As noted earlier, binge-eating disorder is a proposed diagnos-tic category related to, but quite distinct from, bulimia nervosa. Individuals with binge-eating disorder, like individuals with bulimia nervosa, repeatedly engage in episodes of binge-eating but, unlike patients with bulimia nervosa, do not regularly utilize inappropriate compensatory behaviors. Binge-eating disorder has been the focus of sustained attention only in the last decade. The clinical utility of the information which quickly developed following the recognition of bulimia in the DSM nomenclature was an important source of interest in binge-eating disorder.
Suggested diagnostic criteria for binge-eating disorder are in-cluded in an appendix of DSM-IV-TR which provides criteria sets for further study. These criteria require recurrent episodes of binge-eating, which are defined just as for bulimia nervosa. The major difference from bulimia nervosa is that individuals with binge-eating disorder do not regularly use inappropriate compensatory behavior, although the precise meaning of “regu-larly” is not specified. Other differences from the definition of bulimia nervosa relate to the frequency of binge-eating: individu-als with bulimia nervosa must binge-eat, on average, at least two times per week over the last 3 months, whereas individuals with binge-eating disorder must binge-eat at least 2 days per week over the last 6 months. A major reason for the difference in the criteria is that the end of a binge episode in bulimia nervosa is usually clearly marked by the occurrence of inappropriate compensatory behavior, like purging, whereas in binge-eating disorder, the end of a binge episode may be more difficult to identify precisely. The criteria attempt to deal with this definitional difficulty by requir-ing the frequency of binge-eating to be measured in terms of the number of days per week on which episodes occur and, because of the potential difficulty in distinguishing “normal” overeating from binge-eating, to require a 6 month duration, rather than 3 months for bulimia nervosa. In addition, the suggested DSM-IV-TR cri-teria for binge-eating disorder require that individuals report be-havioral evidence of a sense of loss of control over eating, such as eating large amounts of food when not physically hungry. Finally, while there is some evidence that individuals with binge-eating disorder tend to be more concerned about body image than in-dividuals of similar weight, the criteria for binge-eating disorder require only that there is marked distress over the binge-eating. Thus, the criteria for binge-eating disorder do not require that self-evaluation be overly influenced by concerns regarding body weight and shape, as is required for bulimia nervosa.
The epidemiology of binge-eating disorder is uncertain. Cross-sectional studies suggest that the prevalence of binge-eating dis-order among adults is a few percent and that the prevalence is higher among obese individuals in the community and among obese individuals who attend weight loss clinics. Similarly, the frequency of binge-eating disorder increases with the degree of obesity. In contrast to anorexia nervosa and bulimia nervosa, in-dividuals with binge-eating disorder are more likely to be men (the female to male ratio is roughly 1.5 : 1 compared with approx-imately 10 : 1 for anorexia nervosa and bulimia nervosa), from minority ethnic groups and middle-aged
Very little is known about the etiology of binge-eating disorder. Binge-eating disorder is clearly associated with obesity, but it is uncertain to what degree the binge-eating is a contributor to and to what degree a consequence of, the obesity.
In theory, binge-eating disorder should be easy to recognize on the basis of patient self-report: the individual describes the frequent consumption of large amounts of food in a discrete pe-riod of time about which he or she feels distressed and unable to control. Difficulties arise, however, because of uncertainty about what precisely constitutes a “large amount of food”, especially for an obese individual and regarding what constitutes a discrete period of time. Many individuals describe eating continuously during the day or evening, thereby consuming a large amount of food, but it is not clear whether such behavior is best viewed as binge-eating. Individuals who meet the proposed definition of binge-eating disorder clearly have increased complaints ofdepression and anxiety compared with individuals of similar weight without binge-eating disorder.
The assessment of individuals who may have binge-eating disor-der parallels that of individuals who may have bulimia nervosa. It is important to obtain a clear understanding of daily food intake and of what the individual considers a binge. As in the assess-ment of bulimia nervosa, the interviewer should inquire about the use of purging and other inappropriate weight control methods. Individuals who describe binge-eating disorder are likely to be obese, and it is important to obtain a history of changes in weight and of efforts to lose weight. The interviewer should also inquire about symptoms of mood disturbance and anxiety.
The salient general medical issue is that of obesity. Individuals with binge-eating disorder who are obese should be followed by a primary care physician for assessment and treatment of the complications of obesity. There is no evidence suggesting that the behavioral disturbances characteristic of binge-eating disor-der add to the physical risks of obesity. Whether the presence of binge-eating disorder affects the natural history of obesity is an intriguing but unanswered question.
As noted above, the most difficult issue in the diagnostic assess-ment of binge-eating disorder is determining whether the eating pattern of concern to the individual meets the proposed definition of binge-eating. There are numerous varieties of unhealthy eat-ing, such as the consumption of high fat foods and the nosology of these patterns of eating is poorly worked out.
Some individuals with atypical depression binge-eat when depressed; if the individual meets criteria for both binge-eating disorder and an atypical depression, both diagnoses should be made.
As the recognition of binge-eating disorder is quite recent, there is little definitive information about the natural history of this disorder. However, both controlled treatment studies and follow-up studies of community samples indicate that there is substantial fluctuation over time in the frequency and severity of the cardinal symptoms of this disorder.
For most individuals with binge-eating disorder, there are three related goals. One is behavioral, to cease binge eating. A second focuses on improving symptoms of mood and anxiety disturbance which frequently are associated with binge-eating disorder. The third is weight loss for individuals who are also obese.
Treatment approaches to binge-eating disorder are currently un-der active study. There is good evidence that psychological (e.g CBT) and pharmacological (e.g., SSRI) interventions which are effective for bulimia nervosa are also useful in reducing the binge frequency of individuals with binge-eating disorder and in alleviating mood disturbance. However, it is not clear how helpful these approaches are in facilitating weight loss. Stand-ard behavioral weight loss interventions employing caloric restriction appear useful in helping patients to control binge-eating, but the benefits of such treatment have not been com-pared with those of more psychologically-oriented treatments, such as CBT.