The relative contributions of parental and sibling substance use to adolescent tobacco, alcohol, and other drug use

While research demonstrates that parental tobacco and alcohol use increases the likelihood of children's substance use, it is unclear whether or not sibling use has a greater, weaker, or similar effect. Based upon self-reported information from Australian adolescents, their siblings and parents, this investigation examines the association between siblings' tobacco and alcohol use. The relationship is consistent, moderately strong, and remains significant when controlling for a number of family-related factors, indicating that the shared environment cannot fully explain the extent of similarity in siblings' behaviors. In addition, sibling substance use has a greater effect on adolescent substance use than does smoking or drinking by parents. These findings indicate the need to include siblings and information regarding sibling relationships in prevention and intervention programs.