Inclusion of underserved young people in digital public health interventions for mental health, sexual health and substance use: A systematic review and intervention component analysis.

Objective: This review examined the design features of digital public health interventions for mental health, sexual health and substance use that may affect equitable reach, engagement, and effectiveness for underserved young people. Materials and methods: We searched MEDLINE, Embase and PsycINFO for relevant systematic reviews published since 2020. We assessed them using the Peer Review of Electronic Search Strategies guidelines. We extracted randomised trials from six reviews and used them to inform searches in PsycINFO and CENTRAL for additional trials. We included mental health, sexual health and substance use interventions delivered solely or primarily through digital technologies to those aged 13-25 from underserved groups. Results: We included 62 trials of 56 interventions. Thirty-eight were sexual health interventions. We identified four coproduction components and six delivery components which may engage young people with interventions and turn knowledge into action. Evidence of effectiveness was strongest for substance use, with mixed or non-significant effects across other behavioural and biological outcomes. Discussion: Similar delivery components were evidenced across all outcome domains and underserved groups, indicating potential synergies in the ways interventions may help young people to navigate these interlinked issues. Coproduction was not well evidenced outside of sexual health interventions and those for sexual and ethnic minoritised youth. Conclusion: Whilst there is some indication of effectiveness for tailored interventions, further evaluations across a broader range of underserved groups are needed. Our framework supports an understanding of how tailored interventions may work for underserved young people that may inform future intervention design and evaluation.