A psychological illness which mainly affects young women, characterized by significant weight loss (usually deliberately induced), an unrealistic fear of being overweight, and a loss of normal menstrual functioning. There is a distortion of body image, and sufferers are frequently hyperactive, have faddish eating habits, and some have depressed mood. The term was first used by the English physician Sir William Gull in 1874, but there are clear historical accounts of a similar condition dating back centuries, indicating that this is not a symptom of modern living. Current views hold that there are both biological and psychological causes, and that early treatment is likely to produce a better outcome than any delay, which may lead to chronicity of the illness and a fatal outcome in a proportion of sufferers.
Anorexia nervosaClassifications and external resources
| ICD-10 | F50.0-F50.1 |
|---|---|
| ICD-9 | 307.1 |
Anorexia nervosa is a psychiatric diagnosis that describes an eating disorder characterized by low body weight and body image distortion. Individuals with anorexia often control body weight by voluntary starvation, purging, vomiting, excessive exercise, or other weight control measures, such as diet pills or diuretic drugs.
Anorexia is a life threatening condition that can put a serious strain on many of the body's organs and physiological resources. Those who develop anorexia before adulthood may suffer stunted growth and subsequent low levels of essential hormones (including sex hormones) and chronically increased cortisol levels. Anorexia is also linked to reduced blood flow in the temporal lobes, although as this finding does not correlate with current weight, it is possible that it is a risk trait, rather than an effect of starvation.
Terminology
A person who is suffering from anorexia is referred to as 'anorexic' or (less commonly) as 'an anorectic'.
"Anorexia nervosa" is frequently shortened to "anorexia" in both the popular media and scientific literature.
Diagnosis and clinical features
The most commonly used criteria for diagnosing anorexia are from the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) and the World Health Organization's International Statistical Classification of Diseases and Related Health Problems (ICD).
Although biological tests can aid the diagnosis of anorexia, the diagnosis is based on a combination of behaviour, reported beliefs and experiences, and physical characteristics of the patient.
The full ICD-10 diagnostic criteria for anorexia nervosa can be found here, and the DSM-IV-TR criteria can be found here.
To be diagnosed as having anorexia nervosa, according to the DSM-IV-TR, a person must display:
Refusal to maintain body weight at or above a minimally normal weight for age and height (e.g., weight loss leading to maintenance of body weight less than 85% of that expected;Furthermore, the DSM-IV-TR specifies two subtypes:
Restricting Type: during the current episode of anorexia nervosa, the person has not regularly engaged in binge-eating or purging behavior (that is, self-induced vomiting, over-exercise or the misuse of laxatives, diuretics, or enemas) Binge-Eating Type or Purging Type: during the current episode of anorexia nervosa, the person has regularly engaged in binge-eating OR purging behavior (that is, self-induced vomiting, over-exercise or the misuse of laxatives, diuretics, or enemas).Presentation
There are a number of features, that although not necessarily diagnostic of anorexia, have been found to be commonly (but not exclusively) present in those with this eating disorder.
Psychological
Distorted body image Poor insight Self-evaluation largely, or even exclusively, in terms of their shape and weight Pre-occupation or obsessive thoughts about food and weight Perfectionism OCD (obsessive compulsive disorder)Emotional
Low self-esteem and self-efficacy Clinical depression or chronically low mood Intense fear about becoming overweight MoodinessInterpersonal and social
Poor or deteriorating school performance Withdrawal from previous friendships and other peer-relationships Deterioration in relationships with the familyPhysiological
Endocrine disorder, leading to cessation of periods in girls (amenorrhoea) Starvation symptoms, such as reduced metabolism, slow heart rate (bradycardia), hypotension, hypothermia and anemia. Growth of lanugo hair over the body Abnormalities of mineral and electrolyte levels in the body Zinc deficiency Often a reduction in white blood cell count Reduced immune system function Body mass index less than 17.5 in adults, or 85% of expected weight in children Possibly with pallid complexion and sunken eyes Creaking joints and bones Collection of fluid in ankles during the day and around eyes during the night Constipation Very dry/chapped lips due to malnutrition Poor circulation, resulting in common attacks of 'pins and needles' and purple extremities In cases of extreme weight loss, there can be nerve deterioration, leading to difficulty in moving the feet headaches, due to malnutritionBehavioural
Excessive exercise, food restriction Fainting Secretive about eating or exercise behaviour Possible self-harm, substance abuse or suicide attemptsDiagnostic issues and controversies
The distinction between the diagnoses of anorexia nervosa, bulimia nervosa and eating disorder not otherwise specified (EDNOS) is often difficult to make in practice and there is considerable overlap between patients diagnosed with these conditions. Furthermore, seemingly minor changes in a patient's overall behaviour or attitude (such as reported feeling of 'control' over any bingeing behaviour) can change a diagnosis from 'anorexia: binge-eating type' to bulimia nervosa.
