Vibe Up Precision: A Trial Examining Whether Smartphone-Based Digital Markers Can Be Used To Personalise Smartphone-Based Digital Mental Health Interventions for University Students Experiencing Elevated Psychological Distress

GENERAL DESIGN This is a 4-arm randomised controlled trial of 8 weeks duration designed to assess whether digital phenotyping markers are associated with response to brief smartphone-delivered interventions for psychological distress among university students in Australia. Ethical approval for this trial was obtained under a Master Protocol of three methodologically similar trials. This trial registration pertains to 'Trial 1' under this Master Protocol, which will recruit Australian University students. All intervention content is delivered via a custom-built smartphone-based tool called MindGRID, which monitors the type and timing of intervention content delivered to the participant. The participant-facing intervention content is accessed by participants via the app store though a trial-specific instance of the MindGRID tool called the 'Vibe Up 2.0' app. Each participant will undergo an initial 2-week pre-intervention period involving twice-daily Ecological Momentary Assessment (EMA; Weeks 1 and 2). Next, participants will be randomly assigned to one of four trial arms (mindfulness, physical activity, sleep hygiene, control) that involve receiving access to their assigned intervention (or control), delivered in a modular manner, over a period of 2 weeks (Weeks 3 and Week 4). Once all intervention modules are released and the 2-week intervention period is complete, participants are provided with continued access to their assigned intervention (or control) for them to continue to review over a 4-week follow-up period (Weeks 5 to 8). Specific details about the pre-intervention EMA and the interventions used in the four trial arms during the intervention period are provided below. PRE-INTERVENTION EMA During the 2-week pre-intervention EMA period, all participants will complete EMA twice per day, with each EMA survey expected to take approximately 5 minutes to complete. The EMA will run on a signal-contingent protocol consisting of two daily random prompts to the participant generated by a custom-built smartphone application at a random time within two windows: morning (08:00-10:00) and evening (19:00-21:00). Participants will have up to 60 minutes to respond to the prompt, with a reminder sent after 30 minutes if the prompt has not been responded to. The EMA questionnaire was designed to provide a comprehensive assessment of anhedonia dynamics, with a particular emphasis on the need to distinguish between the multiple types of anhedonia that exist and the context behind them. To this end, each EMA measurement will consist of: • An initial question assessing the extent of positive affect that is present at the time. • Questions designed to elicit the existence of consummatory (i.e., present) anhedonia. - Social consummatory anhedonia and behavioural (activity-based) consummatory anhedonia will be assessed through separate questions. - If participants indicate that they are socialising or engaging in an activity, they will be asked whether they are enjoying these activities, how they would usually enjoy them, and how effortful they feel. - If participants indicate they are not socialising or engaging in an activity, then instead their levels of behavioural and social amotivation will be assessed instead. • If the EMA is taking place in the evening, further questions will be asked to determine the participant’s level of anticipatory anhedonia: - Similar to consummatory anhedonia, both social anticipatory anhedonia and behavioural anticipatory anhedonia will be assessed through separate questions. - Again, if participants indicate that they will be socialising or engaging in an activity, they will be asked whether they are looking forward to these events (anticipatory reward), how motivated they feel to engage in the activity, and how effortful they believe these events will feel. • A series of open-ended questions that are intended to provide context to the responses above. - Participants will be asked about what they are doing, and how aspects of this might be considered enjoyable or disappointing, - If the EMA is being completed in the evening, participants will also be asked how worthwhile/meaningful events that happened in their day was, and what plans they had for tomorrow. - Participants will be allowed to provide their answers in free text form or via voice recordings. INTERVENTION PERIOD At the end of Week 2, participants will be randomised to receive one of three interventions or a control for 2 weeks. These interventions consist of: a) Brief self-guided smartphone-delivered mindfulness (active intervention) b) Brief self-guided smartphone-delivered physical activity (active intervention) c) Brief self-guided smartphone-delivered sleep hygiene (active intervention) d) Brief self-guided smartphone-delivered EMA (control) Each intervention is entirely separate but consists of a combination of brief modular information covering key concepts, delivered via infographics, as well as structured activities (e.g., practicing mindfulness using a guided audio). All three active interventions as well as the EMA control have been used recently in the Vibe Up AI-Enhanced Adaptive Trial (trial ID ACTRN12621001223820) and the Vibe Up Precision Pilot Trial (trial ID: ACTRN12625000940471). A summary of the content for each is as follows: ARM 1: MINDFULNESS The Mindfulness intervention starts with an introductory module (3 minute video), followed by five guided mindfulness modules delivered as audio recordings (3-5 minutes in length). The content of the modules is as follows: a) Introductory video: Explains what mindfulness is and the benefits; defines formal vs. informal mindfulness practice; how to tune into the five senses and bring mindful awareness to daily activities; and how to reduce judgment and increase self-compassion. b) Module 1: Guided