Text-Message Cannabis Treatment Moved Young Adults to Action Stage, Cutting Use by 50% | Research

The takeaway

Young adults receiving a text-message motivational interviewing treatment who advanced to the action/maintenance stage of change had 50% lower odds of high THC levels and used cannabis 4 fewer days per month at 6-month follow-up.

Young adults wanting to reduce cannabis use and clinicians seeking scalable CUD treatment approaches.

50% lower odds of high THC levels at 6 months

What the researchers found

Mediation analysis showed that PNC-txt participants who reached the Action/Maintenance stage by 1 month had 50% lower odds of the highest THC metabolite level (300 ng/ml) and reported 4 fewer days of cannabis use in the past 30 days at 6 months, compared to controls.

Why it matters

Cannabis use disorder treatment has historically struggled with engagement, especially among young adults. A text-message approach overcomes key barriers (stigma, scheduling, cost) and this study shows it works through a well-established clinical mechanism, the Stages of Change.

The numbers in context

N = 1,078 young adults. 4-week PNC-txt intervention. Action/Maintenance stage at 1 month: 50% lower odds of 300 ng/ml THC test. 4 fewer cannabis use days at 6 months. Biological (urine) and self-report outcomes both confirmed effects.

How the study worked

Two-arm RCT with 1,078 US young adults randomized to 4 weeks of PNC-txt (text-message motivational interviewing) or wait-list control, followed for 6 months. Urine drug tests and self-reported use were outcome measures. The Marijuana Ladder assessed stages of change, dichotomized as Cognitive (precontemplation/contemplation/preparation) vs. Behavioral (action/maintenance) stages.

What this study cannot tell us

Wait-list control means participants knew their group assignment. The mediation analysis is exploratory. Not all participants provided urine samples at all time points. The treatment effect operates through motivation change, so participants not ready to change may not benefit.

How to read the evidence

Large RCT with biological outcome confirmation and established mediator. Moderate-strong evidence, though wait-list control and mediation design introduce some limitations.

When this study was published

Published in 2025.

The bigger picture

This is one of the largest CUD treatment trials ever conducted and one of the first to validate text-based delivery with biological outcomes. The combination of biological confirmation (urine THC) with the behavioral mechanism (stages of change) strengthens the evidence considerably.

Questions still open

Could this approach be scaled through healthcare apps or integrated into primary care? Would adding pharmacotherapy enhance the text-message treatment effects?

Common questions

How does a text-message treatment work for cannabis?

PNC-txt delivers motivational interviewing content via text messages over 4 weeks. It helps users examine their reasons for use, build motivation to change, and develop strategies for reducing use, all through their phone.

Do you have to want to quit for this to work?

The treatment works by moving people through stages of readiness. You do not have to start in the "action" stage, but the treatment helps you get there. Those who reached action/maintenance showed the best outcomes.

Read the original research

Young Adults Advancing Through the Stages of Change: A Mediational Analysis of Cannabis Use Disorder Treatment.

Substance use & misuse, 60(10), 1523-1529

View on PubMed ↗Publisher’s paper ↗

Citation

Mason, Michael J; Coatsworth, J Douglas; Russell, Michael A; Mennis, Jeremy; Riggs, Nathaniel R; Zaharakis, Nikola; Brown, Aaron. (2025). Young Adults Advancing Through the Stages of Change: A Mediational Analysis of Cannabis Use Disorder Treatment.. Substance use & misuse, 60(10), 1523-1529. https://doi.org/10.1080/10826084.2025.2505767