Eating Disorders

Eating Disorders

Introduction:

Anorexia nervosa was first described by William Gull in 1868 and is characterized by deliberate and extreme weight loss. In bulimia nervosa, episodes of overeating are followed by self-induced vomiting. There is considerable overlap between these two eating disorders.

1. Anorexia Nervosa:

Concerns about weight, and dieting in order to lose weight are extremely common in the general population, particularly among young women. Anorexia nervosa represents an extreme form of this behavior. Fear of being fat leads to the adoption of a starvation diet. Weight falls to at least 15% below normal, so that the body mass index (BMI) is 17.5 or less. Despite this, anorexics continue to believe they are overweight, even when faced with their emaciated reflection in the mirror. This distorted body image drives them to continue to lose weight, and they may adopt other methods such as excessive exercise, self induced vomiting or abuse of laxatives, diuretics or appetite suppressants such as amphetamine. They may become preoccupied with food, hoarding it, or becoming very interested on cookery, creating elaborate meals for their family while still refusing to eat. Amenorrhea occurs in the early stages of weight loss and is an indication of a widespread endocrine disorder. Table 1 shows the signs and symptoms found in anorexia nervosa.  

2. Bulimia Nervosa:

In bulimia nervosa there is also a fear of fatness, but the characteristics symptom is binge eating. ‘Binges' are the consumption of huge quantities of food at a single sitting, particularly carbohydrate-rich items such as biscuits, cakes and bread. They often take place in secret, and away from meal times. Some bulimics will eat normally at other times, although calorie-controlled diets are common. A small number also have anorexia nervosa. In bulimia nervosa, binges provoke feelings of guilt and disgust and a sense of being out of control. These feelings lead to a desire to get rid of the food, usually achieved by putting fingers down the throat to induce vomiting. Many bulimics are eventually able to spontaneously vomit. As in anorexia, laxative and diuretic abuse may be further threats to health. Despite a dread of weight gain, many maintain a normal weight and may even be overweight. Menstruation is often normal.

Epidemiology

Bulimia is more common than anorexia nervosa. Anorexia nervosa usually starts is adolescence, and bulimia a few years later. Surveys of young women have found a prevalence of 13% for bulimia and 1 to 2% for anorexia nervosa. Both are much more common in women than men. Occupations that depend upon keeping a low body weight, such as ballet dancing and modelling, have a particularly high risk of anorexia.

Aetiology

The aetiology for both anorexia nervosa and bulimia nervosa is similar. There are many factors thought to be important and most cases will be due to a combination of causes.

Predisposing factors

• Cultural factors. Anorexia nervosa and bulimia nervosa are disorders of the food-rich developed world.
  Western society has developed a stereotyped view of physical attractiveness which equates ‘thin' with ‘beautiful', and promotes negative attitudes about obesity. The media bombards us with idealised images of underweight models alongside advertisements for confectionery. Adolescents are particularly vulnerable to these cultural pressures to conform and to be attractive.
• Genetic factors. Twin studies have shown that genetic factors do play a role, probably by creating a vulnerability to weight loss so that in the presence of environmental pressures an eating disorder may develop.
• Hypothalamic dysfunction. The hypothalamic area of the brain controls feeding behaviour, temperature regulation and fluid balance. There are marked changes in the functioning of the endocrine system in anorexia (Table 1.). In the main these changes are secondary to the weight loss, but the early onset of amenorrhoea in some anorexic women suggests that some changes may be primary.      

 Table 1. (below) Signs and symptoms of anorexia nervosa.

Endocrine

• á Growth hormone, á Cortisol, â Gonadotrophin, â T3

Cardiovascular

• Bradycardia, Hypotension

Constipation

Amenorrheo

Lanugo hair on body

Sensitivity to cold

Muscle weakness

Oedema

Psychological

• Fear of fatness, preoccupation with food,
• Distorted body image

Precipitating and maintaining factors

• Family issues. Preparing and sharing food plays an important role in family relationships. The conflicts that often arise between adolescents ant their parents can be acted out at meal times, with refusal to eat becoming an act of rebellion. There is often some abnormality in family relationships, although the problems may be a result of the eating disorder, rather than the cause of it. It is common for the mother to have some concerns about weight and dieting, and in some cases to also have an eating disorder.
• Psychological issues. Adolescence may be a time of conflict with parents or others. Feelings of having little control over events, lack of confidence and poor self image are common. In some cases anorexia nervosa can be a way of coping with some of these psychological pressures, by creating an illusion of being in control. Another theory is that the amenorrhoea and arrested physical development of anorexia nervosa fulfils a wish to escape the problems of adolescence and avoid adulthood. Parents who do not want their little girl to grow into a woman and leave home may collude in this illusion of prolonged childhood.

