INTRODUCTION Anorexia nervosa (AN) and bulimia nervosa (BN) have been the principal eating disorders recognised in psychiatry. They are included in ICD 10. Obesity overshadows both in its public health importance, but has not generally been regarded as a psychiatric disorder. A suggestion of a further eating disorder, binge eating disorder, has recently been made.

It is important to appreciate that AN and BN overlap to some extent, though a diagnosis of AN is held to take precedence over one of BN if they co-exist. In addition, patients may as it were move from AN to BN, and back again, perhaps more than once, though the general trend is for from AN to BN. Perhaps as many as half of those diagnoses with AN eventually settle as BN.

ANOREXIA NERVOSA

Definition Anorexia nervosa, named by Gull in 1874, is characterised by:

• Extreme weight loss (at least 15%) deliberately achieved by dieting and/or other means such as exercise or purgation.
• Amenorrhoea in females, loss of libido in males.
• Abnormal attitudes to food.
• Distorted body image, with a morbid fear of fatness.

Prevalence About 1% of adolescent girls in the UK have the full syndrome, but milder partial versions are common, and prevalence has increased in recent years.

Epidemiology

• Age: most cases start in adolescence, but sometimes onset is before puberty or in adult life.
• Sex: 95% are female.
• Social class: patients tend to come from families in social classes 1 and 2.
• Occupation: occupations which demand a slim figure, for example modeling, beauty therapy and ballet dancing, are over-represented.
• Nationality: the condition mostly affects white subjects living in Western countries. (Indeed, it has been suggested that eating disorders could be seen as a ìculture-boundî syndrome of Western societies).

Causes

• Psychodynamic theories view anorexia nervosa as a means of avoiding maturation, especially in sexual terms; or as a means of acquiring independence, and/or a sense of achievement, through strict control of diet and weight. These attitudes may stem from disturbed family relationships, which are almost always evident in the established case, although they could then be the result of the condition rather than its cause.

• Cultural theories implicate the social and media pressures urging women to be slim and diet-conscious. For example, published fashion photographs are often stretched lengthwise to make the models look even thinner than they really are.

• Hormonal imbalance: hypothalamic dysfunction is always present and is probably secondary to the weight loss.

Clinical Features A decision by a mildly overweight teenager to go on a slimming diet is a common starting-point for this disorder.

• Physical: the patient loses weight by dietary restriction, and sometimes also by self-induced vomiting, taking laxatives or diuretics, and excessive exercising. Amenorrhoea may occur before there has been much loss of weight. Male patients show loss of sexual interest and impotence.

• Mental: the patient is preoccupied with food and weight, takes pride in dieting, and feels guilty about eating more than small amounts. Most patients do not see themselves as unwell or underweight, but feel active, healthy and fashionably slim. In chronic cases greater insight may develop, often resulting in depression.

Differential Diagnosis

• Chronic debilitating physical disease such as cancer, pituitary failure, Addisonís disease, TB or AIDS.

• Psychiatric illness: depression, schizophrenia, obsessive-compulsive disorder.
• Hypothalamic lesions.

Investigations will be sometimes necessary to rule out these conditions; however, there is an important clinical pointer in that there will be no body image disturbance: the patient will not generally have an inappropriate belief of being overweight.

Physical Complications

• Hormonal and biochemical changes:

• CT scan of the brain may show ventricular and sulcal enlargement. These changes are not immediately reversible with weight gain.

• Osteoporotic bones in chronic cases.

Treatment

This is often a chronic relapsing and remitting condition and repeated courses of treatment, including hospital admissions, may be necessary.

• Physical: first priorities are restoration of weight and correction of physical complications. Severe cases require inpatient care, and compulsory treatment under the Mental Health Act 1983 is occasionally indicated. Weight gain is best achieved by winning the patientís agreement to eat more, and skilled nurses can usually manage this, though many patients will be uncooperative at first, secretly disposing of food or vomiting. Some units use a behavioural approach in which privileges like watching TV or having visitors are conditional on regular weight gain, but many patients find this coercive and unhelpful.

• Drug treatment may include the use of major tranquilizers for agitation, and appropriate specific medication for co-existing psychiatric syndromes such as depression or obsessive-compulsive disorder. If antidepressants are indicated, tricyclics with their appetite-stimulating properties are more appropriate than the SSRIs, which can cause weight loss.

