Precision computerised cognitive behavioural therapy (cCBT) intervention for adolescents with depression (SPARX-UK): protocol for the process evaluation of a pilot randomised controlled feasibility trial.

INTRODUCTION: While digital technologies can increase the availability and access to evidence-based interventions, little is known about how users engage with them and the mechanisms associated with effective outcomes. Process evaluations are an important component in understanding the aforementioned factors. The 'SPARX-UK' study is a randomised controlled pilot and feasibility trial evaluating personalised human-supported (from an 'eCoach') vs a self-directed computerised cognitive behavioural therapy intervention (cCBT), called SPARX (Smart, Positive, Active, Realistic, X-factor thoughts), aimed at adolescents with mild to moderate depression. We are comparing supported vs self-directed delivery of SPARX to establish which format should be used in a proposed definitive trial of SPARX. The control is a waitlist group. We will conduct a process evaluation alongside the trial to determine how the intervention is implemented and provide context for interpreting the feasibility trial outcomes. We will also look at the acceptability of SPARX and how users engage with the intervention. This protocol paper describes the rationale, aims and methodology of the SPARX-UK trial process evaluation. METHODS AND ANALYSIS: The process evaluation will use a mixed-methods design following the UK Medical Research Council's 2015 guidelines, comprising quantitative and qualitative data collection. This will include analysing data usage of participants in the intervention arms; purposively sampled, semi-structured interviews of adolescents, parents/guardians, eCoaches and clinicians/practitioners from the SPARX-UK trial; and analysis of qualitative comments from a survey from those who dropped out early from the trial. Quantitative data will be analysed descriptively. We will use thematic analysis in a framework approach to analyse qualitative data. Quantitative and qualitative data will be mixed and integrated to provide an understanding of how the intervention was implemented and how adolescents interacted with the intervention. This process evaluation will explore the experiences of adolescent participants, parents/guardians, eCoaches and clinicians/practitioners in relation to a complex digital intervention. ETHICS: Ethical approval was granted by the National Health Service (NHS) Health Research Authority South West - Cornwall & Plymouth Research Ethics Committee (Ethics Ref: 22/SW/0149). DISSEMINATION: Contextualising how the intervention was implemented, and the variations in uptake and engagement, will help us to understand the trial findings in greater depth. The findings from this process evaluation will also inform the decision about whether and how to proceed with a full randomised controlled trial, as well as the development of more effective interventions which can be personalised more precisely via varying levels of human support. We plan to publish the findings of the process evaluation and the wider project in peer-reviewed journals, as well as disseminate via academic conferences. TRIAL REGISTRATION NUMBER: ISRCTN: ISRCTN15124804. Registered on 16 January 2023, https://www.isrctn.com/ISRCTN15124804.