University of Washington Sociologist Dr. Abby Fagan studied the contributions and influence of parents, siblings and peers on teen drug use using data from 1,370 Brisbane teenagers, who are a part of one of the world's longest running health studies -- the Mater-University of Queensland Study of Pregnancy.
The Mater Study began in 1981 as a health and social study of 7,223 pregnant women.
The teenagers were interviewed at 14 years old between 1995 and 1997 and were surveyed about how often they drank and smoked and also about their family relationships.
The study's findings included:
- 13 percent of younger siblings reported smoking and 36 percent reported drinking, but rates increased when older siblings also reported substance use.
- 10 percent of younger siblings with non-smoking older siblings used tobacco, compared to 40 percent of those whose older siblings smoked.
- Younger sibling alcohol use increased from 25 to 53 percent when older brothers and sisters reported drinking.
- Maternal depression also had a significant effect on teen substance use.
"If siblings are more powerful role models than parents, however, sibling and their potential influences on each other should be a primary focus of intervention."
Source: Dr. Fagan's paper, co-written with Mater Study founder, Professor Jake Najman, was published in the January 2006 issue of American Journal of Drug Issues.

