Eating disorders are characterised by abnormalities in the pattern of eating, which are mainly determined by the attitude the person takes to their weight and shape.
There are two main types of eating disorder: anorexia nervosa and bulimia nervosa. Obesity is not regarded as a psychiatric disorder, however it can have adverse psychological consequences as well as medical complications.
Many eating disorders go clinically unrecognised and it is estimated that only about half of the cases of anorexia nervosa in the population are detected by primary care. For bulimia nervosa the figure is even lower and many individuals with bulimia remain untreated.
Anorexia nervosa is defined by significant self-induced weight loss as well as a distortion in body image.
The age of onset of anorexia may be anything form 6 to 60 years, but the majority of cases begin between 15 and 19 years of age. It is much more frequent in females than males with the sex ratio being 9:1
Anorexia often begins with ordinary efforts at dieting, which get out of control.
Dieting and weight loss with an intense fear of gaining weight are the main features of the condition.
Girls and women are 10 times more likely than boys and men to suffer from anorexia or bulimia.
The pursuit of thinness may take different forms. Individuals with anorexia will often eat very little. Some will try to achieve weight loss by excessive exercising, misusing laxatives and vomiting.
Individuals with anorexia may have a distorted view of themselves, believing to be too fat when severely underweight.
Many individuals with anorexia nervosa have symptoms that they share with other psychiatric disorders, including poor self esteem, loss of social contact, irritability, mood swings, depressive symptoms and insomnia.
Some of the main physical symptoms of anorexia nervosa are low body weight, increased sensitivity to cold, constipation, dizziness and amenorrhoea.
A preoccupation with eating and a craving for food characterize bulimia nervosa. Over eating binges are followed by self-induced vomiting as a way of controlling body weight. Individuals with bulimia have overvalued ideas about their body shape and their weight. They see themselves as overweight but crave food; so they will binge eat and then make themselves vomit (or use laxatives) to get rid of calories.
Bulimia is more common in women and about 4 out of every 100 women suffer from bulimia at some time in their lives.
Individuals with bulimia have little control over eating. Episodes may be precipitated by stress or by breaking self imposed dietary rules. Overeating often takes place alone. At first it brings relief from tension but relief is soon followed by guilt and disgust. There may be more than one episode of binge eating and purging per day.
Depressive symptoms are more prominent in bulimia nervosa than anorexia nervosa and are probably secondary to the eating disorder.
Repeated vomiting leads to several complications such as weakness, heart problems (arrhythmia) and damage to the kidneys. The teeth become pitted by the acid gastric contents in a characteristic way.
Bulimia nervosa usually begins in late adolescence (often later than anorexia nervosa). It often follows a period of concern about shape and weight. There is usually an initial period of dietary restriction, which after a variable length of time breaks down with increasingly frequent periods of overeating. At some stage self induced vomiting and laxative misuse are adopted to compensate for overeating.
If you are worried you have a problem with eating there are things you can do to help yourself:
Dr Sara Ramirez
Child and Adolescent Psychiatry
Gelber M, Harrison P and Cowen P; 5th edn (2006). Shorter Oxford Textbook of Psychiatry, Oxford University Press
Turk J, Graham P, Verhulst F; 4Th edn (2009) Child and Adolescent Psychiatry, a developmental approach, Oxford University Press
Arrhythmia: alteration in the rhythm of the heartbeat in time or force.