Adherence and efficacy outcomes in young Australians with suicidal ideation using a self-management app and digital engagement strategy compared with a sham app: a three-arm randomised controlled trial.

Background: Digital interventions are important treatment solutions for suicidal ideation, but premature disengagement is a significant threat to their effectiveness. We tested the adherence to, and efficacy of, two versions of an app-based intervention (app only, app + engagement strategy) for suicidal ideation, compared to a sham app. Methods: This was an online double-blind, three-arm parallel randomised controlled trial in Australia. Recruitment occurred between May 30 and August 8, 2023 and eligible participants were aged 17-24 years and had suicidal ideation in the prior 30 days. They were randomly assigned 1:1:1 to receive (i) LifeBuoy-an app which delivered third wave cognitive behavioural therapy (CBT) skills, (ii) the LifeBuoy app plus a digital engagement strategy, or (iii) a sham app to minimise expectancy bias. The primary efficacy outcome was change in suicidal ideation scores, measured by the Suicidal Ideation Attributes Scale (SIDAS), at 30-, 60- and 120- days post-baseline. The primary engagement outcome was the number of app modules completed at 60-days post-baseline. The final assessment occurred on December 6, 2023. All data was analysed using intention-to-treat. This trial was registered at anzctr.org.au, trial number: ACTRN12621001247864. Findings: 692 participants were assigned (mean age: 19.9 [SD 2.5]; 70% female; intervention (combined): n-459, control: n-233). Significant reductions in ideation scores were observed in the combined intervention condition at 60- (d 0.48) and 120- (d 0.29) days after random assignment compared to the control condition. There were no differences in the number of modules completed between the intervention conditions (OR 1.10, 1.03, respectively) and no significant differences in their ideation scores at any time (ds -0.15 to 0.08). Serious adverse events (hospital presenting non-suicidal self-harm and/or suicide attempts) were reported by 6% of participants during the trial (control condition: 9%; combined intervention condition: 4%). No deaths were reported. Interpretation: A third wave CBT app helped to reduce ideation severity, however providing additional online resources to promote therapeutic engagement did not enhance these effects. Funding: This trial and MT was funded by the National Health & Medical Research Council, Matana Foundation for Young People, Alex Roth Foundation.