"Tell Me How Much Your Friends Consume"-Personal, Behavioral, Social, and Attitudinal Factors Associated with Alcohol and Cannabis Use among European School Students.

Background: Substance use in European adolescents remains a serious health concern. Assessing what affects adolescents' substance use is crucial for implementing effective prevention. This study aims to examine alcohol and cannabis use-related behavioral, social, and attitudinal variables that might directly be considered to guide prevention responses for adolescents.