Effects of Community-Based Caring Contact in Reducing Thwarted Belongingness Among Postdischarge Young Adults With Self-Harm: Randomized Controlled Trial

Background For patients with self-harm behaviors, the urge to hurt themselves persists after hospital discharge, leading to costly readmissions and even death. Hence, postdischarge intervention programs that reduce self-harm behavior among patients should be part of a cogent community mental health care policy. Objective We aimed to determine whether a combination of a self-help mobile app and volunteer support could complement treatment as usual (TAU) to reduce the risk of suicide among these patients. Methods We conducted a pragmatic randomized controlled trial on discharged patients aged between 18 and 45 years with self-harm episodes/suicide attempts, all of whom were recruited from 4 hospital emergency departments in Hong Kong. Participants were randomly assigned to one of three groups: (1) mobile app + TAU (“apps”), (2) mobile app + volunteer support + TAU (“volunteers”), or (3) TAU only as the control group (“TAU”). They were asked to submit a mobile app–based questionnaire during 4 measurement time points at monthly intervals. Results A total of 40 participants were recruited. Blending volunteer care with a preprogrammed mobile app was found to be effective in improving service compliance. Drawing upon the interpersonal-psychological theory of suicide, our findings suggested that a reduction in perceived burdensomeness and thwarted belongingness through community-based caring contact are linked to improvement in hopelessness, albeit a transient one, and suicide risk. Conclusions A combination of volunteer care with a self-help mobile app as a strategy for strengthening the continuity of care can be cautiously implemented for discharged patients at risk of self-harm during the transition from the hospital to a community setting. Trial Registration ClinicalTrials.gov NCT03081078; https://clinicaltrials.gov/study/NCT03081078

Is this a full powered effectiveness trial or a pilot/feasibility trial? * Manuscript tracking number * If this is a JMIR submission, please provide the manuscript tracking number under "other" (The ms tracking number can be found in the submission acknowledgement email, or when you login as author in JMIR. If the paper is already published in JMIR, then the ms tracking number is the four-digit number at the end of the DOI, to be found at the bottom of each published article in JMIR) TITLE AND ABSTRACT 1a) TITLE: Identification as a randomized trial in the title yes Other: subitem not at all important 1 2 3 4 5 essential 1a) Does your paper address CONSORT item 1a? * I.e does the title contain the phrase "Randomized Controlled Trial"? (if not, explain the reason under "other") 1a-i) Identify the mode of delivery in the title Identify the mode of delivery. Preferably use "web-based" and/or "mobile" and/or "electronic game" in the title. Avoid ambiguous terms like "online", "virtual", "interactive". Use "Internet-based" only if Intervention includes non-web-based Internet components (e.g. email), use "computer-based" or "electronic" only if o ine products are used. Use "virtual" only in the context of "virtual reality" (3-D worlds). Use "online" only in the context of "online support groups". Complement or substitute product names with broader terms for the class of products (such as "mobile" or "smart phone" instead of "iphone"), especially if the application runs on different platforms. Does your paper address subitem 1a-i? * Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study We used "community-based caring contact" to encapsulate all the modes of delivery across three arms (i.e., app only, app + volunteer and control group). Since we had an intervention group consisting potential physical volunteers contact upon participants' request, we did not include "mobile" to avoid confusion.

