Background: Adolescent sleep duration can substantially impact mood, behavior, and academic attainment. While hundreds of sleep-related apps are available to download, none have been co-created with adolescents from underserved populations in the UK.

Purpose: The aim of this study was to explore adolescents' views, expectations and experiences with a novel app to improve sleep, called Sleep Solved, to understand which features were perceived as positive and helpful, and to identify ways to further enhance its usefulness. Sleep Solved is part of a larger stepped behavior change study and was co-created with adolescents from underserved groups to make the app accessible and engaging for this population.

Methods: Sixty-three participants aged 16-18 from across the UK completed semi-structured interviews after trying the app. Interviews were analyzed using inductive thematic analysis, as outlined by Braun and Clarke (2006), with a particular focus on the views of individuals from underserved ethnic and socioeconomic groups.

Results: Participants perceived Sleep Solved as a useful tool that provides helpful advice regarding changeable behaviors to improve sleep hygiene. Co-created features of the app, such as the Sleep Stars gamified rewards system and the easy-read, science-based ‘sleep hacks’, were viewed positively by participants, who reported that it had a beneficial impact on their sleep and sleep schedule. Praise was given for the app’s ease of use, and how the science of sleep was explained at an appropriate level, without being overwhelming. Compared to sleep advice on social media platforms, Sleep Solved was considered more reliable and trustworthy. Participants described better sleep hygiene, such as a regular sleep routine and a longer sleep duration, and increased feelings of improved mood and energy.

Conclusions: This study found that a co-created sleep app, designed with input from adolescents in underserved UK populations, was perceived as accessible, reliable, and effective in supporting positive sleep behavior change. Although sleep duration was not objectively tested, participants, particularly those from low socioeconomic status (SES) backgrounds and diverse ethnicities, reported improved sleep routines and mood, highlighting the potential of co-designed digital tools to engage and benefit adolescent users.

Keywords: behavior change; digital intervention; insomnia; depression; anxiety; sleep; qualitative research; adolescents; underserved populations; co-created digital app; sleep hygiene.