Prevalence and Correlates of Eating Disorders in Adolescents

A review of “Swanson, S., Crow, S., Le Grange, D., Swendsen, J., Merikangas, K. (2011).Prevalence and Correlates of Eating Disorders in Adolescents.Archives of General Psychiatry, Online Article, E1-E10.”Walter Kaye, M.D. &Danyale McCurdy, Ph.D.

A new study describes the rates of eating disorders in adolescents. Drs. Swanson, Crow, LeGrange, and Merikangas utilized data from the National Comorbidity Survey Replication Adolescent Supplement, which is a nationally representative sample of 10,123 adolescents ranging from 13- to 18-years-old. Importantly, this survey used face-to-face interviews which are likely to improve the accuracy of making diagnoses.

Five eating disorder diagnoses were ascertained: anorexia nervosa (AN), bulimia nervosa (BN), binge eating disorder (BED), subthreshold AN (SAN), and subthreshold BED (SBED). In general, the findings for the rates over the lifetime of people were similar to past studies. That is, the rates of AN, BN, BED, SAN, and SBED were 0.3%, 0.9%, 1.6%, 0.8%, and 2.5%, respectively. Regarding illness onset, the median ages for onset of AN, BN, BED, and SBED was about 12- to 13-years-old. Eating disorders among adolescents was often associated with functional impairment and suicidality. Most teenagers who had a diagnosis of AN, BN, and BED in the past 12 months reported significant impairment (97%, 78%, and 63%, respectively). In particular, BN and SAN were associated with suicide plans, and BN and BED were associated with suicide attempts.

There were several surprises in this study. There was not a female preponderance in AN and BN. Moreover, AN was only associated with oppositional defiant disorder, not other psychiatric diagnoses. Whether such unusual finding were due to the methods used in the study, or are explained by the young age of the sample, or are due to other factors, remains uncertain.

The majority (73 to 88%) of adolescents with ED reported some contact with service providers, such as mental health specialty care, school services, or general medical services.  However, only a minority (3 to 28%) had specifically talked with a professional about their eating or weight problems. As the authors note, whether this is due to denial, shame or stigma, or a lack of recognition of eating symptoms by professionals treating other targeted problems, it shows that adolescents do use services. This suggests possible avenues for prevention and early intervention if recognition could be improved.

 In summary, not only are eating disorders as prevalent as previously thought, but they are also highly related to significant comorbidity, functional impairment, suicidality, and health service usage. Given the young age of onset, early intervention and prevention is crucial. Furthermore, it appears the gender and ethnicity gap is closing in disordered eating, and prevention programs should also incorporate educational strategies targeting these often underrepresented populations in eating disorder research and treatment studied 1,885 individuals with anorexia nervosa (N=177), bulimia nervosa (N=906), or eating disorder not otherwise specified (N=802) over 8 to 25 years. The investigators used computerized record linkage to the National Death Index, which provides vital status information for the entire United States, including cause of death extracted from death certificates. Crow and colleagues found that crude mortality rates were 4.0% for anorexia nervosa, 3.9% for bulimia nervosa, and 5.2% for eating disorder not otherwise specified. They also found a high suicide rate in bulimia nervosa. The elevated mortality risks for bulimia nervosa and eating disorder not otherwise specified were similar to those for anorexia nervosa.

In summary, these findings underscore the severity and public health significance of all types of eating disorders.