TIPS (The Trans-Tasman Internet-delivered Prevention of (youth) Suicide) Study: Protocol for a Randomised Controlled Trial of Mobile Health Interventions (four apps) to help young people reduce suicidal ideation

IntroductionSuicidal ideation is common in young people and increases the risk of suicide. Effective interventions that are relevant and accessible to young people, so-called digital natives, are urgently required. There are key questions regarding the cross-cultural efficacy of suicide prevention apps for scalability. Methods and analysisThis online four-arm parallel randomised controlled superiority trial will enrol 1480 young people aged 16-24 with current suicidal ideation in New Zealand and Australia. Participants will be randomised to one of three therapeutic apps developed in different countries, Tune In, Bro and LifeBuoy, or to My Mood (attention control). The primary outcome is suicidal ideation severity at 30-day and 90-day post-baseline; secondary outcomes include mental well-being, engagement and acceptability. Emotional regulation will be examined as a mediator of change in suicidal ideation. All outcomes are measured by self-reported scales incorporated in an online questionnaire. Acceptability of the apps for rangatahi M[a]ori (Indigenous youth, New Zealand) will be explored via semi-structured interviews. Linear mixed models with repeated measures analyses, employing maximum likelihood estimation, an appropriate covariance structure, and consideration of site effects, will be undertaken. Examination of individual app intervention effects in New Zealand and Australia will highlight the effects of apps developed for a different country. Ethics and disseminationApproval was obtained (26 February 2025) from the Health and Disability Ethics Committees (Ministry of Health ref 2025 EXP 21500). It was registered in the Australian New Zealand Clinical Trials Registry ACTRN12625000349448 23/04/2025; recruitment started on July 14, 2025 (594 recruited to date), and is expected to be complete by June 2026. Participants provide informed consent online. Trial results will be submitted for publication in peer-reviewed journals, shared on relevant websites, and via presentation at international scientific conferences; IPD will only be shared if requested and subsequent to review. Article SummaryO_LIThis is one of the largest online trial of suicide prevention apps in young people ever undertaken. C_LIO_LIThis trial will test several different suicide prevention apps in a four-arm parallel superiority randomised trial design. C_LIO_LIThe trial will specifically examine the cross-cultural efficacy of apps by testing the effectiveness of an app developed in a country different from where it is being tested. C_LI Strengths and limitationsO_LIThere is a risk of fraudulent behaviour in online trials; in this trial, this primarily consists of providing false information to ensure eligibility. Targeted social media advertising (for age and location) for recruitment will minimise risks. SMS verification ensures protection against bots and multiple accounts. C_LI