mindfulness practice based on mindful awareness of breathing (audio with male/female voice options) c) Module 2: Guided mindfulness practice teaching non-judgment towards thoughts, using 'leaves on a stream' imagery (audio with male/female voice options) d) Module 3: Guided mindfulness practice based on mindful awareness of body sensations and releasing of muscle tension (audio with male/female voice options) e) Module 4: Guided mindfulness practice encouraging the use of all five senses to bring curiosity to everyday activities (audio with male/female voice options) f) Module 5: Guided mindfulness practice blending awareness of surrounding environment and bodily sensations (audio with male/female voice options) The modules are made available to participants as follows: • The introductory video is available to participants immediately after randomisation to the intervention. • The first mindfulness audio recording becomes available immediately after the introductory video has been completed. • The subsequent mindfulness audio recordings are sequentially released, at one-day intervals (regardless of participant engagement). Expected effort: A minimum of one mindfulness audio recording completed daily at participants' convenience. Participantd are encouraged to complete all modules at least once by the end of the 2-week intervention period. Participants are also encouraged to practice bringing mindful awareness to activities throughout their day (‘informal’ mindfulness). ARM 2: PHYSICAL ACTIVITY The Physical Activity intervention starts with an introductory infographic explaining the benefits of physical activity for cognition, mental health and physical health, Australian guidelines for physical activity, how to set realistic goals and benefits of even small change, and tips to foster enjoyment of physical activity (e.g., being social, settings goals, tracking progress). It then prompts participants each day to choose a goal to increase their physical activity that day. An evidence-based 7-minute high-intensity circuit training (HICT) protocol, demonstrated via video, is provided as one option for increasing physical activity. Other examples of exercises that are suggested within the intervention are walking, social sport, gardening, yoga, bike riding or dancing. The modules are made available to participants as follows: • An introductory module containing infographic-based psychoeducation about the benefits of physical activity is available to participants immediately after randomisation to the intervention (< 5 min to read). • The Daily goal setting (2-3 minutes) and 7-minute HICT video becomes available immediately after a participant has completed the introductory module. Expected effort: Participants are encouraged to do some form of physical activity (eg, up to 30 mins) on most days throughout the two-week intervention period, with the 7-minute HICT work out offered as one option of ways they can include more physical activity in their day, or alternatively, increasing steps by 10% weekly. ARM 3: SLEEP HYGIENE The Sleep Hygiene intervention centres around four brief, sequential modules covering key sleep hygiene concepts, which are delivered via infographics. Each module takes up to five minutes to read. The content of the modules is as follows: a) Module 1: Why we sleep? Covers the recommended hours of sleep per night, the impact of lack of sleep on cognition and emotion, benefits of sleep for mental health and physical health, and an introduction to sleep hygiene. b) Module 2: Sleep habits. covers establishment of regular bedtime and wake time, eliminating or limiting naps, establishing a wind down routine. c) Module 3: Sleep environment. Covers how to reduce light, noise and temperature disturbance, and ensuring bedding is comfortable; limiting the use of bed to sleep and sex; the impact of electronic devices on sleep; get out of bed when unable to sleep for 20 minutes or more. d) Module 4: Reducing caffeine, alcohol and nicotine intake close to bedtime; eating a healthy diet; increasing physical activity and avoiding exercise close to bedtime. The modules are made available to participants as follows: • Module 1 is available to participants immediately after randomisation to the intervention. • Module 2 becomes available immediately after a participant has completed Module 1. • Module 3 becomes available two days after Module 2 is made available (regardless of participant engagement). • Module 4 becomes available two days after Module 3 is made available (regardless of participant engagement). Expected effort: All modules completed at least once by the end of the intervention period. Participants are instructed to choose one strategy from each of Module 2 – 4 and implement it daily (total of 3 strategies by end of intervention period). There is no recommended minimum time participants must practice sleep hygiene skills but it is anticipated that implementing the skills will take 10-30 minutes per day. ASSESSMENT OF ADHERENCE Throughout the intervention period, participants are asked to log their engagement with the intervention daily via an in-app logging question. For those assigned to the physical activity intervention, they are asked to log how many minutes of physical activity they engaged in that day; for those assigned to the sleep hygiene intervention, they are asked to log how many minutes they spent practicing sleep hygiene skills that day; and for those assigned to the mindfulness intervention, they are asked to log how many minutes of mindfulness practice they engaged in that day. Each log is expected to take less than 5 mins to complete. FOLLOW-UP PERIOD All participants will continue to have access to their assigned intervention throughout a 4-week follow-up period (Weeks 5 to 8). At the beginning of this 4-week follow-up period, they are encouraged, via instructional screens within the smartphone app, to practice implementing the skills learned in the intervention. No minimum level of effort or engagement is specified for the follow-up period.