Among 8594 adolescent and young adult females throughout the United States, eating disorders were common and associated with an increased risk of developing a variety of adverse outcomes. Approximately 4.1% developed PD, 4.1% developed BED, and 1.5% developed BN. However, if we adhere to the current diagnostic criteria of the DSM-IV, which do not consider PD or BED as distinct eating disorders, we would have only identified <2% of females as having an eating disorder. The underestimation is even more striking if we include EDNOS, which increases the prevalence of eating disorders to 13% to 21% among adolescent and young adult females.
BED is expected to be included as a recognized eating disorder in DSM-5; however, PD will be just 1 of several different types of eating disorders not elsewhere classified. The argument against including PD as a distinct category is that there are insufficient data on its prevalence, correlates, consequences, and treatment. Our data would suggest that the current plans for DSM-5 will result in a large underestimation of the true prevalence of eating disorders, albeit less of an underestimation than DSM-IV. Moreover, the increases in risk of developing psychopathology are similar for those with PD and BN, suggesting that it might be prudent to classify individuals into having disorders involving purging (ie, BN and PD) and those with disorders that only involve binge eating (ie, BED).
Treatment success is only moderate,31
and the health consequences of eating disorders are numerous32
; thus, prevention is essential. Although Stice et al14
found that among 496 adolescent girls, those with full or subthreshold eating disorders had more impairment and distress than their peers, to the best of our knowledge this is the first article to examine prospectively whether full and subthreshold eating disorders are predictive of a range of specific adverse mental and physical health consequences. Our results suggest that primary prevention should focus on prevention of disorders of at least subthreshold severity. Future research should assess whether adolescents who binge and/or purge monthly need or benefit from treatment. Because treatment may differ according to severity of the disorder, a staging approach for eating disorders,33
similar to that used to classify hypertension,34
There are several limitations to this study. Our cohort is >90% white, and we relied on self-reports, which may have resulted in some misclassification. However, in a validation study conducted in this cohort, we observed that compared with interviews, self-reported purging had high sensitivity and specificity.23
The strengths of the study far outweigh the limitations. This is the largest longitudinal sample of adolescents and young adults with repeated eating disorder assessments published to date. Information on eating disorders, weight status, and mental health outcomes was collected every 12 to 24 months, and we also had information on a wide range of confounders.
We observed that BED and PD were relatively common among adolescent and young adult females. Not only were these disorders much more common than BN, but they were also associated with a substantially increased risk of numerous adverse outcomes. Thus, there is a need for both BED and PD to be recognized as distinct eating disorders or for PD to be combined with BN, rather than including 1 of these common and serious disorders in the large, heterogeneous, and often overlooked EDNOS group. Moreover, because only a minority of people with a psychiatric illness receive treatment for their disorder,35
and those with BED are particularly unlikely to seek treatment for their eating disorder,11
primary care clinicians need to be made aware of these disorders so that adolescents in need of treatment will be identified.