Lumen
Lumen is a virtual voice-based coach developed on Amazon’s Alexa platform. Lumen delivers an evidence-based PST program [Lumen was designed through an iterative user-centered process that involved software developers, interaction designers, psychiatrists, PST experts, and behavioral scientists. Several iterations of the prototype were internally tested; a fully functional prototype underwent feasibility and usability testing with 26 users [For this study, Lumen was integrated within the Alexa app on an iPad provided to all participants. Lumen participants attended an in-person orientation session with a trained health coach where they received their iPad, intervention workbook, and completed a tutorial on how to interact with Lumen. Participants were instructed to begin their PST right away, within 1 week of their orientation session and the health coach helped schedule their 4 weekly and the following 4 biweekly PST sessions. Within 3 days of their first scheduled PST session, the health coach called participants to inquire about any technical issues and helped troubleshoot these issues (if any). Participants received reminder text messages about their upcoming and overdue (if any) PST sessions. Participants with overdue sessions, even after their reminders, were called by the health coach and encouraged to complete their outstanding session(s). Participants also had the opportunity to reach out to the health coach if they faced any issues as part of their study.For each session, participants instantiated Lumen PST through the Alexa app with a “Launch Lumen Coach” voice instruction and completed their assigned PST sessions. A typical Lumen session lasted ~12 min. Between sessions, participants completed surveys and ecological momentary assessments (EMAs, see 