1a-ii) Non-web-based components or important co-interventions in title
Mention non-web-based components or important co-interventions in title, if any (e.g., "with telephone support").
C l e a r s e l e c t i o n Does your paper address subitem 1a-ii?
Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study For the intervention group that consisted potential physical volunteers contact, it would only happen if participants built rapport with the volunteers, which might resulted in a physical meet up. This component is optional. 1a-iii) Primary condition or target group in the title Mention primary condition or target group in the title, if any (e.g., "for children with Type I Diabetes") Example: A Web-based and Mobile Intervention with Telephone Support for Children with Type I Diabetes: Randomized Controlled Trial C l e a r s e l e c t i o n Does your paper address subitem 1a-iii? * Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "postdischarge young adults with self-harm" 08/11/2022, 12:42 CONSORT-EHEALTH (V 1.6.1) - subitem not at all important Does your paper address subitem 1b-i? * Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study 'We conducted a pragmatic RCT on discharged patients aged 18-45 with self-harm episodes/suicide attempts who were physically recruited from the emergency departments of four hospitals in Hong Kong. Participants were randomly assigned to one of three groups, "1) mobile app+TAU(App+TAU), 2) mobile app+volunteer support + TAU(App+Vol+TAU), or 3) TAU-only as the control group(TAU), for a three-month observation with four measurement time points' through self-assessed online questionnaires built in the mobile app.
https://docs.google.com/forms/d/e/1FAIpQLSfZBSUp1bwOc_OimqcS64RdfIAFvmrTSkZQL2-3O8O9hrL5Sw/viewform?hl=en_US… 12/75 subitem not at all important 1 2 3 4 5 essential 1b-ii) Level of human involvement in the METHODS section of the ABSTRACT Clarify the level of human involvement in the abstract, e.g., use phrases like "fully automated" vs. "therapist/nurse/care provider/physician-assisted" (mention number and expertise of providers involved, if any). (Note: Only report in the abstract what the main paper is reporting. If this information is missing from the main body of text, consider adding it) C l e a r s e l e c t i o n Does your paper address subitem 1b-ii?
Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study 'We conducted a pragmatic RCT on discharged patients aged 18-45 with self-harm episodes/suicide attempts who were physically recruited from the emergency departments of four hospitals in Hong Kong. Participants were randomly assigned to one of three groups, 1) mobile app+TAU(App+TAU), 2) mobile app+"volunteer" support + TAU(App+Vol+TAU), or 3) TAU-only as the control group(TAU), for a three-month observation with four measurement time points' through self-assessed online questionnaires built in the mobile app. Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "We conducted a pragmatic RCT on discharged patients aged 18-45 with self-harm episodes/suicide attempts "who were physically recruited from the emergency departments of four hospitals in Hong Kong". Participants were randomly assigned to one of three groups, 1) mobile app+TAU(App+TAU), 2) mobile app+volunteer support + TAU(App+Vol+TAU), or 3) TAU-only as the control group(TAU), "for a three-month observation with four measurement time points through self-assessed online questionnaires built in the mobile app". Does your paper address subitem 1b-iv?
Copy and paste relevant sections from the manuscript abstract (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "A total of 40 participants were recruited. Blending volunteer care with a preprogrammed mobile app was found effective in improving service compliance. Drawing upon the interpersonal-psychological theory of suicide (IPTS), our findings could ascertain a reduction in thwarted belongingness (TB) through community-based caring contact is linked to improvement in hopelessness, albeit a transient one, and suicide risk in a growth model."  Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The aims of the study reported herein were to determine whether community-based caring contact via a mobile app with or without volunteer support, in addition to TAU (psychiatric and psychosocial treatments), is effective in reducing the suicide risk among post-discharge self-harm young adults and to generate empirical evidence on the use of these interventions as an engagement tool to support this high-risk group, who often default on prescribed treatments. " Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The interpersonal-psychological theory of suicide (IPTS) provides a theoretical explanation, positing that social connectedness and assurance buffer against perceived loneliness and burdensomeness, which are closely related to hopelessness and suicidal behaviors (Joiner, 2005;Joiner et al., 2002;Van Orden et al., 2010, 2021. The theory suggests that thwarted belongingness (TB, "I am alone") and perceived burdensomeness (PB, "I am a burden") are two modifiable, and distinct but related, interpersonal constructs contributing to the formulation of suicide desire and subsequent suicide attempts and death, particularly when the two factors are perceived to be hopelessly unchanging and associated with an acquired capability for or means of suicide (Van Orden et al., 2010). The specific benefits that community-based interventions can bring in reducing suicide risks among individuals discharged from a clinical setting to the community are yet to be ascertained." subitem not at all important 1 2 3 4 5 essential 4a) Eligibility criteria for participants Does your paper address CONSORT subitem 3b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Age cutoff was extended to 45 years due to difficulty recruiting participants. Only one user was recruited this way and the impact to the overall study is minimal.

3b-i) Bug fixes, Downtimes, Content Changes
Bug xes, Downtimes, Content Changes: ehealth systems are often dynamic systems. A description of changes to methods therefore also includes important changes made on the intervention or comparator during the trial (e.g., major bug xes or changes in the functionality or content) (5-iii) and other "unexpected events" that may have in uenced study design such as staff changes, system failures/downtimes, etc. [2].
Does your paper address subitem 3b-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Your answer Does your paper address CONSORT subitem 4a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Your answer

4a-i) Computer / Internet literacy
Computer / Internet literacy is often an implicit "de facto" eligibility criterion -this should be explicitly clari ed.
C l e a r s e l e c t i o n Does your paper address subitem 4a-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Researcher also walked through the navigation of the mobile application with the participants and addressed all the questions that participants raised to ensure the level of computer / Internet literacy would not affect their ability to receive information/intervention via the mobile application. subitem not at all important 1 2 3 4 5 essential 4a-ii) Open vs. closed, web-based vs. face-to-face assessments: Open vs. closed, web-based vs. face-to-face assessments: Mention how participants were recruited (online vs. o ine), e.g., from an open access website or from a clinic, and clarify if this was a purely web-based trial, or there were face-to-face components (as part of the intervention or for assessment), i.e., to what degree got the study team to know the participant. In online-only trials, clarify if participants were quasi-anonymous and whether having multiple identities was possible or whether technical or logistical measures (e.g., cookies, email con rmation, phone calls) were used to detect/prevent these.
C l e a r s e l e c t i o n Does your paper address subitem 4a-ii? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Patients admitted to the emergency departments of the participating hospitals followed the usual medical protocols before being identified by a doctor or psychiatric nurse as potential participants who met both the inclusion and exclusion criteria. The research team then contacted those who met the criteria and explained the study to them in detail, including the randomization to different groups and ethical concerns, and obtained their written informed consent to participate in the study. After such consent was received, a 20-minute questionnaire was administered to participants during a face-to-face interview (T0). All participants were notified via a downloaded mobile app of the group to which they had been assigned and began receiving the corresponding intervention." 4b) Settings and locations where the data were collected 4a-iii) Information giving during recruitment Information given during recruitment. Specify how participants were briefed for recruitment and in the informed consent procedures (e.g., publish the informed consent documentation as appendix, see also item X26), as this information may have an effect on user self-selection, user expectation and may also bias results.
C l e a r s e l e c t i o n Does your paper address subitem 4a-iii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study The research team then physically met up with those who met the criteria at the hospital and explained the study to them in detail, including the randomization to different groups and ethical concerns, and obtained their written informed consent to participate in the study.
subitem not at all important 1 2 3 4 5 essential Does your paper address CONSORT subitem 4b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "All participants completed the questionnaire at T0 during a face-to-face interview with a research team member soon before or after hospital discharge". Remaining surveys were conducted after hospital discharge.

