Decision-making by laypersons equipped with an emergency response smartphone app for opioid overdose

Background: Targeted naloxone distribution to potential lay responders increases the timeliness of overdose response and reduces mortality. Little is known, however, about the patterns of decision-making among overdose lay responders. This study explored heuristic decision-making among laypersons equipped with an emergency response smartphone app. Methods: UnityPhilly, a smartphone app that connects lay responders equipped with naloxone to overdose victims, was piloted in Philadelphia from March 2019 to February 2020. Participants used the app to signal overdose alerts to peer app users and emergency medical services, or respond to alerts by arriving at overdose emergency sites. This study utilised in-depth interviews, background information, and app use data from a sample of 18 participants with varying histories of opioid use and levels of app use activity. Results: The sample included 8 people who used opioids non-medically in the past 30 days and 10 people reporting no opioid misuse. Three prevailing, not mutually exclusive, heuristics were identified. The heuristic of unconditional signalling ( "Always signal for help or backup ") was used by 7 people who valued external assistance and used the app as a replacement for a 911 call; this group had the highest number of signalled alerts and on-scene appearances. Nine people, who expressed confidence in their ability to address an overdose themselves, followed a heuristic of conditional signalling ( "Rescue, but only signal if necessary "); these participants had the highest frequency of prior naloxone administrations. Eleven participants used the heuristic of conditional responding ( "Assess if I can make a difference "), addressing an alert if they carried naloxone, were nearby, or received a signal before dark hours. Conclusion: The deployment of specific heuristics was influenced by prior naloxone use and situational factors. Success of overdose prevention interventions assisted by digital technologies may depend on the involvement of people with diverse overdose rescue backgrounds.