A pilot study of the acceptability, efficacy, and iatrogenic effects of a brief dynamic norms intervention for reducing young adult alcohol use

Background: Alcohol use and its related consequences are a public health problem among young adults. Building upon efficacious personalized normative feedback interventions, dynamic norms can be used to highlight the decreasing prevalence of alcohol use over time among young adults' peers, thereby increasing their motivation to change drinking consistent with the trend. Because limited research has examined dynamic norms feedback interventions for alcohol use, we examined the acceptability and initial efficacy of such an intervention, and potential iatrogenic effects of showing norms feedback about drinking to light drinkers and nondrinkers.

Methods: Participants were 546 unvaccinated young adults ages 18-24 who completed a baseline survey, intervention, and 1-month follow-up assessment. Participants were block randomized to receive a brief web-based dynamic norms intervention, with feedback content focused on either (a) alcohol-related behaviors (intervention) or (b) COVID-19 vaccine behaviors (the attention-matched control for the present study).

Results: On average, participants who received the alcohol intervention rated it as generally engaging, helpful, and acceptable, with the majority (90.8%) indicating that they would recommend it to a friend. Supporting initial efficacy, in generalized linear models controlling for demographics and baseline alcohol outcomes, at 1-month follow-up the alcohol intervention was associated with statistically and clinically significant reductions in all indices of perceived drinking norms, drinking quantity, drinking frequency, and driving after drinking occasions. Lighter drinkers showed no adverse iatrogenic effects.

Conclusions: Presenting alcohol-related personalized normative feedback using dynamic trends is a promising intervention for reducing alcohol use in a community sample of young adults. Further research clarifying the optimal presentation of dynamic norms is needed.