4b-i) Report if outcomes were (self-)assessed through online questionnaires
Clearly report if outcomes were (self-)assessed through online questionnaires (as common in web-based trials) or otherwise.
C l e a r s e l e c t i o n Does your paper address subitem 4b-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The expected outcomes were a reduction in suicidal ideation, hopelessness, TB, and PB total scores and an increase in compliance with professional help. Suicidal ideation was measured by the self-report Chinese version of the four-item short form of the Adult Suicidal Ideation Questionnaire (ASIQ4), which has been demonstrated to exhibit a modest level of sensitivity (64%) and superior specificity (76%), as well as a positive predictive value of 8.4% on non-fatal suicidality and suicide deaths at the cut-off of 1 (Fu et al., 2007). Hopelessness was measured by the self-report 4-item short form (BHS4) of the Beck Hopelessness Scale (BHS; Beck et al., 1974), which was tested in a local panel survey (Yip and Cheung, 2006) based on the Chinese version developed by Shek (1993). The BHS4 is highly correlated (.88) with the BHS, and its AUC (95% CI) (0.70; 0.65-0.75) is as strong as that of the BHS in identifying people with suicidal ideation. The cut-off score of 11 for suicidal ideation provides 65.8% sensitivity and 67.3% specificity (Yip and Cheung, 2006). TB and PB were assessed by the Interpersonal Needs Questionnaire (INQ), a 15-item measure of beliefs about whether one's need to belong is met or unmet and self-perceptions of being a burden to others. Each item is rated on a 7-point Likert scale, with higher scores indicating higher levels of TB and PB (Van Orden et al., 2012). Self-reported compliance with prescribed treatment (frequency) in relation to the index self-harm episode, including psychiatric followup care (e.g., medication, out-patient follow-up treatment, and community psychiatric nursing service) and psycho-social services (e.g., clinical psychology service, medical social work service), as well as obtaining informal help from families and friends, was measured by a self-developed service utilization checklist. Depressive state was treated as a covariate and measured by the Center for Epidemiological Studies Depression Scale (CESD; Cheung and Bagley, 1998). CESD scores measured by two factors, an affective and somatic symptom factor and an interpersonal problem factor that patients encountered in the past week, were controlled in growth models. " subitem not at all important 1 2 3 4 5 essential 5) The interventions for each group with sufficient details to allow replication, including how and when they were actually administered 4b-ii) Report how institutional affiliations are displayed Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study All four hospitals were run by the Hospital Authority.

5-ii) Describe the history/development process
Describe the history/development process of the application and previous formative evaluations (e.g., focus groups, usability testing), as these will have an impact on adoption/use rates and help with interpreting results.
C l e a r s e l e c t i o n

Does your paper address subitem 5-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Unit tests and usability testing were carried out before final app deployment.

5-iii) Revisions and updating
Revisions and updating. Clearly mention the date and/or version number of the application/intervention (and comparator, if applicable) evaluated, or describe whether the intervention underwent major changes during the evaluation process, or whether the development and/or content was "frozen" during the trial. Describe dynamic components such as news feeds or changing content which may have an impact on the replicability of the intervention (for unexpected events see item 3b).
C l e a r s e l e c t i o n Does your paper address subitem 5-iii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study App shows random positive messages of the day, scheduled appointment reminders, important phone numbers, survey question sets, plus other static content.
subitem not at all important 1 2 3 4 5 essential 5-iv) Quality assurance methods Provide information on quality assurance methods to ensure accuracy and quality of information provided [1], if applicable.
C l e a r s e l e c t i o n Does your paper address subitem 5-iv?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study The most up-to-date information is used to create the mental health information library. subitem not at all important 1 2 3 4 5 essential 5-v) Ensure replicability by publishing the source code, and/or providing screenshots/screen-capture video, and/or providing flowcharts of the algorithms used Ensure replicability by publishing the source code, and/or providing screenshots/screencapture video, and/or providing owcharts of the algorithms used. Replicability (i.e., other researchers should in principle be able to replicate the study) is a hallmark of scienti c reporting.
C l e a r s e l e c t i o n Does your paper address subitem 5-v?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study The software is a standard info-based app. No proprietary algorithm is used in the study.

