Table 1.

Incorporating the NIDA prevention principles into the app development.

NIDA prevention principles	How this was accomplished
Principle 1: Programs should enhance protective factors and prevent and reduce risk factors.	S4E aims to improve clinician-adolescent HIV/STI and drug use communication, condom use and drug use resistance self-efficacy, and increase HIV/STI testing.
Principle 2: All forms of licit and illicit drug abuse should be addressed.	The Alcohol/Drugs module includes both licit and illicit drugs, including abuse of medication without a doctor’s prescription.
Principle 3: Programs should address culturally specific risk and protective factors and licit and illicit drug use in the targeted community.	In-depth qualitative data informed the development of culturally specific content, including risk and protective factors and licit and illicit drug use.
Principle 4: Prevention programs should be tailored to address risks specific to the targeted community, including age, gender, and race, to improve program effectiveness.	The community-engaged approach aimed to identify risks specific to the targeted community.
Principle 8: Programs targeting high-school students should increase social competence skills, including communication, self-efficacy, and drug-resistance skills.	S4E aims to improve clinician-adolescent HIV/STI and drug use communication, self-efficacy, and drug-resistance skills.
Principle 9: Programs aimed at key transition points, including the transition to young adulthood, may yield beneficial effects.	S4E targets those in adolescence and young adulthood, a transitional period marked by increased risk taking.
Principle 12: Adapted programs should retain the core elements of the original research-based intervention.	We retained the core elements (knowledge development, self-efficacy, and communication) of the face-to-face Storytelling for Empowerment intervention.
Principle 13: Programs should be long-term, including the use of booster sessions.	An mHealth app may provide opportunities for adolescents to engage in long-term prevention, including booster sessions.
Principle 15: Prevention programs should include interactive exercises to work toward optimally effective interventions.	S4E incorporates interactive exercises. Additionally, we plan to develop a clinician component to allow interaction and retrieval of adolescents’ risk assessment data, with an aim of improving clinician-adolescent interaction, including HIV/STI and drug use communication.
Principle 16: Research-based programs can be cost effective.	mHealth apps, including S4E, have the potential to be cost effective through greater reach to populations disproportionately affected by HIV/STI and drug use, as well as by relieving some of the responsibilities and sparing resources in a clinic setting.