JMIR Publications

ABSTRACT

Background:

Excessive alcohol consumption among adolescents and young adults is a serious health problem. Dynamically tailored interventions could support them in reducing excessive drinking. We therefore developed ‘WhatDoYouDrink’ (WDYD), a 17-week dynamically tailored mHealth intervention providing personalized support on alcohol consumption.

Objective:

To evaluate the effectiveness, acceptability and use of WDYD in reducing alcohol consumption of adolescents and young adults at risk.

Methods:

We conducted a two-arm, parallel-group randomized controlled trial (RCT) using Ecological Momentary Assessments (EMA). Participants were recruited via an educational alcohol program, an online lifestyle monitor, adds on social media or news items on websites. Participants downloaded the standalone WDYD app, and when having given active informed consent were randomized to the intervention or control group. Participants in the intervention group received dynamically tailored feedback sessions on alcohol consumption (weeks 0–5, 7, 9, 13, and 17) and goal-monitoring reminders. Both groups completed an online baseline survey, two follow-up surveys (weeks 9 and 33), and various EMAs (seven daily assessments during weeks 1, 7, 13, 19, 25, 31, and 33). Treatment assignment was not blinded; participants were informed about both groups during consent and may have become aware of their group allocation after randomization. Primary outcomes were excessive drinking, binge drinking and weekly alcohol consumption. Secondary outcomes were intrinsic motivation, self-confidence and mood. Acceptability of WDYD was measured by survey questions; use was tracked via app data logs. Multilevel generalized linear regression models in R with multiple imputation were used to assess effects.

Results:

Analyses were based on data from 1,767 participants; 720 in the intervention group and 1,047 participants in the control group. Almost half of the participants were female (47.5%), and most (72.%) were aged 18-24 years (median = 19.40 years). The dropout rate was high; up to 96.0% in the final 33rd week. No significant effect of WDYD were found on primary outcomes and mood, except for week 1 (Excessive drinking: B=-0.35, SE=0.15; 95%CI=-0.64 to -0.05; Binge drinking: B=-0.36, SE=0.16; 95%CI=-0.68 to -0.04; Mood: B=0.20, SE=0.06, 95%CI=0.08-0.32). Both groups reduced their alcohol consumption over time. Significant positive effects were found for intrinsic motivation and self-confidence up to 25 weeks (week 25: B=0.54, SE=0.24; 95%CI=0.06 to 1.02 for motivation; B=0.72, SE=0.26; 95%CI=0.22 to 1.23 for self-confidence). Participants evaluated WDYD as acceptable and usable.

Conclusions:

WDYD did not significantly reduce excessive drinking compared to control, but improved motivation and self-confidence. High dropout rates highlight challenges in sustaining engagement in long-term mHealth interventions. Future research should explore strategies to enhance retention and optimize dynamic tailoring. Clinical Trial: Onderzoekmetmensen.nl Trial 28135; https://onderzoekmetmensen.nl/nl/trial/28135