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

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.”

Educational level and alcohol use in adolescence and early adulthood—The role of social causation and health-related selection—The TRAILS Study

“…Peer-led interventions have been shown to reduce adolescent alcohol use [ 68 ]. While less in known about peer-led interventions for young adults, targeting social norms may also be effective in reducing drinking in young adults in college [ 69 , 70 ].…”

Application of behavioral economics for understanding health behaviors among adolescents and young adults

“…For example, in a group of youth were who shown feedback comparing their personal alcohol use to their peers, reductions in perceived peer use led to reductions in drinking [16]. Similar effects were seen in cannabis use, where personalized, normative messaging discouraged cannabis use [17 ▪▪ ,18 ▪ ]. Clinicians can directly apply these study insights to improve their own practice.…”

Neuroscience-informed classification of prevention interventions in substance use disorders: An RDoC-based approach

“…These informative programs increase individuals' selfknowledge and insight and provide scientific evidence for why adolescents are more vulnerable to initiate substance use to reinforce self-agency to regulate their own behaviors. Another group of interventions targeting self-awareness provides feedback and normative information which indicates deviation of one's behavior (i.e., amount of drinking and cannabis use) from the peer norms (Geisner et al, 2007;Larimer & Cronce, 2002;Lee et al, 2010;Pischke et al, 2021b;Riggs et al, 2018) The second category encompasses interventions that teach social skills (e.g., communication skills, developing healthy relationships (Griffin et al, 2006a). Life Skills Training (Griffin et al, 2006b), Unplugged (Faggiano et al, 2010), the Rational Addiction Prevention Program (RAPP) (López-Ramírez et al, 2021), the Climate Schools program (Newton et al, 2022; are some well-known examples of preventive programs developed based on social theoretical models and focus on social competence in adolescents.…”