Eating Disorders

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The term eating disorder is used in psychiatry to denote two closely related syndromes, anorexia nervosa and bulimia nervosa (and their variants). The central feature of these disorders is a set of characteristic beliefs and values concerning the pre-eminence of body shape and weight in self-evaluation. These beliefs and values, which are extreme in form, drive much of the disturbed behaviour in people suffering from these disorders, such as the pursuit of thinness in anorexia nervosa and the extreme methods of compensating for overeating in bulimia nervosa.

Anorexia nervosa is a disorder mainly affecting young women in economically developed countries. The typical age of onset is 14 to 16 years, although childhood onset is well recognized and may be increasing (Lask and Bryant-Waugh 1992). The community studies of prevalence suggest that around 1 per cent of the at-risk population (i.e. young women) have the disorder. Case register studies have revealed a marked rise in the number of cases of anorexia nervosa coming to specialist attention. Thus, in Rochester (Minnesota) over the 50-year period from 1935 to 1984 the rate among young women rose from 7.0 to 26.3 per 100,000 person years (Lucas et al. 1991). There is a definite possibility that these findings reflect a true increase in the incidence of the disorder.

Bulimia nervosa was first described as a distinct syndrome in 1979 (Russell 1979). The disorder is almost exclusively found in women with a wide age range affected. The consensus is that 1–2 per cent of young women fulfil strict diagnostic criteria for bulimia nervosa with a greater number suffering from variants of the disorder (Fairburn and Beglin 1991).

People with anorexia nervosa markedly restrict their food intake, typically by adhering to a low carbohydrate diet. There is an associated preoccupation with food and eating. About half alternate between periods of marked restriction and bulimic episodes. Vomiting and laxative abuse are common. People with anorexia nervosa often deny that they have any problems and frequently insist, despite their emaciated state, that they are fat.

The profound weight loss in anorexia nervosa has a number of adverse effects on physical health (Mitchell 1986), such as amenorrhoea, low body temperature, low blood pressure and rapid heart beat. Starvation carries a marked risk of numerous complications including osteoporosis, liver function abnormalities and impaired cardiac function, as well as adverse psychological effects, including concentration impairment, irritability and depression.

The striking clinical feature in bulimia nervosa is the grossly disturbed eating habits, particularly the bulimic episodes. These are episodes of gross overeating which are experienced as occurring outside of voluntary control. They can occur many times a day. Bulimic episodes are fairly uniform in character: the eating is invariably carried out in secret with the food usually eaten quickly with little attention paid to taste; and the food eaten is typically those items the person is at other times attempting to avoid. Body weight tends to remain within the normal range, reflecting a balance between the episodes of overeating and various compensatory behaviours designed to counteract the effects of bulimic episodes. The most common method is self-induced vomiting which frequently terminates bulimic episodes. Purgatives are also used, sometimes in considerable quantities, as is exercise and further efforts at dietary restriction. People with bulimia nervosa have concerns about their body weight and shape similar to those found in people with anorexia nervosa. They tend to overestimate their own body size and persistently feel fat. Symptoms of depression and anxiety are marked in these people, and suicidal ideas and acts not uncommon.

The aetiology of eating disorders is poorly understood, but it is widely accepted that a combination of biological, psychological and social factors are implicated. The relevant aetiological factors can be divided into those which predispose, those which precipitate and those which maintain the disorder.

Being a young woman in an economically developed country is a clear risk factor for eating disorders, presumably because of the social pressures to be slim. Eating disorders run in families. This is consistent with both a genetic and an environmental explanatory account. There is little firm evidence that a particular family environment is pathogenic, but this may be because the critical prospective comparative work has not been conducted. Twin studies suggest a genetic contribution to aetiology. A family history of obesity and of affective disorder have also been found to be important. While childhood sexual abuse is raised in people with eating disorders compared to psychiatrically well controls, the rate is no higher than in those with other psychiatric disorders. Finally, a history of anorexia nervosa is a definite predisposing factor for the development of bulimia nervosa.

The onset of eating disorders is often (though not always) preceded by a significant life event, but there appears to be no specificity in the form of such events. Loss of control over eating of the form seen in bulimia nervosa is almost invariably preceded by a period of dietary restriction. Such dieting itself may be preceded by teasing or adverse comments about the person’s appearance.

Two consequences of weight loss are important in the maintenance of anorexia nervosa. First, the sense of achievement and the associated boost in self-confidence is often a spur to further dieting. Second, when the weight loss is extreme certain starvation effects serve to perpetuate dietary restriction: depressive symptoms lower self-esteem which encourages further dieting; and slow gastric emptying, by heightening the sense of fullness following eating, is a disincentive to eat. In bulimia nervosa the disturbed behaviours and cognitions drive each other in a vicious circle: concerns about weight and shape provoke dieting; dieting leads to lapses and overeating; overeating provokes further concerns about weight and shape and leads to vomiting and further dietary restriction; and this in turn leads to further overeating. This cycle can maintain itself without interruption for many years.

