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.

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."

Personal and perceived peer use and attitudes towards the use of nonmedical prescription stimulants to improve academic performance among university students in seven European countries.

BACKGROUND: Overestimations of non-prescribed stimulant use of peers are well documented in the USA and have also been identified as predictive of personal stimulant consumption. This study aimed to examine whether overestimations of peer use and approval of the use are associated with personal use and attitude towards the use of non-prescribed stimulants among European university students. METHOD: The EU funded 'Social Norms Intervention for the prevention of Polydrug usE (SNIPE)' study was conducted in seven European countries. In a web-based questionnaire, 4482 students were asked about their personal use and their attitude towards non-prescribed stimulant use, as well as the perceived peer use and peer attitude. RESULTS: 59% of students thought that the majority of their peers used non-prescribed stimulants more frequently than themselves, and only 4% thought that the use of the majority was lower than their personal use. The perception that the majority of peers had used non-prescribed stimulants at least once was significantly associated with higher odds for personal use of non-prescribed stimulants (OR: 3.30, 95% CI: 2.32-4.71). In addition, the perception that the majority of peers approved of the non-prescribed use of stimulants was associated with a 4.03 (95% CI: 3.35-4.84) times higher likelihood for personal approval. DISCUSSION: European university students generally perceived the non-prescribed use of stimulants of peers to be higher than their personal use. This perception, as well as a perception of higher approval in the peer group, was associated with a higher likelihood of personal non-prescribed stimulant medication use and approval.

Illicit substance use among university students from seven European countries: a comparison of personal and perceived peer use and attitudes towards illicit substance use.

OBJECTIVE: To compare European students' personal use and approval of illicit substance use with their perceptions of peer behaviours and attitudes, and investigate whether perceptions of peer norms are associated with personal use of illicit substances and attitudes. METHOD: This study used baseline data from the Social Norms Intervention for the prevention of Polydrug usE (SNIPE) project involving 4482 students from seven European countries in 2012. Students completed an online survey which included questions on personal and perceived peer illicit substance use and personal and perceived peer attitude towards illicit substances. RESULTS: 8.3% of students reported having used illicit substances at least once in their life. 49.7% of students perceived that the majority of their peers have used illicit substances more frequently than themselves. The perception was significantly associated with higher odds for personal illicit substance use (OR: 1.97, 95% CI: 1.53-2.54). The perception that the majority of peers approve illicit substance use was significantly associated with higher odds for personal approval of illicit substance use (OR: 3.47, 95% CI: 2.73-4.41). CONCLUSION: Students commonly perceived that their peers used illicit subtances more often than themselves. We found an association between the perceived peer norms/attitudes and reported individual behaviour/attitudes.