5-vi) Digital preservation
Digital preservation: Provide the URL of the application, but as the intervention is likely to change or disappear over the course of the years; also make sure the intervention is archived (Internet Archive, webcitation.org, and/or publishing the source code or screenshots/videos alongside the article). As pages behind login screens cannot be archived, consider creating demo pages which are accessible without login.
C l e a r s e l e c t i o n Does your paper address subitem 5-vi?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study See App Store link above. Apple already took down the application.

5-vii) Access
Access: Describe how participants accessed the application, in what setting/context, if they had to pay (or were paid) or not, whether they had to be a member of speci c group. If known, describe how participants obtained "access to the platform and Internet" [1]. To ensure access for editors/reviewers/readers, consider to provide a "backdoor" login account or demo mode for reviewers/readers to explore the application (also important for archiving purposes, see vi).
C l e a r s e l e c t i o n Does your paper address subitem 5-vii? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Grocery gift coupons were offered as incentives for every questionnaire completed thereafter."

5-ix) Describe use parameters
Describe use parameters (e.g., intended "doses" and optimal timing for use). Clarify what instructions or recommendations were given to the user, e.g., regarding timing, frequency, heaviness of use, if any, or was the intervention used ad libitum.
C l e a r s e l e c t i o n Does your paper address subitem 5-ix?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study The surveys given during each timepoint asked users to self-report service use and helpseeking behavior.

5-x) Clarify the level of human involvement
Clarify the level of human involvement (care providers or health professionals, also technical assistance) in the e-intervention or as co-intervention (detail number and expertise of professionals involved, if any, as well as "type of assistance offered, the timing and frequency of the support, how it is initiated, and the medium by which the assistance is delivered". It may be necessary to distinguish between the level of human involvement required for the trial, and the level of human involvement required for a routine application outside of a RCT setting (discuss under item 21 -generalizability).
C l e a r s e l e c t i o n Does your paper address subitem 5-x?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study All three arms involve some degree of human involvement, i.e. doctors administrating TAU.
"For the intervention arm, volunteers aged 25 or above with at least a bachelor's degree were recruited and asked to attend six 3-hour training sessions on specific topics, including basic knowledge on suicide prevention, suicide risk screening skills, and empathetic communication skills. A similar intervention was examined in a pilot study and found to be effective in reducing depressive symptoms and hopelessness (Law et al., 2016). Volunteers who completed the training and met the assessment criteria were invited to take part in the study. They were then matched with cases allocated to the App+Vol+TAU group in pairs and asked to make the first contact with the patients concerned within 24 hours of the assignment. Volunteers' duties included initiating at least two contacts per week with the assigned patients, having at least one face-to-face meeting with them per month, conducting suicide risk screening, and sending supportive messages and reminders of follow-up treatment. They were also required to report back on the patients' progress and attend in-service training and supervision sessions ( Does your paper address subitem 5-xi? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The main components of the mobile app were positive quotes/messages displayed on the home page, a mental health information library, emergency information, including the number of a 24-hour suicide prevention hotline, a medical follow-up appointment reminder, a survey, a user feedback form, and, if applicable, volunteer support services (see Table 1)." Does your paper address subitem 5-xii? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study The app demo is carried out during a "face-to-face interview with a research team member soon before or after hospital discharge." Does your paper address CONSORT subitem 6a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The expected outcomes were a reduction in suicidal ideation, hopelessness, TB, and PB total scores and an increase in compliance with professional help. Suicidal ideation was measured by the self-report Chinese version of the four-item short form of the Adult Suicidal Ideation Questionnaire (ASIQ4), which has been demonstrated to exhibit a modest level of sensitivity (64%) and superior specificity (76%), as well as a positive predictive value of 8.4% on non-fatal suicidality and suicide deaths at the cut-off of 1 (Fu et al., 2007). Hopelessness was measured by the self-report 4-item short form (BHS4) , 2012). Self-reported compliance with prescribed treatment (frequency) in relation to the index self-harm episode, including psychiatric followup care (e.g., medication, out-patient follow-up treatment, and community psychiatric nursing service) and psycho-social services (e.g., clinical psychology service, medical social work service), as well as obtaining informal help from families and friends, was measured by a self-developed service utilization checklist. Depressive state was treated as a covariate and measured by the Center for Epidemiological Studies Depression Scale (CESD; Cheung and Bagley, 1998). CESD scores measured by two factors, an affective and somatic symptom factor and an interpersonal problem factor that patients encountered in the past week, were controlled in growth models. " subitem not at all important 1 2 3 4 5 essential 6b) Any changes to trial outcomes after the trial commenced, with reasons 6a-iii) Describe whether, how, and when qualitative feedback from participants was obtained Describe whether, how, and when qualitative feedback from participants was obtained (e.g., through emails, feedback forms, interviews, focus groups).
C l e a r s e l e c t i o n

