Opioid use disorders (OUD) are the second most common type of drug use disorder in the US, with nearly 2 million reporting prescription opioid (PO) use and \~570,000 reporting heroin use consistent with an OUD. Further, drug overdose (OD) has become the leading cause of accidental death in the US, with opioid-involved OD driving this epidemic. The recent escalation in OUD has been most pronounced among youth, with nearly 1/3 of youth reporting PO misuse by age 21, and studies have documented the trajectory from PO misuse to injection drug use (IDU) in youth. An ongoing study conducted by the current investigators documented an alarming trajectory, wherein these youth progress from nonmedical PO use in adolescence (first PO use M=16.7 y/o), to oral / intranasal heroin use in young adulthood (M=19.1 y/o), with 64% progressing to injection drug use (IDU), within a year of heroin initiation (first injection M=20.1 y/o. This progression to IDU is characterized by uniquely high levels of risk for youth, including higher rates of injection risk behaviors and OD, and higher incidence of HIV and HCV within the first few years of transitioning to injection, compared to older peers. Thus, young opioid users are at uniquely high risk for a number of negative outcomes during the critical period of transitioning to injection. This rapid progression from PO use to IDU and the extreme risk associated with new injection status among youth indicate that there is a brief, but critical, period during which we may intervene to prevent progression to injection and its associated risk behaviors and negative health outcomes. Several robust predictors have been found for progression to IDU, including psychosocial factors (i.e., homelessness, physical abuse), OUD severity (i.e., dependence severity, polydrug use), and IDU norms and behaviors within one's social network. While there is some understanding of the mechanisms that promote IDU, there is virtually no research on strategies to prevent this transition. Only one intervention has been examined targeting intranasal heroin users in an attempt to prevent progression to IDU. This "sniffers" intervention found potent effects; half as many intervention participants progressed to injection (33% vs. 16%), compared to the control condition (who received HIV/AIDS education), indicating that direct intervention with opioid users may be an effective way to prevent progression to IDU and its associated harms. It is unclear why so few interventions have targeted this population, although young opioid users face a number of unique barriers, including social, economic, and motivational, that may prevent them from seeking and receiving treatment. Given the paucity of interventions available to the large and vulnerable group of opioid-using young adults, there is an urgent need to develop and evaluate innovative, engaging approaches to prevent young opioid users from transitioning to IDU.

The current application is being submitted in response to PA 16-073, "Behavioral and Integrative Treatment Development Program." The proposed project is a Stage Ib study that will adapt a mobile, evidence-based psychosocial intervention for opioid dependence (Check-In App) to prevent progression to injection in young opioid users (18-29 y/o) who have not progressed to regular injection.

Aim 1: During months 1-12, we will adapt the Check-In App to target reducing opioid use and preventing progression to injection among young oral / intranasal opioid users. We will tailor our existing mHealth intervention (including daily text messages plus key components of evidence-based cognitive behavioral interventions, Functional Analysis of Drug Use, Self-Management, and Social / Recreational Counseling), for young opioid users. New components specific to youth will focus on the role of peers in opioid use / IDU, and OD prevention / response training including use of naloxone. Our iterative development process will include focus groups with opioid-using youth (n=24), interviews with important stakeholders (e.g., youth treatment providers; n=6), and feedback and usability data from opioid-using youth (n=30).

Aim 2: During months 13-31, we will conduct a small randomized, controlled trial of the newly tailored mHealth intervention with young opioid users (18-29 y/o) who have not transitioned to regular injection (n=64) and compare (1) assessment plus in-person OD prevention / response training (including naloxone) versus (2) assessment plus in-person OD prevention / response training (including naloxone) plus the Preventing Injection Application. We will evaluate the intervention's feasibility, acceptability, diffusion, and preliminary effectiveness. Feasibility and acceptability will be assessed via participant feedback, retention, and app usage data. Diffusion will be defined as the number of participants' peers who download the intervention app for their own use. Preliminary effectiveness will be measured via reductions in opioid use (TLFB, urine and hair toxicology) and self-reported injection status at 4, 8, and 12 weeks, and 3 and 6 month follow-up. Secondary outcomes include HIV/HCV risk behavior, OD episodes, opioid-related problems (e.g., withdrawal episodes), and social network IDU-related norms and behaviors.

If results are promising, this intervention will be evaluated in a large-scale efficacy / effectiveness trial. This intervention may have tremendous impact on improving access, acceptability, and potency of opioid use interventions for youth, given the extremely widespread use of mobile apps among young adults (98% of 18-29 y/o own mobile phones and spend \~3 hr/day using mobile apps).