The goal of this treatment development project is to develop and pilot an adaptive mobile health (mHealth) intervention that targets the co-use of alcohol and opioids in young adults.

The goal of this treatment development project is to develop and pilot an adaptive mobile health (mHealth) intervention that targets the co-use of alcohol and opioids in young adults. Alcohol is an under-recognized contributor to the opioid crisis that, when used with opioids, substantially increases the risk of opioid overdose and other use-related problems. Despite clear public health significance, however, no existing intervention targets alcohol-opioid co-use. This gap is especially detrimental to young adults aged 18-25, who have the highest rates of alcohol and opioid (i.e., nonmedical prescription opioid or heroin) use and use disorders of any age group. Over half of young adults who use nonprescription opioids report past-year alcohol-opioid co-use, yet few young adults receive treatment for either substance. MHealth interventions, which use technology (e.g., smartphone applications) to intervene in daily life, are highly accessible and acceptable to young adults. MHealth thus offers a means of targeting alcohol-opioid co-use that can reach young adults not currently in treatment. However, developing an effective mHealth intervention requires an ecologically valid understanding of the target behavior, which does not exist for alcohol-opioid co-use. Thus, the first step of the proposed project is to use ecological momentary assessment (EMA), wherein 60 young adults (ages 18-25) with mild to moderate OUD who report regular alcohol-opioid co-use will complete EMA multiple times daily via smartphone for 3 weeks to examine how, why, and when young adults co-use alcohol and opioids in real-time in their daily lives. Using established guidelines for developing mHealth interventions, the investigators will then use this EMA knowledge base to develop a smartphone-based mHealth platform targeting alcohol-opioid co-use. The intervention will be founded on principles of motivational enhancement therapy and cognitive behavioral therapy and deliver tailored micro-interventions based on participants' responses to EMA assessments. The investigators will refine the intervention based on feedback from two iterative usability studies with 10 participants. Finally, in a new sample of 60 young adults, participants will use the intervention for 28-days. The investigators will evaluate the intervention's feasibility, acceptability, and putative mechanisms of action. This study will address national priorities to respond to the accelerating opioid crisis. It will provide vital new information on the nature of alcohol-opioid co-use in daily life and develop and pilot an innovative adaptive mHealth intervention to address this behavior in young adults.

Inclusion Criteria:

1. Ages 18 to 25 years, inclusive
2. Self-report interest in reducing their alcohol-opioid co-use - outside a research study, people who do not wish to change their co-use are unlikely to download and use an mHealth app designed to reduce co-use. It is important to recruit participants who most closely resemble the intended users of the eventual mHealth intervention. This is defined as reporting any alcohol-opioid co-use goal (i.e., not selecting "No goal" in response to the alcohol-opioid co-use goal question at the screening visit).
3. Self-report engaging in simultaneous alcohol-opioid co-use (i.e., use of both substances within two hours) ≥ 1 day/week on average in the past 28 days (i.e., at least 4 co-use events in the past 28 days). This requirement will ensure that we observe sufficient use episodes where the pharmacological effects of alcohol and opioids overlap to evaluate project aims.
4. Able to understand written and oral instructions in English, communicate understanding of the consent form, and provide written informed consent.
5. Complete all assessments required at screening.
6. Agree to the schedule of visits, verbally acknowledge that he/she/they will be able to attend each scheduled visit, participate in phone visits and that he/she/they does not have any already scheduled events or a job that may substantially interfere with study participation.
7. Own a smartphone with data plan. Almost all participants (98%) in our preliminary work owned a smartphone with data plan.
8. Currently reside in the United States of America.

Exclusion Criteria:

1. Pregnant or nursing
2. Current suicidality
3. History of psychosis