Does your paper address subitem 6a-iii?
Copy and paste relevant sections from manuscript text Researchers also reached out to participants in T3 (i.e., post intervention period) via phone calls to obtain qualitative feedback (e.g., their thoughts on the content of the mobile application and ways to improve their overall experience with the intervention).
Does your paper address CONSORT subitem 6b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study No change to trial outcomes. Copy and paste relevant sections from manuscript title (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study " The a priori estimated sample size for each group was 36, with projected retention rates of 80%, 70%, and 60% at T1, T2, and T3, respectively, a two-sided significance level (α) of 0.05, and statistical power (1-β) of 0.8 (Lu et al., 2008)." 8a) Method used to generate the random allocation sequence NPT: When applicable, how care providers were allocated to each trial group 8b) Type of randomisation; details of any restriction (such as blocking and block size) Does your paper address CONSORT subitem 7b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Analysis was carried out at the end of the study period.
Does your paper address CONSORT subitem 8a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Pseudorandom generator was used to assign users to groups.
Does your paper address CONSORT subitem 8b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Participants were assigned to groups by simple random sampling." 9) Mechanism used to implement the random allocation sequence (such as sequentially numbered containers), describing any steps taken to conceal the sequence until interventions were assigned 10) Who generated the random allocation sequence, who enrolled participants, and who assigned participants to interventions 11a) If done, who was blinded after assignment to interventions (for example, participants, care providers, those assessing outcomes) and how NPT: Whether or not administering co-interventions were blinded to group assignment Does your paper address CONSORT subitem 9? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Screened and consented recruits were assigned an incremental participant id, each of which was pre-mapped to a group using a pseudorandom generator from a website.
Does your paper address CONSORT subitem 10? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study C.S. Lai, a co-author, managed the sequence allocation and enrollment. 11a-i) Specify who was blinded, and who wasn't 11a-Specify who was blinded, and who wasn't. Usually, in web-based trials it is not possible to blind the participants [1, 3] (this should be clearly acknowledged), but it may be possible to blind outcome assessors, those doing data analysis or those administering cointerventions (if any).
C l e a r s e l e c t i o n Does your paper address subitem 11a-i? 11a-* Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Participants will know if they belong to one of the three groups due to the way the experiment was set up. TAU component was blinded and was received by all participants. 11a-ii) Discuss e.g., whether participants knew which intervention was the 11a-"intervention of interest" and which one was the "comparator" Informed consent procedures (4a-ii) can create biases and certain expectations -discuss e.g., whether participants knew which intervention was the "intervention of interest" and which one was the "comparator".
C l e a r s e l e c t i o n Does your paper address subitem 11a-ii? 11a-Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study All participants were notified via a downloaded mobile app of the group to which they had been assigned and began receiving the corresponding intervention. It is crucial for participants to know which group they were assigned to because it would allow them to have reasonable expectations in this study, especially those in the control group, and know what interventions they could get access to (e.g., contacting volunteers). 12a) Statistical methods used to compare groups for primary and secondary outcomes NPT: When applicable, details of whether and how the clustering by care providers or centers was addressed Does your paper address CONSORT subitem 11b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "TAU was prescribed by the hospitals as per individual patients' medical conditions, which may include psychiatric out-patient follow-up, medication, and psychosocial interventions related to the index self-harm episode. " Does your paper address CONSORT subitem 12a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Chi-square tests (categorical variables) and t-tests (continuous variables) at a .05 level of significance (p < .05) were performed to detect differences in the distribution of the key variables, i.e., age, sex, hospital, and depressive state, among the three groups. Correlations among the measurements were also tested at T0 to verify their associations with one another at baseline." "A growth model with varying intercept and slope was fitted to capture both the fixed effects of averages across individuals and the random effects of individual deviations from those averages (Hesser, 2015). In standard frequentist regression, a small sample size with high degrees of sample variation and dropouts limits the degrees of freedom of data variance. To retain Eq.
(1), keeping as many predictors and covariates as possible, Bayesian inference with Hamiltonian Monte Carlo sampling was adopted in the analysis to account for (in-)group differences that might arise from the unequal allocation of participants in simple random sampling. " subitem not at all important 1 2 3 4 5 essential 12b) Methods for additional analyses, such as subgroup analyses and adjusted analyses 12a-i) Imputation techniques to deal with attrition / missing values Imputation techniques to deal with attrition / missing values: Not all participants will use the intervention/comparator as intended and attrition is typically high in ehealth trials. Specify how participants who did not use the application or dropped out from the trial were treated in the statistical analysis (a complete case analysis is strongly discouraged, and simple imputation techniques such as LOCF may also be problematic [4]).
C l e a r s e l e c t i o n Does your paper address subitem 12a-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "When a longitudinal study contains a considerable amount of missing data, Chakraborty and Gu (2009) recommend that ITT analysis be carried out using mixed-effect modeling without imputation to minimize the loss of statistical power. Because the growth model is also known as a linear mixed-effects model, ITT analysis would have been automatically conducted in tandem to minimize bias. "

