Development and evaluation of a smartphone app targeting harmful drinking in young adults
: how do we promote engagement to improve clinical outcomes?

Student thesis: Doctoral ThesisDoctor of Philosophy


Electronic screening and brief intervention (eSBI) has demonstrated effectiveness in reducing harmful alcohol consumption. However, a challenge remains as to how to sufficiently engage users with eSBI, as trials demonstrate low usage rates. Young adults are an under-identified harmful drinking population who prefer eSBI delivered alcohol interventions. The objectives of this PhD were: (1) to develop a smartphone app, aimed at promoting engagement, targeting harmful drinking in young adults, using an evidence-based and empirically driven methodology, and, (2) evaluate it with a mixed methods approach in a randomised controlled trial (RCT) and qualitative interviews with trial participants. 
The developmental phase included a systematic review of engagement promoting strategies (EPSs) in online substance-use interventions, a review of user feedback reviews of existing eSBI apps and two stages of focus groups to inform the content, features and style of the app. An app called ‘BRANCH’ was developed, including EPSs of tailoring, social features, single exposure of delivery strategies, in-app reminders and gamification. The evaluation phase included an RCT evaluating two versions of the app (comprehensive EPSs versus basic EPSs) and qualitative interviews with trial participants to explore their experiences of app engagement. 
The RCT demonstrated no differences in engagement or reductions in drinking between arms. No associations between level of engagement and harmful alcohol-use were reported. The qualitative interviews identified three distinct typologies of user engagement and highlighted awareness of drinking risks, not reduction, as an outcome of app usage. 
Engagement with eSBI in young adults continues to be a barrier for designing effective eSBI apps. The associations between EPSs, engagement and drinking outcomes remain unclear. How best to measure engagement, develop future eSBI apps and the clinical implications of ongoing-use of alcohol eSBI are discussed.
Date of Award1 Feb 2019
Original languageEnglish
Awarding Institution
  • King's College London
SupervisorPaolo Deluca (Supervisor), Colin Drummond (Supervisor) & Andreas Kimergård (Supervisor)

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