Adaptive Interventions for Prevention/Intervention for Youth Substance Abuse

The main aim of this formative study is to test and iteratively refine a new mobile phone app, which delivers assessments and tailored intervention content. The study will use social media advertisements to recruit a total of 40 youth between the ages of 16-24 years. Those screening positive for past-month binge drinking or marijuana use will be invited to complete a baseline survey, download and use the app for 30 days, and complete a follow-up survey about the app functionality, design and content, and preliminary outcomes (intentions and importance of reducing use).

Previously, the study team developed a prototype mobile application which utilized novel engagement strategies to enhance user adherence with daily and weekly survey assessments. The new app developed for this study extends the previous app by featuring the capability to also deliver tailored health intervention. As part of the app, users are prompted to complete brief daily and weekly assessments for 30 days. For each completed assessment, users earn small financial rewards and points to unlock new fish that populate a virtual aquarium in the app. The app also features push notifications with survey reminders and life insights (or graphs plotting data collected over time) to increase user engagement with the app. Additionally, each day, users are randomized to receive intervention content (see the "Interventions" section for more information) tailored on their recent assessment responses. After 30 days of using the app, participants will be asked to complete a follow-up survey; data collected will provide preliminary feedback regarding the feasibility and effectiveness of using the app to deliver substance use intervention content to affected youth.

Each day, each available participant will be randomly assigned to receive either: a push notification with tailored intervention content; a push notification with engaging, nontherapeutic content; or no push notification.

Participants will receive a push notification with a therapeutic message (e.g., about stress, mood, substance use motives, tools to reduce risky substance use) tailored to their recent daily or weekly survey responses. Messages include visual (memes, images, videos) and written content.

Participants will receive a push notification with an engaging, non-therapeutic message (e.g., fun facts).

Change in intentions to reduce alcohol use will be assessed using a 10-point validated Likert item which asks participants to rate their current likelihood of cutting back on their alcohol use. (a score of 1 is equivalent to not at all likely and a score of 10 is very likely)

Change in importance of reducing alcohol use will be assessed using a 10-point validated Likert item which asks participants to rate how important it is to them to cut back on their alcohol use. (a score of 1 is equivalent to not at all important and a score of 10 is very important)

Change in intentions to reduce marijuana use will be assessed using a 10-point validated Likert item which asks participants to rate their current likelihood of cutting back on their marijuana use. (a score of 1 is equivalent to not at all likely and a score of 10 is very likely)

Change in importance of reducing alcohol use will be assessed using a 10-point validated Likert item which asks participants to rate how important it is to them to cut back on their marijuana use. (a score of 1 is equivalent to not at all important and a score of 10 is very important)

Inclusion Criteria: Have an iPhone smartphone on which the app can be downloaded Self-reported past-month binge drinking (4/5 or more drinks on one occasion, tailored by sex) OR any past-month marijuana use without a medical marijuana card Meet study verification criteria (i.e., use of CAPTCHA, IP address checks, social media checks). Exclusion Criteria: 1. Unable to understand English