X26) REB/IRB Approval and Ethical Considerations [recommended as subheading under "Methods"] (not a CONSORT item)
subitem not at all important 1 2 3 4 5 essential Does your paper address CONSORT subitem 12b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The actual choice of components that make up Xit was identified by principal component analysis. Subgroup attributes explaining less than 1% of the variance were dropped from the final specification to improve the model fit. All parameters were standardized before model fitting to speed up convergence. " Does your paper address subitem X26-i?

X26-i) Comment on ethics committee approval
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "With reference to ethical approval, we are bound to observe and comply with all applicable requirements under the Hospital Authority's standard operating procedure, the Declaration of Helsinki, and the ICH GCP (if applicable)"

x26-ii) Outline informed consent procedures
Outline informed consent procedures e.g., if consent was obtained o ine or online (how? Checkbox, etc.?), and what information was provided (see 4a-ii). See [6] for some items to be included in informed consent documents.
C l e a r s e l e c t i o n

Does your paper address subitem X26-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study The research team then physically met up with those who met the criteria at the hospital and explained the study to them in detail, including the randomization to different groups and ethical concerns, and obtained their written informed consent to participate in the study.

RESULTS
13a) For each group, the numbers of participants who were randomly assigned, received intended treatment, and were analysed for the primary outcome NPT: The number of care providers or centers performing the intervention in each group and the number of patients treated by each care provider in each center

X26-iii) Safety and security procedures
Safety and security procedures, incl. privacy considerations, and any steps taken to reduce the likelihood or detection of harm (e.g., education and training, availability of a hotline) C l e a r s e l e c t i o n

Does your paper address subitem X26-iii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study All cases received treatment as usual from the hospitals where they were admitted to. For those in the intervention group of Vol+APP, regular supervision was provided to volunteers who offered ongoing support to cases during the intervention period. Volunteers were trained to do basic screening of suicide ideation and self-harm.
13b) For each group, losses and exclusions after randomisation, together with reasons Does your paper address CONSORT subitem 13a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study This is already addressed by CONSORT flow diagram in Figure 1.
Does your paper address CONSORT subitem 13b? (NOTE: Preferably, this is shown in a CONSORT flow diagram) * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Does your paper address subitem 13b-i?
Copy and paste relevant sections from the manuscript or cite the gure number if applicable (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Results were self-reported, not monitored.
subitem not at all important 1 2 3 4 5 essential Does your paper address CONSORT subitem 14a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Participants, after providing informed written consent for participation, were randomly assigned to one of three groups, 1) mobile app + TAU (App+TAU), 2) mobile app + volunteer support + TAU (App+Vol+TAU), or 3) TAU-only as the control group (TAU), for a three-month observation with four measurement time points (T0 = baseline; T1 = one month; T2 = two months; T3 = three months after T0 (at post-intervention)."

14a-i) Indicate if critical "secular events" fell into the study period
Indicate if critical "secular events" fell into the study period, e.g., signi cant changes in Internet resources available or "changes in computer hardware or Internet delivery resources" C l e a r s e l e c t i o n Does your paper address subitem 14a-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Recruitment at the emergency departments was periodically suspended in 2019 owing to social unrest and in 2020 in the wake of the COVID-19 outbreak" 14b) Why the trial ended or was stopped (early)

15) A table showing baseline demographic and clinical characteristics for each
group NPT: When applicable, a description of care providers (case volume, quali cation, expertise, etc.) and centers (volume) in each group Does your paper address CONSORT subitem 14b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Recruitment at the emergency departments was periodically suspended in 2019 owing to social unrest and in 2020 in the wake of the COVID-19 outbreak" Does your paper address CONSORT subitem 15? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study See Tables 2 and 3  In ehealth trials it is particularly important to report demographics associated with digital divide issues, such as age, education, gender, social-economic status, computer/Internet/ehealth literacy of the participants, if known.
C l e a r s e l e c t i o n Does your paper address subitem 15-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The age range of 18-45 was considered appropriate in the local context because young adults in this group are likely to be receptive to an approach by volunteers and prone to using such communication modes as social media and smartphones (C&SD, 2022)" "The smartphone penetration rate in Hong Kong rose from 92.1% in 2020 to 92.9% in 2021 (C&SD, 2022), with the rise particularly notable during the COVID-19 pandemic. Mobile apps have become part of people's decision-making and problem-solving. For example, they have been widely used for information-sharing, risk assessment, training, and self-management during the pandemic (see Kondylakis et al., 2020). With such a wide reach and the ability to be offered at very low cost, digital support seems to be a viable auxiliary for individuals at risk of suicide when standardized medical follow-up care is made available as a necessary component. " subitem not at all important 1 2 3 4 5 essential 16-i) Report multiple "denominators" and provide definitions Report multiple "denominators" and provide de nitions: Report N's (and effect sizes) "across a range of study participation [and use] thresholds" [1], e.g., N exposed, N consented, N used more than x times, N used more than y weeks, N participants "used" the intervention/comparator at speci c pre-de ned time points of interest (in absolute and relative numbers per group). Always clearly de ne "use" of the intervention.
C l e a r s e l e c t i o n Does your paper address subitem 16-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Most of it is addressed in the CONSORT diagram and the descriptive stat tables. 17a) For each primary and secondary outcome, results for each group, and the estimated effect size and its precision (such as 95% confidence interval)

