Just-in-Time Coping Prompts for Reactive Digital Behavior in College Students (REACT)

REACT: A Just-in-Time Adaptive Intervention to Reduce Reactive Digital Behavior in College Students

This study looks at the moments when college students feel a strong emotional swing, and how those moments relate to reacting online when upset, drinking alcohol, and eating in response to emotions. Participants wear a wrist device and answer brief check-ins on their phone several times a day for about five weeks. During part of that time, a study app sometimes sends a short coping message at moments when the wrist device and check-ins suggest emotions are shifting quickly. Whether a message is sent at any given moment is decided at random, and the study compares what participants do in the short window afterward. The study is a pilot designed to test whether the approach is feasible and to estimate how large its effects are.

Study Overview

• Status: Not yet recruiting
• Conditions: Aggression; Emotional Regulation; Alcohol Drinking in College; Emotional Eating
• Intervention / Treatment: Behavioral: Momentary coping prompt; Behavioral: Active control message

Detailed Description

REACT is a five-week micro-randomized trial in University of Florida students age 18 and older. Participants complete a baseline battery, wear a Garmin Venu 3, and respond to five to six smartphone check-ins per day. Week one is a no-prompt run-in that establishes each participant's own baseline distribution of momentary affective variability, indexed by the mean square of successive differences on consecutive affect ratings. From week two through week five, the app evaluates up to six decision points per day. A decision point is flagged when the participant's current variability exceeds their own 80th percentile threshold, computed within person rather than against a group average. At each available decision point the app randomizes with probability 0.5 whether to deliver a brief coping message, and if so selects a message type from those eligible in that context. Availability rules exclude sleep, stale device data, a 60-minute cooldown, a daily cap, and any safety override. Proximal outcomes are drawn from the first check-in within two hours after the decision point. Analysis uses weighted and centered least squares to estimate causal excursion effects, with pre-specified moderators.

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Yonghwan Chang, PhD; Phone Number: 352-294-1664; Email: yhchang@ufl.edu

Study Locations

• United States
  • Florida
    • Gainesville, Florida, United States, 32611
      • University of Florida
      • Contact: Yonghwan Chang, PhD; Phone Number: 352-294-1664; Email: yhchang@ufl.edu
      • Principal Investigator: Yonghwan Chang, PhD

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Currently enrolled University of Florida student
• Age 18 years or older
• Owns a smartphone used daily
• Willing to wear a wrist-worn device and complete brief check-ins several times daily for approximately five weeks

Exclusion Criteria:

• Varsity student-athlete governed by the university athletic association
• Unable to complete study procedures in English

