Can a digital intervention 'Momentum' improve social functioning and transdiagnostic symptoms for Australian youth at ultrahigh risk for psychosis? Protocol for a superiority randomised controlled trial comparing treatment as usual with and without Momentum.

INTRODUCTION: Existing psychological and pharmacological interventions for young people at ultra-high risk (UHR) for psychosis have shown benefit in at least delaying the transition to psychosis, but they have limited benefit for comorbid disorders or social dysfunction, which are prominent for those at UHR. We developed a moderated online social therapy platform (named Momentum) including: (1) transdiagnostic therapeutic interventions targeting social functioning, depression, generalised anxiety and social anxiety; (2) a moderated, peer-led online community and (3) specialised human support from clinicians, career consultants and peer workers. The aim of this trial is to determine whether, in addition to treatment as usual (TAU), Momentum, a 12-month digital intervention, informed by the complex intervention framework, is superior to 12 months of TAU in improving social functioning in UHR young people. METHODS AND ANALYSIS: The study design is a prospective, parallel group, rater-masked randomised controlled trial. We will recruit young people aged 14-27 years, meeting one or more UHR for psychosis criteria. Participants are randomly assigned to the condition using randomly permutated blocks with a 1:1 allocation ratio. Participants are stratified by age (<18 years and ≥18 years), sex at birth and recruitment site. A total of 220 young people will be recruited, allowing for an 18% attrition rate following randomisation. The study includes a 12-month treatment phase, with assessment points at baseline, and 4 months, 8 months and 12 months. The primary outcome is social functioning, as measured by the Global Functioning Social Scale. Secondary outcomes include the severity of depressive and anxiety symptoms, social anxiety, role functioning, study and employment outcomes and cost-effectiveness. We will also examine potential mechanisms to understand Momentum's therapeutic impact on social functioning. Primary analyses will be undertaken on an intention-to-treat basis. Mixed-model repeated measures analyses will be used to compare change in social functioning between the two treatment groups over the 12-month follow-up for primary, secondary and exploratory outcomes. ETHICS AND DISSEMINATION: Melbourne Health Human Research Ethics Committee (HREC/42964/MH-2018) provided ethics approval for this study. Findings will be made available through scientific journals and forums and to the public via social media and the Orygen website. De-identified individual participant data will be available after publication for 3 years via the Health Data Australia catalogue (https://www.researchdata.edu.au/health). Requests must include a methodologically sound proposal. Specific conditions of use may apply and will be specified in a data sharing agreement (or similar) that the requester must agree to before access is granted. Supplementary material including study protocol, informed consent material and statistical analysis plan will also be available. TRIAL REGISTRATION NUMBER: Australian New Zealand Clinical Trial Registry (ANZCTR), ACTRN12619001411134.