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Anorexia Nervosa
The Facts
Bulimia Nervosa
The Facts

A centre for the treatment of eating disorders

Anorexia Nervosa

Anorexia Nervosa is characterised by a refusal or inability to maintain minimally normal weight, associated with weight loss behaviours, intense fears of gaining weight or becoming fat, distorted body image, undue influence of weight or body shape on self-evaluation, and/or lack of recognition of the seriousness of current low body weight. It is predominantly associated with females but is increasingly being recognised in males (relative prevalence typically estimated at around 10:1). The exact incidence remains disputed but is in the region of 1 – 2% of the population.

Anorexia is classified into 2 types:

  • restricting type – weight controlled by restriction of food intake and exercise
  • binge eating type – associated with episodes of self induced vomiting, binge eating or purging

The majority of sufferers (up to 50%) fall into a more general category of EDNOS – “eating disorder not otherwise specified” i.e. with symptoms of both anorexia and bulimia.

Anorexia Nervosa typically begins with excessive concern about body weight leading to dieting and a preoccupation with losing weight. The diet becomes gradually more restrictive whilst at the same time there is an increasing preoccupation with food. Commonly associated behaviours initially include maintaining an interest in cooking for the family and others but eating little themselves and claiming to have eaten substantial amounts. They may begin to hoard food or eat slowly with others. Some sufferers may purge and vomit, feeling intensely guilty after eating, usually having binged due to extreme feelings of hunger. Controlling the basic urge to eat is associated with a sense of mastery over other overwhelming feelings and a perception of having control over other areas of one’s life. Invariably this provokes a response from family and friends which may inadvertently reinforce abnormal eating behaviour.

The aetiology or causes remain far from clear, in part because the diagnostic criteria are descriptions of symptoms which can merely reflect ever more desperate attempts to control unmanageable feelings. These unmanageable feelings may have been generated through a variety of mechanisms. For some, Anorexia Nervosa is a more traditional obsessional condition although the biological effects of starvation are thought to generate obsessional states of mind through separate mechanisms. For others, Anorexia may be a means of controlling overwhelming and unmanageable feelings, related to uncomfortable family dynamics, or as a strategy for numbing oneself or absenting oneself from wider social pressures.

Increasingly it is thought that genetics plays an important role however this may be via independent variables such as perfectionism or rigidity of character. Certainly, there is a significantly increased risk if there is a family history of eating disorders with putative biological links. Other more obvious predisposing factors are poorly understood; the role of the media, the changing role and expectations of women (and men) in society, and a societal preoccupation with “thinness”. Earlier psychoanalytic models have poor scientific backing but in practice one continues to see young girls terrified of developing into women.

Other associated factors include being part of Western society, certain occupations (modelling, ballet dancers, high achieving schools) and a history of obesity. Research suggests an equal distribution across all social classes but, for complicated reasons, specialist services show an overwhelming predominance of upper / middle class patients. Certainly, high achieving individuals who remorselessly drive themselves ever harder are overly represented.

Clinical Features:

The sooner the signs and symptoms can be recognized, the better. Once abnormal eating (and emotional regulation) patterns become established it becomes ever harder to recover. The main clinical features include a range of biological changes, behavioural changes, psychological signs, cognitive changes and abnormal eating behaviours.

Biological features include: amenorrhea, fatigue, cold intolerance, constipation, emaciation and muscle loss (see below).

Behavioural changes include a variety of strategies expressly aimed at decreasing weight. These generally occur in secret and can be perceived as shameful. They often incorporate excessive exercise, restricting food intake, laxative abuse, diuretic abuse, complex distraction strategies, and may involve slimming pills and vomiting.

Psychological and social changes include: distorted body image, a dread or morbid fear of weight gain, depression, anxiety, obsessive phenomena, social withdrawal and isolation, irritability, low self esteem, passivity and withdrawal, and deliberate self harm or suicidal behaviour.

Cognitive changes might include: rigidity of cognitive processing, poor concentration, poor memory and “black and white” thinking.

Finally, abnormal eating behaviours include: a detailed interest in the calorific content of foods, slow or picky eating, playing with food without eating it, only eating alone, hiding or disposing of food, and excessive interest in preparing food for others at the same time as losing weight.

Physical symptoms involve all major systems of the body including:

  • emaciation; cachexia and malnutrition
  • dehydration
  • sleep disturbances
  • fatigue and bruising – anaemia, leucopenia (low white cells leading to recurrent infections), thrombocytopenia (low platelets leading to poor clotting)
  • muscle wasting with significant proximal (i.e. close to the body’s trunk) muscle weakness resulting in difficulty standing from the squat position (the “squat” test)
  • cold extremities, hypothermia and poor peripheral circulation
  • Gastrointestinal disturbances resulting in low gastric secretions, delayed gastric emptying, altered gut motility, gastric atrophy, and possibly acute pancreatitis
  • Cardiovascular abnormalities such as bradycardia (slow heart beat), arrhythmias (abnormal heart beats), cardiomyopathy, prolonged QT interval on ECGs, oedema (fluid retention particularly around the ankles and lower limbs) and hypotension
  • endocrine and metabolic disturbances such as decreased metabolic rate, hypocalcaemia, osteoporosis and risk of fractures and amenorrhea
  • neurological difficulties including peripheral neuropathy
  • difficulties with urinating including frequency of micturition, urgency, and nocturia
  • renal stones
  • fine “lanugo” hair on the face and trunk, coarse dry skin, and hair loss
  • reduced growth before puberty
  • infertility and low birth weight babies
  • seizures
  • additional physiological complications arising from the use of purgatives including hypokalaemia (low blood potassium) and cardiac arrest.

