Drug use follows siblings

When it comes to teenage drinking and smoking, siblings are the most influential role models, according to research by the UW's Dr. Abby Fagan.

In a study of 1,370 teenagers in Brisbane, Australia, Fagan and University of Queensland's Jake Rajman found that 13 percent of the teens had tried smoking. The rate jumped to 40 percent, however, when the teenager had an older sibling who smoked.

Fagan and Rajman also found that 36 percent of the teenagers had experimented with alcohol. The number was much higher, 53 percent, when an older sibling drank.

"Most parents think, 'I really have to know who my kid's friends are because they might be the ones trying to get my child involved [with alcohol],'" Fagan said. "But they typically may not be thinking about their own children and that kind of potential peer influence."

Fagan and Rajman looked at teenagers who were part of the Mater-University of Queensland Study of Pregnancy. The study examined health issues in more than 8,500 women and their children. In addition to examining data about obesity and problem behaviors, drug use on an individual level was studied and compared with data of family members.

Both researchers pointed to family history as another factor in teenage drinking and smoking. Looking at substance use as a sole product of peer pressure is not looking at the whole story, said Rajman.

"Such an interpretation is tempered by noting that drug use is likely to have a biological/genetic component and that siblings share similar genetic characteristics," Rajman said.

"If the parent is a smoker it is likely that both kids would become smokers," Fagan said. "That's why they would resemble each other-- because they had the same mom, not because one sibling was influencing the other. So it was important for us to look at that broader family influence as well," he said.

Another factor in teenage substance use is traditional preventative efforts, Fagan wrote in the American Journal of Drug Issues.

Most programs aimed at preventing teenagers from using drugs or alcohol focus on parent-child interactions and adolescent friendships. Instead, Fagan proposes efforts that bring families together in a forum of discussion and learning.

"What some of the more effective programs tend to do is they have parents come to a series of workshops where they really educate them about healthy and effective ways of raising their kids -- how to set limits, how to show affection and how to discipline effectively. What really doesn't happen in most cases is that more than one child is involved in the intervention."

Rajman echoed the idea of group-focused prevention.

"[There is a] need to work with social networks of influence [because] much substance use occurs in these networks," he said. "It is likely to be difficult to persuade youth to change if they remain exposed to their existing networks. Networks should be the focus of strategies of prevention."

Role models are most powerful when they are closer in age to the ones they influence. The teenagers studied had siblings less than three years apart from them in age, a range where influence between brothers and sisters is at its peak.

"Siblings are functioning more like a peer," Fagan said. "And at this stage in development, the younger kids might see their older sibling as a more important role model than their parent just because they identify more with them."