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 (