from low to excessive. The study also aims to understand how screen-use behaviors relate to health, motivation, and sociodemographic factors.
The main questions it aims to answer are:
What are the objective and self-reported patterns of screen use (e.g., frequency of use, types of apps, daily time spent, usage periods)?
Do distinct screen-use profiles emerge (low, moderate, intensive/excessive) when taking into account:
Age, gender, educational track (general, technological, vocational), Parents' socioeconomic status, Health variables (sleep quality, physical activity/sedentary behavior, well-being), Cognitive and conative variables (self-regulation capacity, academic motivation)? Are excessive users characterized by specific patterns, such as intensive use of social media, video platforms, or video games combined with mood problems, sleep difficulties, or motivational issues? Do screen-use profiles vary depending on age group (middle school, high school, university) and gender?
Are there mediating mechanisms explaining excessive use? Specifically:
Does poor self-regulation mediate the link between screen-use intensity and well-being? Do sleep problems mediate the link between excessive nighttime use and mood disturbances (anxiety, depression)? Do academic motivation and cognitive factors mediate differences between moderate and excessive users? If groups differ, researchers will compare low-use, moderate-use, and excessive-use profiles to determine whether they show meaningful differences in health, motivation, and sociodemographic characteristics.
Participants will:
Install a smartphone application that passively records daily screen-use indicators (e.g., usage time, app categories, frequency of openings, time windows of use).
Complete questionnaires assessing:
Self-reported screen use, Sleep, physical activity, well-being, Mood variables (anxiety, depression), Self-regulation, Academic motivation, Sociodemographic factors (age, gender, parents' SES, educational track).
Study design
- Observational model
- Cohort
- Time perspective
- Cross-sectional
- Target follow-up
- 1 Month
Who may qualify
- Ages
- 12 to 25 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult
- Study population
- Participants were recruited from secondary schools and universities in Grenoble, France, through institutional communication channels and digital platforms. Recruitment occurred within educational settings located in various regions, allowing inclusion of adolescents and young adults enrolled in middle school, high school, or university programs.
Key inclusion criteria (4 listed)
- Own an Android smartphone
- Have at least 200 MB of storage on your smartphone
- Be in middle school, high school, or university
- Be enrolled in a school within the Grenoble academy district
Key exclusion criteria (3 listed)
- Own an iPhone
- Participate in an interventional study in the field within the last six months
- Not sign the consent form
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| PhonixDiag Smartphone Monitoring ToolAlso: PhonixDiag AppPhonixDiag is a passive smartphone-based monitoring tool designed to collect objective digital behavior indicators in real time. The tool runs in the background of the participant's smartphone and records daily screen-use patterns, including frequency of app openings, time spent on recreational applications, usage periods throughout the day, and nighttime phone activity. PhonixDiag does not modify the participant's phone use or deliver any behavioral intervention. It functions solely as a data collection system to objectively assess screen-use behaviors and identify usage profiles (low, moderate, excessive). The tool is distinct from other digital interventions because it does not provide feedback, warnings, or recommendations, and operates exclusively for passive monitoring purposes. | Device | – |
Primary outcome
Objective Screen Use Time (Daily Median Over Monitoring Period)
Time frame: From enrollment to the end of treatment at 4 weeks
Objective screen-use time will be measured using the PhonixDiag smartphone monitoring tool. The outcome corresponds to the median daily duration (in minutes) spent on smartphone applications across the full monitoring period. This includes all app categories and reflects real-world behavioral engagement with digital media. The measure will be used to classify participants into usage profiles (low, moderate, excessive) and to examine associations with age, gender, socioeconomic status, sleep, physical activity, well-being, self-regulation, and academic motivation.
8 secondary outcomes
Self-Reported Screen Use (Questionnaire Score)
Time frame: 1 day
Sleep Quality (Self-Reported Index)
Time frame: 7 days
Physical Activity and Sedentary Behavior (Self-Reported Levels)
Time frame: 7 days
Well-Being (Self-Reported Score)
Time frame: 1 day
Anxiety (Self-Reported Symptom Score)
Time frame: 1 day
Depressive Symptoms (Self-Reported Score)
Time frame: 1 day
Self-Regulation Capacity (Self-Reported Score)
Time frame: 1 day
Academic Motivation (Self-Reported Score)
Time frame: 1 day
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 19 Dec 2025.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Screen Time, run by Phonix Health at 1 site in France.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 19 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in France. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Objective Screen Use Time (Daily Median Over Monitoring Period) (time frame: From enrollment to the end of treatment at 4 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 19 Dec 2025.