Material Development and Usability Testing of STOP (Successful Treatment for Paranoia): A Digital Therapeutic for Paranoia (Preprint)

BACKGROUND Paranoia is a highly debilitating mental health condition. One novel intervention for paranoia is cognitive bias modification for paranoia (CBM-pa). CBM-pa comes from a class of interventions that focus on manipulating interpretation bias. Here, we aimed to develop and evaluate new therapy content for CBM-pa for later use in a self-administered digital therapeutic for paranoia called STOP (‘Successful Treatment of Paranoia’). OBJECTIVE 1) take a user-centered approach to create and evaluate paranoia-relevant item content to be used in STOP with input from experts by experience, clinicians, and academics, and 2) engage with experts by experience to pilot test and evaluate feedback from STOP mobile app prototype METHODS We invited people with lived experience of paranoia to create text exemplars of personal, everyday emotionally ambiguous scenarios that could provoke paranoid thoughts. Researchers then adapted 240 suitable exemplars into corresponding intervention items in the format commonly used for CBM training and created 240 control items for the purpose of testing STOP. Each item included newly developed, visually enriching graphics content to increase the engagement and realism of the basic text scenarios. All items were then evaluated by experts by experience, clinicians, and academics for paranoia severity, readability, and length. Items were evenly distributed into six, 40-item sessions. Finalized items were presented in the STOP mobile app and user acceptance was evaluated across two pilot tests involving experts by experience. RESULTS All materials reached predefined acceptable thresholds on all rating criteria: paranoia severity, readability, and length of the scenarios, and there was no systematic difference between intervention and control group materials overall or between individual sessions within each group. For item graphics, we also found no systematic differences in users’ ratings of complexity, attractiveness, and interest, between intervention and control group materials. User acceptance testing of the mobile app found the application easy to use and navigate, interactive, and helpful. CONCLUSIONS Material development for any new digital therapeutic requires an iterative and rigorous process of testing involving multiple stakeholders. Appropriate user-centered development can create user-friendly mobile health applications, which have good face validity, and have a greater chance to be engaging and acceptable to the target end users.