Psychiatric disorder involving significant loss of weight. Anorexia is derived from Greek, an: loss or absence, orexia: longing or desire. However, anorexia nervosa is defined on the basis of BODY WEIGHT not loss of APPETITE. The World Health Organization and the American Psychiatric Association agree on the following clinical criteria: maintenance of weight below expected for age and height by 15% or failure to gain weight during a period of growth; self-induced weight loss; body image disturbance in that there is a pathological fear of being or becoming fat; endocrine disorder manifest as AMENORRHOEA (loss of menses) in postmenarchal women or decreased sexual interest and potency in men. The term ANOREXIA NERVOSA was first used by William Gull in 1873, although the first medical description of anorexia nervosa is credited to Richard Morton in 1689, who described two cases of ‘nervous consumption’ in a woman aged 18 and a boy aged 16. Both share with modern accounts significant loss of weight caused by self-starvation in the absence of any primary organic aetiology.
Weight loss is achieved in anorexia nervosa principally by dietary restriction and high levels of exercise. Dietary restriction in anorexia nervosa differs from restrained eating both in the degree and rigidity of restriction imposed (see also RESTRAINED AND UNRESTRAINED EATING). However, some patients with anorexia nervosa also rid themselves of calories using the same purgation methods found in BULIMIA NERVOSA such as self-induced vomiting, fasting, abuse of diuretics and/or laxatives either following binge eating episodes or in the absence of such episodes. Therefore, two main subtypes of anorexia nervosa are recognized—the restricting subtype and the bulimic/purging subtype. Important differences in impulse control, and history of OBESITY are evident between the two subtypes, with the bulimic subtype associated with higher levels of impulsivity, substance abuse, having a higher premorbid weight and family history of obesity. The prognosis of the bulimic/purging subtype is worse than that for the restricting subtype. Anorexia nervosa is characterized by an intense desire to achieve or maintain thinness, to this end, behaviours are focused on losing or maintaining weight. The physical consequences of both the drastic loss of weight and the self-imposed restrictive eating practices are severe. Complications arise in all major organ systems (endocrine, cardiovascular, pulmonary, gastrointestinal, bone, renal, metabolic, haematological, dermatological and neurological). The mortality rate is high in anorexia nervosa—estimated at 18%—and similar to that observed in other psychiatric syndromes such as AFFECTIVE DISORDER and SCHIZOPHRENIA. Anorexia nervosa occurs almost exclusively in developed, industrialized countries and in women (5% of anorexics are male). Diagnoses of anorexia nervosa have been recorded across the lifespan from 7 to 70 years, however, the typical age of onset is adolescence. In the general population, the incidence (new cases) of anorexia nervosa is between 5.0 and 8.1 per 100000 whereas the prevalence (actual number) of anorexia nervosa is estimated at 280 per 100000 of the at-risk population. Certain groups appear to have a higher incidence of anorexia nervosa such as ballet dancers and fashion models.
It is recognized from studies of starvation such as those conducted by Ancel Keys that certain overlapping features exist between the physiological consequences of semi-starvation and psychological features of anorexia nervosa such as intense preoccupation with food and eating. Since a period of dieting generally predates the development of anorexia nervosa, dieting may play a critical role in the onset of anorexia nervosa. However, no single cause of anorexia nervosa has been identified, rather a multifactorial model is generally accepted to account for aetiology. Thus, dieting alongside other precipitating events or experiences may contribute to the development of anorexia nervosa in individuals who are vulnerable (predisposed), but dieting alone is not sufficient to produce the illness. Risk factors that may contribute to the development of anorexia nervosa span individual, family and sociocultural domains. Individual risk factors include genetic predisposition (history of psychiatric illness), stress, low self-esteem, body dissatisfaction, anxiety or feelings of ineffectiveness and physical factors such as the changes experienced during puberty. Family risk factors include history of psychopathology, specific family dynamics and eating disturbances in parents and siblings. The sociocultural climate contributes to the overvalued notion of seeking slimness whilst rejecting and stigmatizing obesity. Factors that contribute to the maintenance of anorexia nervosa include distorted cognitions, low self-esteem, physiological and psychological concomitants of starvation. Therefore, in the multidisciplinary treatment of anorexia nervosa there are two main stages of the therapeutic process. First of all, immediate medical stabilization is necessary using refeeding and pharmacological therapies. In the longer term, objectives such as nutritional management, building self-esteem, and challenging overvalued ideas about thinness are achieved by psychotherapy.
Failure to maintain weight at a normal or expected level characterizes anorexia nervosa. Significant morbidity and mortality are linked to this illness. It is not simply a ‘slimmer’s disease’ but is caused by a myriad of factors. Treatments focus on weight gain, improving self-esteem and body image.
