The Contribution of Genetics to Alcohol Use and Eating-Disorder Symptoms in Girls

Prior research has shown that alcohol use disorders and eating disorders such as bulimia nervosa – binge eating often followed by self-induced vomiting – may have a shared genetic risk. It is unclear, however, whether this risk extends to eating-disorder symptoms other than those associated with bulimia nervosa. This study examined several measures of alcohol use and drive for thinness and body dissatisfaction, which are core eating-disorder symptoms, in adolescent female and male twins.

Participants for the study were from the Swedish Twin Study of Child and Adolescent Development: 219 and 229 male and female identical twin pairs, respectively, and 157 and 175 male and female fraternal twin pairs, respectively. The twins were 16 to 17 years old when their information was collected. The researchers used self-reports to ascertain information about three alcohol use behaviors: any alcohol use during the previous month; having ever been intoxicated; and alcohol-intoxication frequency.  They also used a self-report questionnaire to assess drive for thinness and body dissatisfaction.

The genetic association among alcohol use, drive for thinness, and body dissatisfaction was greater in girls than boys. This contrasts with a previous study by the authors in which they observed a genetic association between alcohol use and symptoms of bulimia in both girls and boys. Therefore, in girls there is genetic overlap between alcohol use and multiple eating disorder symptoms. In contrast, it appears that boys have a more specific and unique association between their alcohol use and bulimic/behavioral eating-disorder symptoms. The authors suggested targeting alcohol use in conjunction with specific eating-disorder symptoms in prevention, intervention, and treatment programs, particularly for females.