Digital and online Single-Session Interventions (SSIs) are becoming increasingly used and researched for children and young people’s mental health, due to the rise in digital technologies that can make mental health provision more accessible, and due to the increase in demand on youth mental health services. This thesis aimed to explore digital SSIs in youth mental health. Part one of this portfolio presents a systematic review on the effectiveness of digital SSIs for youth mental health. The findings suggested that online SSIs can be effective for depression and hopelessness, but less so for anxiety, as well as limitations in the long-term effects of these programmes. Thematic analysis was also undertaken to explore the factors that contribute to effectiveness, where the simplicity of SSIs was criticised, but accessibility, helpfulness and connection were positive themes that emerged.

Part two presents an empirical study of the creation and pilot of a new online SSI influenced by Solution-Focused Brief Therapy (SFBT), with a focus on self-esteem for 16–18-year-olds. The SSI was created via Public and Patient Involvement with participants of this age range and piloted in secondary schools to determine the acceptability and feasibility of this intervention. Post-intervention feedback and focus groups of participants contributed to qualitative data that was analysed thematically. Findings demonstrated that the SSI was effective in improving confidence levels and self-esteem, suggesting that an online self-guided SSI based on SFBT can be feasible. Recruitment and uptake of participants via secondary schools was a challenge, and completion rates of the SSI (55.77%) indicated room for improvement. Thematic analysis demonstrated that the SSI’s helpfulness and accessibility were key strengths, and relevance of the SSI itself and those it was reaching was brought into question. Future development could explore the SSI’s relevance further, and test effectiveness in larger, more diverse samples.