Acceptability of the content and functionality of a just-in-time adaptive intervention for gambling problems: a...

BACKGROUND: Just-In-Time Adaptive Interventions (JITAIs) offer real-time support to help individuals adhere to gambling expenditure goals. This mixed-methods study evaluated the acceptability of a JITAI called Gambling Habit Hacker, focusing on both the app’s content and functionality. METHODS: Australian participants who had recently completed a micro-randomized trial of the app provided feedback through semi-structured interviews. Acceptability was further assessed using app usage and engagement metrics, including registration, adherence to the ecological momentary assessment (EMA) protocol, duration and timing of app use, and interaction with intervention content. Subscales of the Mobile App Rating Scale (MARS) were also used. Intervention fidelity was evaluated by examining adherence to the EMA protocol, strategy selection, and action plan completion. RESULTS: Participants (n = 174) completed 4382 EMA entries over a 28-day period, averaging 25 EMAs each, with the highest completion rate observed in Week 1. Of those, 48% were micro-randomized to receive the intervention, and 80% of this group completed at least one intervention. Across the trial, participants created 1307 action and coping plans, most commonly focused on behaviour substitution, initiating rewards, or limiting access to cash. In the post-intervention survey (n = 141), participants reported increased awareness, knowledge, and shifts in attitudes toward gambling, exceeding minimally acceptable thresholds. Semi-structured interviews with 11 participants revealed two primary motivations for using the app: (1) goal setting with monitoring, and (2) goal adherence with an emphasis on managing urges. Qualitative and quantitative findings suggest future optimisation should include customising the timing and frequency of EMAs and adopting a hybrid push–pull approach to intervention delivery. Functionality improvements could also include the ability to save and adjust action plans in real time to enhance responsiveness in high-risk situations. Engagement may be further improved by incorporating additional lived experience content, such as videos and audio recordings. CONCLUSION: Gambling Habit Hacker was found to be acceptable for providing support in adhering to gambling expenditure limits and, over time, reducing gambling spend. Future optimisation could improve its tailoring to individual needs and enhance user engagement. TRIAL REGISTRATION: This trial was registered with the Australian New Zealand Clinical Trials Registry (ACTRN12622000497707) and approved by the Deakin University Human Research Ethics Committee (2020 − 304).