16-ii) Primary analysis should be intent-to-treat
Primary analysis should be intent-to-treat, secondary analyses could include comparing only "users", with the appropriate caveats that this is no longer a randomized sample (see 18-i).
C l e a r s e l e c t i o n Does your paper address subitem 16-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Because the growth model is also known as a linear mixed-effects model, ITT analysis would have been automatically conducted in tandem to minimize bias." Does your paper address CONSORT subitem 17a? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study See Table 4, and "The proportions of reported compliance with service treatment and the seeking of professional and informal help in the App+TAU and App+Vol+TAU groups were much higher in general than that in the TAU group. These observations were comparable with the results of the growth model after controlling for the level covariate, i.e., CESD, and unobserved latent groups. In particular, when all three intervention timepoints (T0, T1, and T2) were considered, the App+TAU intervention was able to reduce BHS4 scores more effectively than either TAU or App+Vol+TAU. The calculated mean effect size d was large at 1.15, reinforced by the fact that the App+TAU group had only 1.6% of ROPE overlapping with the 89% HDI region. There was a 98% chance that a reduction was observed in the App+TAU arm relative to TAU. As it may take some time for an intervention to take effect, it was more sensible to compare data between timepoints T0 and T2. After dropping T1 from the model, the region of overlap between App+TAU and BHS4 fell to 0.7%, whereas d increased to 1.33 and the posterior probability increased to 99%. Both the volunteer care and app interventions were also more effective in bringing down the overall INQ, at d 0.76 and d 0.60, respectively. Much of the change was due to a noticeable fall in TB scores in App+TAU and App+Vol+TAU relative to TAU, as indicated by d >= 0.47, a promising medium effect. A larger sample size would be needed to fully reject the null hypothesis, as 7.6% of ROPE at most overlapped with the credible interval. Despite having a small calculated effect size of 0.22, treatment by App+Vol+TAU has the potential to lower ASIQ4 scores over time. See Table 4 for the estimated standardized treatment effects and calculated mean effect sizes at timepoints T0 and T2. A larger sample size is needed to ascertain the mediation effects in the interventions, i.e., to verify the existence of causal pathway TB->BHS->ASIQ. " subitem not at all important 1 2 3 4 5 essential 17b) For binary outcomes, presentation of both absolute and relative effect sizes is recommended 17a-i) Presentation of process outcomes such as metrics of use and intensity of use In addition to primary/secondary (clinical) outcomes, the presentation of process outcomes such as metrics of use and intensity of use (dose, exposure) and their operational de nitions is critical. This does not only refer to metrics of attrition (13-b) (often a binary variable), but also to more continuous exposure metrics such as "average session length". These must be accompanied by a technical description how a metric like a "session" is de ned (e.g., timeout after idle time) [1] (report under item 6a).

Does your paper address subitem 17a-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Your answer 18) Results of any other analyses performed, including subgroup analyses and adjusted analyses, distinguishing pre-specified from exploratory Does your paper address CONSORT subitem 17b? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Primary outcomes are not binary.
Does your paper address CONSORT subitem 18? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The proportions of reported compliance with service treatment and the seeking of professional and informal help in the App+TAU and App+Vol+TAU groups were much higher in general than that in the TAU group. These observations were comparable with the results of the growth model after controlling for the level covariate, i.e., CESD, and unobserved latent groups. In particular, when all three intervention timepoints (T0, T1, and T2) were considered, the App+TAU intervention was able to reduce BHS4 scores more effectively than either TAU or App+Vol+TAU. The calculated mean effect size d was large at 1.15, reinforced by the fact that the App+TAU group had only 1.6% of ROPE overlapping with the 89% HDI region. There was a 98% chance that a reduction was observed in the App+TAU arm relative to TAU. As it may take some time for an intervention to take effect, it was more sensible to compare data between timepoints T0 and T2. After dropping T1 from the model, the region of overlap between App+TAU and BHS4 fell to 0.7%, whereas d increased to 1.33 and the posterior probability increased to 99%. Both the volunteer care and app interventions were also more effective in bringing down the overall INQ, at d 0.76 and d 0.60, respectively. Much of the change was due to a noticeable fall in TB scores in App+TAU and App+Vol+TAU relative to TAU, as indicated by d >= 0.47, a promising medium effect. A larger sample size would be needed to fully reject the null hypothesis, as 7.6% of ROPE at most overlapped with the credible interval. Despite having a small calculated effect size of 0.22, treatment by App+Vol+TAU has the potential to lower ASIQ4 scores over time. See Table 4 for the estimated standardized treatment effects and calculated mean effect sizes at timepoints T0 and T2. A larger sample size is needed to ascertain the mediation effects in the interventions, i.e., to verify the existence of causal pathway TB->BHS->ASIQ. "

18-i) Subgroup analysis of comparing only users
A subgroup analysis of comparing only users is not uncommon in ehealth trials, but if done, it must be stressed that this is a self-selected sample and no longer an unbiased sample from a randomized trial (see 16-iii).

