Targeting Alcohol-Opioid Co-Use Among Young Adults Using a Novel MHealth Intervention

Inclusion criteria

• . Ages 18 to 25 years, inclusive
• . 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).
• . 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.
• . Able to understand written and oral instructions in English, communicate understanding of the consent form, and provide written informed consent.
• . Complete all assessments required at screening.
• . 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.
• . Own a smartphone with data plan. Almost all participants (98%) in our preliminary work owned a smartphone with data plan.