Eating and Body Weight Anorexia Nervosa

A frequent additional feature is a subjective distortion of body image. Although painfully thin, individuals will insist that they are too fat and/or that their abdomen, buttocks or thighs are too large. Their self-esteem is highly dependent on their body weight and shape they celebrate further weight loss as a laudable achievement. 

The incidence, that is the number of new cases reported per year, ranges from 4.2 per 100,000 women per year in the UK to 12.0 per 100,000 per year in the US. The incidence among 15-24-year-old women appears to have risen since 1974. After the age of 25, the incidence levels off to approximately 5 new cases per 100,000 women per year (Hoek and van Hoeken 2003). 

Anorexia nervosa is much less common in males, the overall prevalence being approximately one tenth to one twentieth of that in females (Lindberg and Hjern 2003). In North America and Western Europe it is also less common among women belonging to ethnic minorities. Among a subset of a national sample surveyed in the US n = 2000) none of the Afro-American women in the sub-sample met criteria for anorexia nervosa compared to 1.5% of the white women (Striegel-Moore et al. 2003). 

Many of the somatic features of anorexia nervosa arise as a result of the severe weight loss following sustained calorie restriction. In addition to amenorrhoea, patients often complain of constipation, and abdominal bloating after food. This latter symptom further discourages eat- 

In addition to the alterations in gonadotrophic hormones described above, patients have an increased plasma cortisol, secondary to an elevation of corticotrophin releasing hormone (CRH) (Putignano et al. 2001). This is a factor in the reduction in bone density and increased liability to fractures seen in anorexia nervosa. Increased CRH inhibits the activity of the orexogenic neuropeptide Y (NPY) thereby further lowering the desire to eat. 

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