Does your paper address subitem 18-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Your answer Does your paper address CONSORT subitem 19? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "Recruitment at the emergency departments was periodically suspended in 2019 owing to social unrest and in 2020 in the wake of the COVID-19 outbreak, which led to a small sample size with a higher number of participants in the TAU group and a high attrition rate of between 55% and 63% at T1. The overall attrition rate measured at the end of the intervention at T2 was 33.3-36.4%."

19-i) Include privacy breaches, technical problems
Include privacy breaches, technical problems. This does not only include physical "harm" to participants, but also incidents such as perceived or real privacy breaches [1], technical problems, and other unexpected/unintended incidents. "Unintended effects" also includes unintended positive effects [2].

Does your paper address subitem 19-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Your answer subitem not at all important 1 2 3 4 5 essential 22-i) Restate study questions and summarize the answers suggested by the data, starting with primary outcomes and process outcomes (use) Restate study questions and summarize the answers suggested by the data, starting with primary outcomes and process outcomes (use).
C l e a r s e l e c t i o n Does your paper address subitem 22-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "More evidence on the use of apps to treat people with mental health issues has emerged in recent years, but is not conclusive. For example, use of an app as part of clinical treatment for suicide prevention was unexpectedly found to exert negative effects on suicide risk reduction in an adult clinical sample with mild to moderate symptoms of anxiety, depression, and adjustment disorders (

Does your paper address subitem 22-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study

20-i) Typical limitations in ehealth trials
Typical limitations in ehealth trials: Participants in ehealth trials are rarely blinded. Ehealth trials often look at a multiplicity of outcomes, increasing risk for a Type I error. Discuss biases due to non-use of the intervention/usability issues, biases through informed consent procedures, unexpected events.
Does your paper address subitem 20-i? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "The social unrest in 2019 and COVID-19 pandemic from 2020 onwards took a heavy toll on this research study, particularly given that the sole recruitment sites were hospitals. Although we adopted several measures to increase the case admission rate, including briefings with medical staff, the multiple outbreaks of COVID-19 in 2020-2021 resulted in the full suspension of research at hospital sites. The study's sample size was thus suboptimal, limiting the external validity of its findings. The volunteer support intervention was also unexpectedly interrupted from time to time. Face-to-face contact was difficult to render during the aforementioned trying periods. Nevertheless, all of the volunteers involved in the study offered their unfailing support to the participants and exercised incredible patience and care. "

21-i) Generalizability to other populations
Generalizability to other populations: In particular, discuss generalizability to a general Internet population, outside of a RCT setting, and general patient population, including applicability of the study results for other organizations Does your paper address subitem 21-i?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Discuss if there were elements in the RCT that would be different in a routine application setting (e.g., prompts/reminders, more human involvement, training sessions or other cointerventions) and what impact the omission of these elements could have on use, adoption, or outcomes if the intervention is applied outside of a RCT setting.

Does your paper address subitem 21-ii?
Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study Your answer

X27) Conflicts of Interest (not a CONSORT item)
subitem not at all important 1 2 3 4 5 essential Does your paper address CONSORT subitem 25? * Copy and paste relevant sections from the manuscript (include quotes in quotation marks "like this" to indicate direct quotes from your manuscript), or elaborate on this item by providing additional information not in the ms, or brie y explain why the item is not applicable/relevant for your study "This research was supported by the University Grants Committee (UGC) (RGC Reference no.: 27612816). The authors would like to all participants who joined this study. We would also like to express our sincere gratitude to Dr K.L. LAW from North District Hospital, the liaison teams from Pamela Youde Nethersole Eastern Hospital and United Christian Hospital for their contribution to the case recruitment. We are also immensely grateful to Miss Chan Pik Ying and Mr Kwok Raymond for their research support. Last but not the least, we thank Erika for the English language review."

X27-i) State the relation of the study team towards the system being evaluated
In addition to the usual declaration of interests ( nancial or otherwise), also state the relation of the study team towards the system being evaluated, i.e., state if the authors/evaluators are distinct from or identical with the developers/sponsors of the intervention. STOP -Save this form as PDF before you click submit To generate a record that you lled in this form, we recommend to generate a PDF of this page (on a Mac, simply select "print" and then select "print as PDF") before you submit it.
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