The goal of this observational study is to learn more about changes in health, wellness, and substance-use behaviors as teenagers get older. Participants, ages 13 to 16, will be asked to use a smartphone application developed for this research study. Participants will also come to Brown University or meet via video conference to answer questions about specific behaviors, choices, and feelings that may change over time.

Inclusion Criteria:

1. be age 13 to 16 years
2. engage in a target health behavior on at least one recent occasion
3. speak, read, and understand English or Spanish
4. live in or near Rhode Island

Exclusion Criteria:

1. lifetime history of moderate or severe substance use disorder or treatment, excluding nicotine use disorder
2. current psychotic symptoms or active suicidality (i.e., intent in the past 30 days)

De-identified data that cannot individually identify participants may be shared with researchers internal and external to Brown University upon reasonable request by qualified research collaborators. Data shared with qualified researchers will not contain any protected health information or other personally identifiable information that could be used to identify individual participants.