• Psychological treatment includes cognitive or supportive therapy individually or in groups, and efforts to correct abnormal body image, perhaps with the aid of measurements or photographs. Psychodynamic approaches are usually unhelpful. Family factors must also be addressed, as in the case of a girl aged 16 who developed anorexia after her achievement of 8 out of 9 ìAî grades at GCSE was perceived by her family as a failure because of the single ìBî. She felt that the only thing she could succeed at was the control of her weight.

Prognosis Recovery is judged by return to normal weight, return of menstruation, and improved psychological and psychosexual adjustment. After five years, about half these patients have recovered fully, and a quarter have improved to some degree. Some cease to be anorexic and go on to develop bulimic features. There is an increased risk of death from suicide, malnutrition or physical complications. Poor prognostic features are a long history, older age of onset, abnormal premorbid personality, poor family relationships and extreme weight loss.

Case Example A 16-year-old schoolgirl, intelligent but lacking in self-confidence, started to diet after a young man said that her tummy was too fat. The girl was working hard for exams at the time, and her parents were having some marital problems.

While eating less and less, she became more and more interested in food and spent much time reading recipe books, and baking cakes for the rest of the family. She slept very little, and would get up early to run for an hour before school. Her weight dropped from 8 to 5 stone within about three months, and eventually her mother insisted on taking her to the doctor because her periods had stopped.

The girl refused to talk about her condition or accept any medical treatment; however she agreed to eat a little more within strictly controlled limits, for example taking an extra half-pint of milk and two slices of bread each day.

Her weight gradually increased again over the next few months but it was six years before menstruation resumed. She achieved a professional qualification, and held a responsible job throughout her 20s despite drinking half a bottle of vodka in private every night. The drinking decreased in her early 30s after she married an older man; they had no children. Now aged 50, she has continued to maintain her weight at 47 kg precisely and becomes very anxious if prevented, by circumstances such as going on holiday, from weighing herself twice a day.

BULIMIA NERVOSA was described by Russell in 1979. It is characterised by:

• Powerful and intractable urges to overeat.
• Efforts to avoid the fattening effects of food by inducing vomiting or abusing purgatives.
• Morbid fear of fatness.

Bulimia and anorexia are closely related. Many anorexic patients exhibit bulimic symptoms, and 25ñ50% of bulimic patients have a past history of anorexia.

Prevalence Depending on diagnostic criteria, about 1ñ2% of young women in the UK may be diagnosed as bulimic. Many cases can be successfully concealed because, unlike those with anorexia nervosa, bulimia sufferers look outwardly healthy.

Epidemiology

• Sex: most cases are female.
• Age: late teens or early 20s.
• Marital status: about 25% are married.

Patients tend to be older, more sexually experienced, and more confident and outgoing than those with anorexia nervosa.

Clinical Features

• Physical: bouts of eating vast quantities of food (bingeing) occur in response to an uncontrollable psychological urge. Self-induced vomiting often follows such episodes. Patients may have abrasions on the back of the hands where they have caught themselves on the teeth trying to induce vomiting.

• Mental: preoccupation with food and weight dominates patientsí lives, but unlike many with anorexia nervosa, bulimic patients show good insight into their abnormal attitudes and behaviour. Depressive symptoms are common. Some patients abuse alcohol and a subgroup shows impulsive behaviour affecting many aspects of life.

Physical Complications Vomiting and laxative abuse may result in alkalosis; this dangerous complication may lead to cardiac arrhythmias (sometimes fatal), fits and renal damage. Another serious but rare complication is acute dilatation or even rupture of the oesophagus or stomach. Swollen parotid glands, and dental damage due to frequent vomiting, may develop. Menstrual irregularity, or amenorrhoea, is common.

Treatment

• Cognitive-behavioural psychotherapy, individual or group.

• Antidepressants, especially the SSRIs in high dose.

Both these approaches are of proven effectiveness.

Prognosis Few long-term studies are yet available, but the symptoms often persist for years and mortality from suicide or physical complications may be up to 20%.

OBESITY is not classed as a psychiatric disorder, but psychologically driven overeating may contribute to its development, and psychological problems may result from it. Increases in prevalence of obesity are of course a lifestyle issue (people are becoming less active) rather than a psychiatric one. So psychiatrists should perhaps concentrate on not making obesity worse, through inappropriate prescribing of psychotropic medication, for too long, or in too high doses. Patients on the newer antipsychotic drugs, especially olanzepine, need careful watching.

FURTHER READING

Palmer B, (2006) Come the revolution- revisiting the management of anorexia nervosa. Advances in Psychiatric Treatment 12: 5-12

Eating Disorders: Nice Guidance