Environment is important in determining if girls and young women begin to drink, but it is the genes, which determine if she turns into an alcoholic, researchers at Washington University School of Medicine in St. Louis have found.
The findings are based on a study, in which researchers examined 3,546 female twins ages 18 to 29 to find out the influences of genes and environment in the development of alcohol dependence.
The way to alcohol dependence involves transitions through many stages of drinking behaviours.
The stages start from the first drink to the first alcohol-related problems, such as drinking and driving, difficulty at school or work related to alcohol use, to alcohol dependence.
Environmental factors that the twins shared, such as exposure to conflict between parents or alcohol use among peers in school, exerted the largest influence on initiation of alcohol use.
Researchers found that women who had their first drink at a young age were at a higher risk of developing serious alcohol problems.
They found that all transitions were attributable in part to genetic factors, increasing from 30 percent for the timing of first drink to 47 percent for the speed at which women progressed from problem drinking to alcohol dependence.
However, genetics did not explain everything.
"Even when genetic factors are most influential, they account for less than half of the influence on drinking behaviour," says lead author Carolyn E. Sartor, Ph.D., a postdoctoral research fellow at the School of Medicine.
"That's good news in terms of modifying these behaviours and reducing the risk of developing alcohol dependence. Genetics are not destiny, and our findings suggest that there are opportunities to intervene at all stages of alcohol use," Sartor added.
The study is published in the April issue of Alcoholism: Clinical and Experimental Research.