Web-App Prevention Program Reduced Cannabis Use in Diverse College Students | Research

The takeaway

A culturally sensitive web-app prevention program reduced cannabis use incidence and improved substance knowledge among diverse college students at a Hispanic Serving Institution.

University prevention program administrators, mHealth developers, public health researchers working with diverse student populations.

1,066 students randomized across 3 conditions

What the researchers found

Among 1,066 students randomly assigned to a web-app intervention, comparison, or control condition, those in the 5-module web-app group had significantly greater substance knowledge gains, more accurate peer use perceptions, and better understanding of health risks than comparison or control students. Web-app students also had lower incidence rates of cannabis use at program exit, with effects persisting at 90-day follow-up.

Why it matters

First-generation, working, and ethnic minority college students are underrepresented in substance use prevention research. This study demonstrates that a culturally sensitive digital intervention can effectively reach these populations and produce lasting reductions in cannabis use, filling a critical gap in prevention science.

The numbers in context

1,066 participants. Three conditions: web-app, comparison, control. Cannabis use reduction at exit and 90-day follow-up. Significant improvements in substance knowledge, peer norm accuracy, and health risk perception. Hispanic Serving Institution in Southern California.

How the study worked

Randomized controlled trial with 1,066 participants at a Hispanic Serving Institution in southern California. Students were randomly assigned to control, comparison, or 5-module web-app condition. Surveys assessed knowledge, perceived health risks, normative peer use, and past 30-day substance use at baseline, exit, and 90-day follow-up.

What this study cannot tell us

Single institution in Southern California. Self-reported substance use. 90-day follow-up is relatively short for assessing lasting behavior change. Cannot determine which specific modules drove the effects. Nicotine use reduction did not persist at follow-up.

How to read the evidence

Moderate: randomized design with large sample and follow-up, though single-institution and relatively short follow-up period.

When this study was published

2025 study

The bigger picture

Digital prevention tools can scale to reach populations that traditional programs miss. The success of this web-app among first-generation and minority students suggests that culturally adapted digital interventions could be a cost-effective strategy for reducing substance use disparities.

Questions still open

Would the effects persist beyond 90 days? Which specific program modules were most effective? Could the web-app be adapted for other demographic groups or settings?

Common questions

Can a phone app reduce cannabis use in college students?

This 5-module web-app significantly reduced cannabis use and improved substance knowledge among diverse college students, with effects lasting at 90-day follow-up.

Did the program work for minority students?

Yes. The program was specifically designed for and tested at a Hispanic Serving Institution with first-generation and ethnic minority students, showing effectiveness in a population typically underserved by prevention programs.

Read the original research

Evaluation of iSTART: A Novel Substance Use Prevention Web-App Designed for Diverse College Students.

Evaluation & the health professions, 48(2), 163-173

View on PubMed ↗Publisher’s paper ↗

Citation

Rainisch, Bethany K W; Dahlman, Linn; Shahverdi, Abnous; Alhassan, Sarah; Forster, Myriam. (2025). Evaluation of iSTART: A Novel Substance Use Prevention Web-App Designed for Diverse College Students.. Evaluation & the health professions, 48(2), 163-173. https://doi.org/10.1177/01632787251322996