A smartphone app showed early promise for reducing cannabis-impaired driving among young Canadians
The "High Alert" smartphone intervention was well received by young cannabis users and showed preliminary efficacy in reducing driving after cannabis co-use, though recruitment barriers and high attrition posed challenges.
Quick Facts
What This Study Found
High Alert, a digital smartphone intervention for youth DUIC, was positively received by participants and showed preliminary efficacy in reducing driving after cannabis co-use compared to a no-contact control. However, implementation challenges including online bot activity, recruitment barriers, and high attrition rates were significant.
Key Numbers
Most participants were willing to engage with the app and recommend it to peers. Content and delivery ratings exceeded those of static infographics. Preliminary efficacy was shown for reducing driving after cannabis co-use vs. no-contact group.
How They Did This
Pilot randomized controlled trial comparing High Alert (smartphone intervention) to an active control (DUIC infographics) and a passive control (no contact), evaluated using the six-step Intervention Mapping framework including formative, process, outcome, and acceptability evaluations.
Why This Research Matters
Cannabis-impaired driving among youth is a growing concern in jurisdictions with legalized cannabis. Digital interventions are scalable, but this study highlights the practical challenges of deploying them to high-risk young populations.
The Bigger Picture
This study demonstrates both the potential and the pitfalls of digital health interventions for substance-related driving behaviors. The recruitment and retention challenges reported are common across digital intervention research with young adults.
What This Study Doesn't Tell Us
Pilot study with small sample size. High attrition limits generalizability. Bot activity during online recruitment complicated data quality. Active control group may have also received benefit from infographic exposure.
Questions This Raises
- ?Can High Alert be scaled effectively given the recruitment and retention challenges?
- ?Would combining the app with in-person touchpoints improve engagement?
Trust & Context
- Key Stat:
- Preliminary efficacy for reducing co-use driving
- Evidence Grade:
- Pilot RCT with small sample, high attrition, and implementation challenges. Provides proof of concept but not definitive efficacy evidence.
- Study Age:
- 2025 publication
- Original Title:
- Using intervention mapping to evaluate 'High-Alert,' a brief smartphone intervention to reduce youth cannabis-impaired driving.
- Published In:
- PloS one, 20(8), e0329383 (2025)
- Authors:
- Colonna, Robert(4), Tucker, Patricia, Mandich, Angela, Alvarez, Liliana
- Database ID:
- RTHC-06246
Evidence Hierarchy
A small preliminary study to test whether a larger study is feasible.
What do these levels mean? →Frequently Asked Questions
What is High Alert?
High Alert is a brief digital smartphone intervention designed to reduce cannabis-impaired driving among high-risk Canadian youth, developed using the Intervention Mapping framework.
Did the app actually reduce cannabis-impaired driving?
There was preliminary evidence of reduced driving after cannabis co-use compared to the no-contact group, but high attrition and small sample size mean these results need confirmation in a larger trial.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-06246APA
Colonna, Robert; Tucker, Patricia; Mandich, Angela; Alvarez, Liliana. (2025). Using intervention mapping to evaluate 'High-Alert,' a brief smartphone intervention to reduce youth cannabis-impaired driving.. PloS one, 20(8), e0329383. https://doi.org/10.1371/journal.pone.0329383
MLA
Colonna, Robert, et al. "Using intervention mapping to evaluate 'High-Alert,' a brief smartphone intervention to reduce youth cannabis-impaired driving.." PloS one, 2025. https://doi.org/10.1371/journal.pone.0329383
RethinkTHC
RethinkTHC Research Database. "Using intervention mapping to evaluate 'High-Alert,' a brief..." RTHC-06246. Retrieved from https://rethinkthc.com/research/colonna-2025-using-intervention-mapping-to
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.