CHAPTER 10 Eating disorders
The eating disorders (apart from obesity, which is considered separately at the end of this chapter) are a group of conditions characterised by an overconcern with size and shape, leading to aberrant eating behaviours and other measures to try to obtain the thin ideal. Although DSM–IVTR and ICD–10 classify eating disorders into distinct conditions, psychopathology may be shared and diagnostic crossover can occur over time. Some authorities classify these disorders within the putative obsessive-compulsive spectrum (see Ch 9). A transdiagnostic approach to classification, which emphasises similarities rather than differences in eating disorders, has also emerged. The classifications according to DSM–IVTR and ICD–10 are summarised in Table 10.1.
TABLE 10.1 Classification of eating disorders
| DSM–IVTR (synopsis) | ICD–10 (synopsis) |
|---|---|
| The classifications are: | The classifications are: |
Anorexia nervosa (AN)
Anorexia nervosa (AN) is a disorder characterised by a distortion of body image such that the individual ‘sees’ themselves as fat when they are in fact thin; they have a ‘morbid fear of fatness’, and engage in activities to try to achieve a thin body ideal. By definition, AN is diagnosed when the individual ‘refuses to maintain a weight over a minimal norm, leading to body weight less than 85% of that expected’ (DSM–IVTR) or is under a body mass index (BMI) of 17.5 kg/m2 (ICD–10) (BMI = weight in kilograms/height in metres2). In growing children, there is a failure to make expected weight gain during a period of growth. In post-pubertal girls, there is the added criterion of amenorrhoea. The criteria are summarised in Table 10.2.
| DSM–IVTR (synopsis) | ICD–10 (synopsis) |
|---|---|
| Criteria are:
• refusal to maintain body weight at or above minimally normal weight for age and height (less than 85% of that expected, or failure of expected weight gain during a period of growth)
|
AN afflicts around 0.5% of young females (it is much less common in males) and onsets usually around puberty (mean age at onset 15–19 years). Patients engage in dieting behaviours, with either a purely restrictive pattern (i.e. restricting intake, especially of what are perceived of as fattening foods), or encompassing binge–purge cycles, with episodic overeating followed by guilt, self-blame and purging. Dieting becomes an obsession, with avoidance of foods perceived of as fattening (some patients will avoid even smelling or touching such foods), calorie-counting, excessive weighing, and so forth. A variety of ritualised behaviours can occur, including around food preparation and meals, excessive exercise and weighing. Patients might also employ laxatives and diuretics. Box 10.1 lists some of the medical complications associated with AN.
restoration to healthy weight (menstruation and ovulation in females, normal sexual hormone levels in males and restoration of physical and sexual growth and development in children and adolescents)
