Effects of a Brief Web-Based "Social Norms"-Intervention on Alcohol, Tobacco and Cannabis Use Among German University Students: Results of a Cluster-Controlled Trial Conducted at Eight Universities.

C R Pischke,A Krämer,H Pohlabeln,H Zeeb,M Girbig,S Schneider,R Reintjes,S Muellmann,A Schmidt-Pokrzywniak,A Icks,U Walter,S M Helmer

doi:10.3389/fpubh.2021.659875

Abstract

Background and Aim: “Social norms” (SN)-interventions are aimed at changing existing misperceptions regarding peer substance use by providing feedback on actual norms, thereby affecting personal substance use. It is unknown whether SN-intervention effects previously demonstrated in US students can be replicated in German students. The aim of the INSIST-study was to examine the effects of a web-based SN-intervention on substance use.Design: Cluster-controlled trial.Setting: Eight Universities in Germany.Participants and Measurements: Students were recruited at four intervention vs. four delayed intervention control Universities. 4,463 students completed baseline, 1,255 students (59% female) completed both baseline and 5-months follow-up web-based surveys on personal and perceived peer substance use. Intervention participants received feedback contrasting personal and perceived peer use with previously assessed use and perceptions of same-sex, same-university peers. Intervention effects were assessed via multivariable mixed logistic regression models.Findings: Relative to controls, reception of SN-feedback was associated with higher odds for decreased alcohol use (OR: 1.91, 95% CI 1.42-2.56). This effect was most pronounced in students overestimating peer use at baseline and under or accurately estimating it at follow-up (OR: 6.28, 95% CI 2.00-19.8). The OR was 1.33 (95% CI 0.67-2.65) for decreased cannabis use in students at intervention Universities and was statistically significant at 1.70 (95% CI 1.13-2.55) when contrasting unchanged and decreased with increased use. Regarding tobacco use and episodes of drunkenness, no intervention effects were found.Conclusions: This study was the first cluster-controlled trial suggesting beneficial effects of web-based SN-intervention on alcohol and cannabis use in a large sample of German University students.Clinical Trial Registration: The trial registration number of the INSIST-study is DRKS00007635 at the “German Clinical Trials Register.”

Highlights

It has previously been argued that the University setting is a high-risk environment for substance use due to the opportunity to use [1]
The research questions were (a) whether students participating in the intervention reported lower rates of licit and illicit substance use at follow-up than those not participating in the intervention and (b) whether misperceptions of peer substance use were reduced as a consequence of participating in the intervention
Participation in a web-based personalized normative feedback (PNF) was associated with higher odds for decreased alcohol and cannabis use among students enrolled at intervention compared to delayed intervention control Universities

Summary

INTRODUCTION

It has previously been argued that the University setting is a high-risk environment for substance use due to the opportunity to use [1]. This review included one study conducted in Sweden by Andersson [(27), n = 1.678] examining the effects of different modalities of PNF (and protective behavioral strategies) on peak blood alcohol concentrations Compared to controls, both the interactive voice response (IVR)and the internet-based interventions led to a small but significant overall reduction in peak blood alcohol concentrations at the 6-week follow-up. A Swiss study investigated the longterm efficacy of an internet-based brief intervention, including normative and personalized feedback, for decreasing alcohol use among men assessing the number of drinks consumed per week and the occasions that men engaged in binge drinking [28] They found no differences between the intervention and control group regarding the number of drinks consumed per week and the prevalence of binge drinking at follow-up. The research questions were (a) whether students participating in the intervention reported lower rates of licit and illicit substance use (i.e., alcohol, tobacco, and cannabis consumption, episodes of drunkenness) at follow-up than those not participating in the intervention and (b) whether misperceptions of peer substance use were reduced as a consequence of participating in the intervention

Participants and Procedures

RESULTS

DISCUSSION

DATA AVAILABILITY STATEMENT