Collective name for psychiatric syndromes involving BODY WEIGHT and eating disorders. Eating disorders might vary from the loss of appetite observed in cancer ANOREXIA to HYPERPHAGIA observed in PRADER-WILLI SYNDROME. However, the term eating disorder is normally restricted to the specific clinical syndromes of ANOREXIA NERVOSA, BULIMIA NERVOSA and BINGE EATING disorder. Central to anorexia and bulimia nervosa is the overvalued idea of becoming or staying slim. To achieve their goal, eating-disordered individuals engage in a range of behaviours from self-starvation and dietary restriction to episodes of overeating followed by compensatory behaviour such as vomiting, fasting or abuse of diuretics and/or laxatives.
The names ‘anorexia’ and ‘bulimia’ are problematic since there may be no loss of APPETITE nor excessive appetite as implied by the literal meanings of the terms. The label ‘nervosa’ closely follows early descriptions of hysteria in women and thus is also problematic since this discourse sought to link mental illness to women’s reproductive HORMONES. It is argued that eating disorders are highly specific to women because women in Western societies experience conflict around food. Women are socialized to nurture and nourish others but experience pressure to attain a slender ideal by forsaking such nourishment for themselves. Feminist theories explore the relationship between women’s lack of power and low status in our society as critical in the development of eating disorders.
Anorexia nervosa is diagnosed following relative weight loss, loss of menses, fear of being fat despite obvious emaciation and disturbed BODY IMAGE. Bulimia nervosa is diagnosed not on the basis of body weight, but on the loss of control of eating, fear of being fat, and repeated episodes of overeating coupled with attempts to get rid of the energy consumed (vomiting, dieting, excessive intake of laxatives/diuretics, fasting, exercise). Both anorexia and bulimia nervosa are characterized by a pathological fear of fatness, thus the central feature of these disorders is not disordered appetite, but rather overvalued ideas about weight and shape. In contrast to this, binge eating disorder does not share the central feature of a fear of being fat and no attempts are made to compensate for overeating. Rather the suggested diagnosis of binge eating disorder depends upon repeated episodes of binge eating characterised by loss of control and eating an objectively large amount of food in a discrete period; experiencing distress following binge eating; and at least three of the following—rapid eating, eating beyond normal comfort, eating when not hungry, eating alone due to embarrassment and feeling disgust, depression or guilt after overeating. Binge eating disorder may be diagnosed in obese and non-obese (see OBESITY) individuals. However, binge eating disorder is in the early stages of investigation and is at present not a fully recognized eating disorder.
The physiological and behavioural consequences of semi-starvation have been elucidated in a classic studies by Keys and his colleagues who placed young, healthy normal weight men on a diet for 6 months to achieve a 25% loss of body weight. These men developed some of the characteristics of eating disorders. For example, the participants became obsessed with food, some started to collect recipes and to dream about food. Some men binged on food and others reported overwhelming HUNGER sensations. The men became more depressed, lost their ability to concentrate, experienced a reduced SEXUAL AROUSAL and lost interest in their daily activities. Thus, semi-starvation causes changes in cognitive and emotional well-being which may contribute to and exacerbate the development of an eating disorder. Eating disorders are mediated by a variety of predisposing, precipitating and perpetuating events, which might differ considerably from individual to individual. However, predisposing factors (variables which make someone vulnerable to developing an eating disorder) might include societal pressures, family dynamics and eating practices, individual vulnerability and history of individual and family psychiatric illness; precipitating factors (which trigger an eating disorder) might include stress, anxiety, low self-esteem; and perpetuating factors (which maintain the eating disorder) might include semi-starvation resulting from extreme dieting and weight loss; physiological and psychological responses to restriction, bingeing and purging. Multidisciplinary treatment programmes generally include a variety of individual and group psychotherapies, pharmacotherapy, nutritional counselling and psychoeducation. Pharmacological treatments for eating disorders include tricyclic ANTIDEPRESSANTS, ANXIOLYTICS and appetite suppressants (fluoxetine, for example) or appetite enhancers (such as cyproheptadine). Reports suggest that eating disorders are increasing. However, it is difficult to ascertain the degree of increase, given a greater awareness among general practitioners and the general public.
Anorexia and bulimia nervosa are two examples of eating disorders. Both involve an overconcern about weight and shape and behaviours which aim to reduce or maintain body weight. Eating disorders are typically preceded by dieting; however, this is not sufficient on its own to cause eating disorders. A new form of eating disorder named binge eating disorder is currently under investigation. Treatments for eating disorders focus on achieving and maintaining normal weight and rejecting overvalued notions of thinness.