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Coping prompt delivered; Decision points at which the randomization outcome is to deliver a brief cognitive-behavioral or acceptance-based coping message. Message type is selected at random from those eligible in the participant's current context. Every participant contributes decision points to this condition.	Behavioral: Momentary coping prompt; A single short message of one to three sentences delivered to the participant's smartphone at a randomized decision point, taking roughly fifteen to thirty seconds to read. Messages apply cognitive-behavioral techniques including thought records, perspective-taking, decatastrophizing, cost-benefit checks, implementation intentions, and behavioral redirection, or acceptance-based techniques including cognitive defusion, acceptance, values anchoring, urge surfing, and present-moment grounding. Delivery is capped at four messages per day with a minimum sixty-minute interval and is confined to participant-set waking hours. Messages may be dismissed without responding.
Active Comparator: No coping prompt or active control message; Decision points at which the randomization outcome is not to deliver a coping message. A brief neutral, non-directive acknowledgment message may be delivered as an active control so that receiving any message can be separated from receiving a coping message. Every participant contributes decision points to this condition.	Behavioral: Active control message; A brief neutral acknowledgment message matched to the coping messages on delivery mechanism and approximate length, containing no coping technique or behavioral suggestion.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Momentary urge to post or reply reactively, score on a 7-point scale.	Self-reported urge to post or reply about something upsetting, rated 1 to 7 at the first check-in within two hours after a randomized decision point. Higher scores indicate greater urge. Analyzed as a causal excursion effect comparing decision points at which a coping message was delivered with those at which it was not.	Within 2 hours after each randomized decision point, across weeks 2 to 5.
Momentary urge to drink alcohol, score on a 7-point scale.	Self-reported current urge to drink alcohol, rated 1 to 7 at the first check-in within two hours after a randomized decision point. Higher scores indicate greater urge. Analyzed as a causal excursion effect.	Within 2 hours after each randomized decision point, across weeks 2 to 5.
Momentary emotional influence on eating, score on a 7-point scale.	Self-reported rating of how much emotions influenced eating since the previous check-in, rated 1 to 7 at the first check-in within two hours after a randomized decision point. Analyzed as a causal excursion effect.	Within 2 hours after each randomized decision point, across weeks 2 to 5.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of delivered prompts receiving a response	Number of prompts receiving a rating response divided by number of prompts delivered. Pre-registered benchmark is 60 percent.	Through study completion, approximately 5 weeks per participant.
Proportion of enrolled participants retained to study end.	Number of participants completing the study divided by number enrolled. Pre-registered benchmark is 85 percent.	Through study completion, approximately 5 weeks per participant.
Momentary reactive online behavior since the previous check-in, self-reported occurrence	Self-reported occurrence of posting or replying while upset since the previous check-in, reported yes or no at the first check-in within two hours after a randomized decision point.	Within 2 hours after each randomized decision point, across weeks 2 to 5.
Number of standard drinks consumed since the previous check-in, self-reported count	Self-reported number of standard drinks consumed since the previous check-in.	Within 2 hours after each randomized decision point, across weeks 2 to 5.
Loss-of-control eating rating, score on a 7-point scale	Self-reported sense of losing control while eating since the previous check-in, rated 1 to 7.	Within 2 hours after each randomized decision point, across weeks 2 to 5
Proportion of scheduled check-ins completed	Number of completed check-ins divided by number of scheduled check-ins. Pre-registered feasibility benchmark is 75 percent.	Through study completion, approximately 5 weeks per participant.
Proportion of waking hours with valid wearable data	Hours of valid physiological data divided by estimated waking hours. Pre-registered benchmark is 80 percent.	Through study completion, approximately 5 weeks per participant.
Prompt helpfulness rating, score on a 7-point scale	Participant rating of how helpful the coping prompts were, rated 1 to 7.	Week 3 and end of study, approximately week 5.
System Usability Scale total score.	System Usability Scale (Brooke, 1996) total score, range 0 to 100, higher scores indicating better usability.	End of study, approximately week 5.

Collaborators and Investigators

• Sponsor: University of Florida
• Investigators: Principal Investigator: Yonghwan Chang, PhD, University of Florida

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): May 1, 2027
• Study Completion (Estimated): August 1, 2027

Study Registration Dates

• First Submitted: August 23, 2026
• First Submitted That Met QC Criteria: August 24, 2026
• First Posted (Actual): August 27, 2026

Study Record Updates

• Last Update Posted (Actual): August 27, 2026
• Last Update Submitted That Met QC Criteria: August 24, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Keywords: college students; ecological momentary assessment; just-in-time adaptive intervention; wearable sensor; micro-randomized trial; emotional volatility
• Additional Relevant MeSH Terms: Aberrant Motor Behavior in Dementia; Behavioral Symptoms; Drinking Behavior; Alcohol Drinking; Behavior; Feeding Behavior; Social Behavior; Self-Control; Alcohol Drinking in College; Aggression; Emotional Regulation; Emotional Eating
• Other Study ID Numbers: IRB202600940; 00135244 (Other Grant/Funding Number: University of Florida Research Opportunity Seed Fund)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared outside the research team. This is a pilot study collecting sensitive behavioral and biological data from a small identifiable campus population, and the informed consent does not provide for external sharing of individual-level data. Aggregate results will be published.

Drug and device information, study documents

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