Study examines prevalence of eating disorders among adolescents

Eating disorders are prevalent in the general U.S. adolescent population and are associated with other psychiatric disorders, role impairment, and suicidality, according to a report posted online today that will appear in the July print issue of Archives of General Psychiatry, one of the JAMA/Archives journals.

Although the lifetime prevalence estimates of eating disorders from population-based studies of adults are relatively low, their severity and dramatic effects have been repeatedly demonstrated through elevated rates of impairment, medical complications, other illnesses, death and suicide, according to background information in the article. Little is known about the prevalence or correlates of these disorders from population-based surveys of adolescents.

Sonja A. Swanson, Sc.M., of the National Institute of Mental Health, Bethesda, Md., and colleagues examined eating disorders with data from the National Comorbidity Survey Replication Adolescent Supplement (NCS-A), a nationally representative sample of U.S. adolescents. The objectives of the study included determining the lifetime and 12-month prevalences of anorexia nervosa (AN), bulimia nervosa (BN), binge-eating disorder (BED) and subthreshold eating disorders; examining their sociodemographic and clinical correlates and patterns of comorbidity with other mental disorders; and to describe the magnitude of role impairment, suicidal behaviour, and service use associated with these disorders. Sufficient information was available to define subthreshold AN (SAN) and subthreshold BED (SBED) among those youths who did not meet criteria for AN, BN, or BED. The sample included face-to-face interviews with 10,123 adolescents ages 13 to 18 years.

The researchers found that lifetime prevalence rates of AN, BN, BED, SAN, and SBED were 0.3 percent, 0.9 percent, 1.6 percent, 0.8 percent, and 2.5 percent, respectively; and the 12-month prevalence rates of AN, BN, BED, and SBED were 0.2 percent, 0.6 percent, 0.9 percent, and 1.1 percent, respectively. Regarding lifetime prevalence estimates, there were no sex differences in the prevalence of AN or SBED, whereas BN, BED, and SAN were more prevalent in girls.

The majority of respondents with an eating disorder met criteria for at least 1 other lifetime DSM-IV disorder (classification of mental disorders) assessed in this study across the lifetime, with 55.2 percent, 88.0 percent, 83.5 percent, 79.8 percent, and 70.1 percent of adolescents with AN, BN, BED, SAN, and SBED, respectively, endorsing 1 or more co-existing psychiatric disorders. Among adolescents with 12-month AN, BN, BED, and SBED, 97.1 percent, 78.0 percent, 62.6 percent, and 34.6 percent, respectively, reported impairment in the past 12 months; 24.2 percent, 10.7 percent, 8.7 percent, and 2.8 percent, respectively, reported severe impairment. Eating disorders were most strongly associated with social impairment. Nearly all of those with AN (88.9 percent) reported social impairment, and 19.6 percent reported severe social impairment associated with their eating disorder. Lifetime suicidality was associated with all subtypes of eating disorders.

Although the majority of adolescents with an eating disorder sought some form of treatment, only a minority received treatment specifically for their eating or weight problems.

'... this study provides key information concerning the epidemiology of eating disorders in the U.S. adolescent population. The prevalence of these disorders is higher than previously expected in this age range, and the patterns of comorbidity, role impairment, and suicidality indicate that eating disorders represent a major public health concern. Finally, these findings support the nosological distinction [classification of diseases] between the major subtypes of eating disorders as well as the importance of inclusion of the full spectrum of eating behaviours in estimating the magnitude and correlates of eating disorders in the U.S. population,' the authors conclude.