Abstract
<p>IntroductionEmotion dysregulation (ED) is a commonly associated feature of attention deficit hyperactivity disorder (ADHD) in adolescence, yet there is a lack of scalable interventions tailored for those with ADHD symptoms. The present article outlines the protocol for a mixed-methods single-arm small-scale efficacy trial study evaluating a novel digital health intervention (DHI) in the form of a smartphone app designed to address this gap. The intervention was co-designed with adolescents with ADHD and draws on therapeutic approaches such as psychoeducation, dialectical behaviour therapy and emotion-focused variants of cognitive behavioural therapy.Methods and analysisThe study will use a mixed-methods pre–post design involving up to 100 participants, comprising 50 adolescents aged 11–15 years who have an ADHD diagnosis or are on a waitlist for assessment and moderate-to-severe ED, and up to 50 parents/caregivers participating as optional informants. Young people will use the intervention over a four-week period. Quantitative outcomes, including ED, adaptive ER strategy use, anxiety, and depression, will be assessed at baseline and follow-up using self-report and optional parent-report measures. Quantitative engagement data will additionally be passively collected through the DHI software. Qualitative interviews will be conducted to obtain complementary, in-depth data on user experience, perceived engagement, and the feasibility of the DHI use. Quantitative data will be analysed using linear mixed-effects regression models, and qualitative data will be analysed using thematic analysis.Ethics and disseminationThe study received multi-tiered ethical approval by the College of Arts, Humanities and Social Sciences, as well as the School of Philosophy, Psychology and Language Science at the University of Edinburgh. Additionally, the study obtained favourable ethical opinion by the National Health Service (NHS) research ethics committee. Findings will be disseminated through peer-reviewed publications, conference presentations, and accessible co-produced summaries shared with relevant stakeholder groups, including young people, families, clinicians, and ADHD charities.</p>