Management

Patients with eating disorders are often very reluctant to accept that they are ill, and have the realistic fear that the main aim of treatment will be weight gain. Therefore the first challenge in managing eating disorders is engaging the patient in treatment. It may take many hours over several appointments to gain the patient's trust, complete an assessment and built a therapeutic relationship that will allow change to begin to happen.

Assessment begins with a full psychiatric history and mental state examination. An informant from the family can often provide valuable information, but can only be contacted with the consent of the patient. The main psychiatric differential diagnosis to consider is depressive disorder. A detailed physical examination is important, looking for evidence of malnutrition and effects of repeated vomiting. Physical illnesses that present with weight loss must be excluded, in particular chronic debilitating diseases, malabsorption syndromes and thyrotoxicosis. Investigations may include full blood count, urea and electrolytes, creatinine, liver function tests, ECG and chest X-ray.

The aim of any treatment programme must be to return to a healthy weight, and stop binges and weight control measures that threaten health. It is helpful to work towards a realistic target weight that is reached through negotiation with the patient. Psychological, physical and social treatments should be considered.

1. Psychological treatment

•     I.        Cognitive therapy: This has been shown to be successful in research studies. It aims to examine and change thought processes underlying the abnormal behaviour. Therapy may include keeping a diary, for example recording binges or vomiting and the thoughts and feelings that occur before, during and after this behaviour. The diary is used in therapy sessions for the patient and therapist to work together to find a strategy to change the behaviour.

•   II.        Behavioural therapy: This depends upon the patient learning new behaviours through a system or rewards and positive feedback. Targets which are realistic and achievable are set. A plan for achieving the target is discussed, and progress is monitored. Success is rewarded with praise, and the patient gains confidence from her successes. As each target is achieved a new one is set.

•  III.        Family therapy: This may be the treatment of choice if abnormal family relationships are thought to have a role in the eating disorder. There are many different models of family therapy. In most cases two therapists work together with the family. The family as a whole is seen as the source of the problems rather than the individual with the eating disorder, and it is acknowledged all members of the family will be acted out in the therapy sessions, giving the family an opportunity to understand the way the family functions and make changes.

2. Physical treatment

There is only a limited role for drug treatment in the management of eating disorders. Fluoxetine, a specific serotonin reuptake inhibitor (SSRI) which is usually used in the treatment of depression, is also used in bulimia to suppress the appetite and limit bingeing. It is not an adequate treatment for bulimia in itself and must be used alongside psychological therapist.

3. Social treatment  

Some patients will require social interventions, in particular help to gain confidence and independence. Social and self-help groups, advice about housing and finances and occupational therapy may be useful.

4. Hospital treatment

The majority of anorexic and bulimic patients can be managed as outpatients. However, if the weight falls to a dangerously level, admission may be become necessary, ideally to the shared care of both a psychiatrist and physician. Weight gain is achieved with a diet of regular meals, supplements if necessary with high calorie drinks and snacks. The nursing staff have an important but difficult role in management. They must strike a balance between building a trusting relationship with the patient and adopting a monitoring role, supervising and meal times, ensuring there is no self-induced vomiting and recording weight gain.

Course and Prognosis       

The course of eating disorders trends to be variable and fluctuating. In general about 65% have a good outcome and maintain normal weight, 20% remain moderately underweight long term and 15% have a poor outcome, with persisting seriously low weight. Poor outcome is associated with very early or late onset of illness, a chronic course, severe weight loss, coexisting anorexia and bulimia and persisting relationship difficulties.  Men generally have a worse prognosis.

References:

1. Stevens L, Rodin. Psychiatry: An illustrated colour text, Churchill Livingstone 2001

2. Steple D. Oxford Handbook of Psychiatry, Oxford University Press, 2006