Diagnostic Criteria:

  • low body weight; 15% or more below expected or BMI less than 17.5 (see above)
  • self induced weight loss including avoidance of fattening food, restriction of food intake, vomiting, purging, excessive exercise and use of appetite suppressants or diuretics
  • body image distortion with a morbid dread of fatness, overvalued idea about body shape and imposed low weight threshold
  • endocrine disorders such as HPA axis dysfunction eg: amenorrhea, decreased sexual interest or impotence, increased GH levels, increased cortisol, altered TFT and abnormal insulin secretion
  • delayed or arrested puberty if the onset is pre-pubertal.

In atypical cases one or more of these key features may be absent or all are present but to a lesser degree.


The treatments, causes and outcomes from Anorexia remain poorly researched and consequently poorly understood. Early diagnosis and rapid access to specialist advice and, if necessary, treatment are considered essential. A significant proportion of sufferers can, with support, information and guidance, manage their illnesses adequately. However more complex or entrenched sufferers often require substantial inpatient or highly intensive out-patient care aimed at recovery from both classical eating issues and wider social difficulties which will have often become ingrained.

The prognosis remains variable and difficult to predict. Anorexia Nervosa is considered to be one of the most dangerous of mental illnesses with a mortality rate of up to 20%.  As far as is currently understood, a poorer prognosis is indicated (but not restricted or limited to): older age at onset, a previous history of mental health or personality difficulties, a long duration of illness, a lack of social support or disturbed family relationships, severe low weight, inability to engage in treatment or slow motivation to change and detention under the Mental Health Act (possibly secondary to the severity of illness).


The majority of people suffering from mild to moderate Anorexia can be successfully treated in the community by linking together numerous services including the GP, psychiatrist, nurses, dietitians and specialist or generic counsellors. However, those seriously underweight, presenting with severe complications due to their low weight, should be considered for treatment as inpatients. Criteria for inpatient care include:

  • rapid or excessive weight loss
  • severe electrolyte imbalance
  • serious physiological complications such as hypothermia< 36°C, fainting due to bradycardia, or marked postural hypotension
  • cardiac complications or acute medical disorders
  • marked change of mental state due to severe malnutrition
  • psychosis or risk of suicide
  • failure of out-patient treatment

NICE guidance makes specific recommendations about the treatment of Anorexia Nervosa although it is acknowledged in any available guidance that there remains little robust evidence to guide clinical decisions (see NICE guidance As such, decisions should be made in conjunction with specialists in the treatment of Anorexia Nervosa and fit the needs of the individual. Reliance on measures such as BMI < 13 = admission are crude and potentially dangerous as chronicity of illness, rate of weight loss and other factors should direct clinical decisions alongside physical examinations. A range of comprehensive guides to assessing and managing the medical risks associated with eating disorders exist – for example comprehensive guidance can be found here.

Admission should not be in any way punitive and the once prevalent behavioural inpatient regimes are no longer considered credible. Importantly, the goals of in-patient care should be made clear before admitting anyone, including addressing their physical and psychiatric complications, the development of a healthy eating pattern, and the role of psychological therapy to help resolve underlying conflicts.

Ideally, the aim of admission is to increase and maintain a “normal” weight but also to normalize eating patterns, develop a normal perception of hunger and satiety and correct the biological and psychological complications of the starvation. However an acceptance of the need to achieve these goals is, by the very nature of the illness, terrifying and overwhelming at point of admission. For a number of reasons, admission is considered to be safest and most efficacious if done in specialist units where the fears and ambivalence of sufferers can be contained and understood. Most units aim for a slow and steady increase in weight alongside specialist therapy and support of one form or another. Such units need to also monitor and address the range of physical complications arising from severe starvation.

Such units need to also help an individual rebuild (or build for the first time) a sense of self without Anorexia; to be able to form, maintain and manage relationships, set goals and pursue aspirations for the future and begin to identify a direction in life – all of which have usually been severely disturbed by the consequences of Anorexia.

Treatment rarely involves medication although co-morbid psychiatric or physical illness can occur at any stage of recovery. Most importantly, the initial phase of re-feeding can, for complex reasons, be extremely dangerous from low weights requiring specialist dietetic advice and monitoring together with regular blood monitoring.

In rare, extreme circumstances the Mental Health Act can be used and feeding be given as a treatment. However such treatment needs to be as a last resort and lifesaving measure after careful specialist consideration and treatment delivered in specialist centres. Collaboration, persistence and risk management are the mainstays of treatment, interwoven with optimism and hope. In the high majority of cases, and with enough time and support, Anorexia can be beaten.