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The eating disorders, including anorexia nervosa and bulimia nervosa, continue to receive appreciable clinical and research attention, paralleling an increase in their prevalence over the past few decades. Disturbances in eating behavior are, of course, not new. Historical documentation of anorexia nervosa dates back to the early Christian saints. Binging and purging, although distinct from our current concept of bulimia nervosa, took place in the lives of ancient Romans.
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The eating disorders are best viewed as clinical syndromes rather than specific diseases, as they do not result from a single cause or follow a single course. As psychiatric syndromes, they are defined largely by a constellation of behaviors and attitudes that persist over time and have characteristic complications contributing to physical and psychosocial dysfunction. Because of the complexity and breadth of contributing factors, as well as the extent of comorbid psychopathology, knowledge of the behavioral characteristics of the eating disorders can lead to improved recognition and implementation of effective treatment strategies. In light of the complicated interplay of psychiatric, psychosocial, and medical consequences, treatment beyond initial medical stabilization generally requires referral to specialists. Importantly, though, the primary care physician is in a position to identify at-risk behaviors that may contribute to the development of eating disorders, particularly in adolescent and young adult females.
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MULTIDIMENSIONAL MODEL
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A comprehensive multidimensional model best illustrates the role various factors play in the genesis of clinically significant eating disturbances. In this schema, also referred to as a stress–diathesis model, psychological, biological, and sociocultural stressors contribute to the development of the syndrome (see Chapter 34).
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Psychological factors include personality features, such as the anorectic’s obsessive-compulsive qualities, constrained affect, and sense of ineffectiveness, and the bulimic’s impulsivity. They also include the influence of developmental stressors and family dynamics. Body dissatisfaction, combined with other psychological, behavioral (in particular, dieting), or biological vulnerabilities, appears to be an important contributor and may identify those at greater risk.
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Biological factors are most often due to the adverse effects of starvation, malnutrition, and purging behaviors, including vomiting and the misuse of laxatives and diuretics. Restrictive dieting and subsequent malnourishment may contribute to the development or exacerbation of comorbid psychiatric conditions, such as anxiety and depression. In addition, a preexisting biological vulnerability is supported by neurophysiologic investigations showing dysfunction of serotonin, dopamine, and norepinephrine neuromodulator systems; a small number of patients with anorexia develop amenorrhea preceding significant weight loss suggestive of hypothalamic dysregulation. The additional contribution of components of the peripheral satiety network is being elucidated. Genetic findings are suggestive and support evidence of substantial hereditability, but require further investigation given the complexity of these conditions.
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Sociocultural factors figure prominently in the etiology of the eating disorders. The idealization of thinness contributes to dieting behavior, often beginning in early adolescence. Of note, dieting is almost always present as a precipitant to the development ...