There has been little systematic research into the treatment of anorexia nervosa. The mainstay of treatment has been hospitalization and nursing care, involving the refeeding of patients together with nutritional education in the context of emotional support (Russell 1970). The short-term results of such an approach are good with most patients being restored to a healthy body weight within three or four months. Day-patient treatment programmes have been described and encouraging results reported (Piran and Kaplan 1990). An impressive improvement to the general management of anorexia nervosa has been reported in controlled research by adding family therapy to post-hospital care (Russell et al. 1987).

There has been a considerable amount of controlled research into both the pharmacological and the psychological treatment of bulimia nervosa (Fairburn et al. 1992). It has become clear that, although a modest antibulimic effect is achieved with antidepressant medication, the clinical benefits are generally not maintained with patients relapsing whether or not they persist with the treatment. Far better results have been obtained using psychological treatments. There is some support for the use of a focal psychotherapy, but most of the research concerns the use of cognitive behaviour therapy (Fairburn and Cooper 1989). Excellent results have been found using this treatment with improvements well maintained (Fairburn et al. 1992). This cognitive behaviour therapy for bulimia nervosa has been produced in a self-help format (Cooper 1995) and good results have been reported.

Studies of the outcome of patients with anorexia nervosa have revealed high rates of persisting disturbance (Ratnasuria et al. 1991). The mortality rate appears to be around 15 per cent with the most common cause of death being suicide (Hsu 1990). The outcome of less severe cases of the disorder is unknown but likely to be considerably more favourable.

Few studies of the outcome of bulimia nervosa have been reported. Although there have been no natural history studies it appears that without treatment the disorder runs a chronic course. Follow-up of patients who have received cognitive behaviour therapy has revealed a favourable prognosis for the great majority.

Peter J.Cooper

University of Reading

Cooper, P.J. (1995) Bulimia Nervosa: A Guide to Recovery, London.

Fairburn, C.G. and Beglin, S. (1991) ‘Studies of the epidemiology of bulimia nervosa’, American Journal of Psychiatry 147.

Fairburn, C.G. and Cooper, P.J. (1989) ‘Cognitive behaviour therapy for eating disorders’, in K.Hawton, P Salkovskis, J.Kirk and D.M.Clark (eds) Cognitive-Behavioural Approaches to Adult Psychiatric Disorders: A Practical Guide, Oxford.

Fairburn, C.G., Agras, W.S. and Wilson, G.T. (1992) ‘The research on the treatment of bulimia nervosa’, in G.H. Anderson and S.H.Kennedy (eds) The Biology of Feast and Famine: Relevance to Eating Disorders, New York.

Hsu, L.K. (1990) Eating Disorders, New York.

Lask, B. and Bryant-Waugh, R. (1992) ‘Childhood onset anorexia nervosa and related eating disorders’, Journal of Child Psychology and Psychiatry 3.

Lucas, A.R., Beard, C.M., O’Fallon, W.M. and Kurkland, L.T. (1991) ‘50-year trends in the incidence of anorexia nervosa in Rochester, Minneapolis: a population based study’, American Journal of Psychiatry 148.

Mitchell, J.E. (1986) ‘Anorexia nervosa: medical and physiological aspects’, in K.D.Brownell and J.P.Foreyt (eds) Handbook of Eating Disorders: Physiology, Psychology and Treatment of Obesity, Anorexia and Bulimia, New York.

Piran, N. and Kaplan, A.S. (1990) A Day Hospital Group Treatment Program for Anorexia Nervosa and Bulimia Nervosa, New York.

Ratnasuria, R.H., Eisler, I., Szmukler, G. and Russell, G.F.M. (1991) ‘Anorexia nervosa: outcome and prognostic factors after 20 years’, British Journal of Psychiatry 158.

Russell, G.F.M. (1970) ‘Anorexia nervosa: its identity as an illness and its treatment’, in J.H.Price (ed.) Modern Trends in Psychological Medicine, London.

——(1979) ‘Bulimia nervosa: an ominous variant of anorexia nervosa’, Psychological Medicine 9.

Russell, G.F.M., Szmukler, G., Dare, C. and Eisler, I. (1987) ‘An evaluation of family therapy in anorexia nervosa and bulimia nervosa’, Archives of General Psychiatry 44.

Brownell, K.D. and Foreyt, J.P. (eds) (1986) Handbook of Eating Disorders: Physiology, Psychology and Treatment of Obesity, Anorexia and Bulimia, New York.

Fairburn, C.G. and Wilson, G.T. (eds) (1993) Binge Eating: Nature, Assessment and Treatment, New York.

Hsu, L.K. (1990) Eating Disorders, New York.

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