Additionally, it is important to note that an individual may still suffer from a health- or life-threatening eating disorder (e.g., subclinical anorexia nervosa or EDNOS: eating disorder, not otherwise specified) even if one diagnostic sign or symptom is still present. For example, a substantial number of patients diagnosed with EDNOS meet all criteria for diagnosis of anorexia nervosa, but lack the three consecutive missed menstrual cycles needed for a diagnosis of anorexia.
Causes and contributory factors
It is clear that there is no single cause for anorexia and that it stems from a mixture of social, psychological and biological factors.
Physiological factors
Genetic factors
Family and twin studies have suggested that genetic factors contribute to about 50% of the variance for the development of an eating disorder and that anorexia shares a genetic risk with clinical depression.
Several rodent models of anorexia have been developed which largely involve subjecting the animals to various environmental stressors or using gene knockout mice to test hypotheses about the effects of certain genes on related behaviour. These models have suggested that the hypothalamic-pituitary-adrenal axis may be a contributory factor, although the models have been criticised as food is being limited by the experimenter and not the animal, and these models cannot take into account the complex cultural factors known to affect the development of anorexia nervosa. A recent review of the scientific literature has suggested that anorexia is linked to a disturbed serotonin system, particularly to high levels at areas in the brain with the 5HT1A receptor - a system particularly linked to anxiety, mood and impulse control. There is evidence, however, that both personality characteristics (such as anxiety and perfectionism) and disturbances to the serotonin system are still apparent after patients have recovered from anorexia, suggesting that these disturbances are likely to be causal risk factors.
Recent studies also suggest anorexia may be linked to an autoimmune response to melanocortin peptides which influence appetite and stress responses.
Psychological factors
There has been a significant amount of work into psychological factors that suggests how biases in thinking and perception help maintain or contribute to the risk of developing anorexia.
Anorexic eating behaviour is thought to originate from feelings of fatness and unattractiveness and is maintained by various cognitive biases that alter how the affected individual evaluates and thinks about their body, food and eating.
One of the most well-known findings is that people with anorexia tend to over-estimate the size or fatness of their own bodies. Recent research suggests people with anorexia may lack a type of overconfidence bias in which the majority of people feel themselves more attractive than others would rate them.
People with anorexia have been found to have certain personality traits that are thought to predispose them to develop eating disorders.
It is often the case that other psychological difficulties and mental illnesses exist alongside anorexia nervosa in the sufferer. Clinical depression, obsessive compulsive disorder, substance abuse and personality disorder are the most likely conditions to be comorbid with anorexia, and high-levels of anxiety and depression are likely to be present regardless of whether they fulfill diagnostic criteria for a specific syndrome.
Research into the neuropsychology of anorexia has indicated that many of the findings are inconsistent across studies and that it is hard to differentiate the effects of starvation on the brain from any long-standing characteristics.
Other studies have suggested that there are some attention and memory biases that may maintain anorexia. Attentional biases seem to focus particularly on body and body-shape related concepts, making them more salient for those affected by the condition, and some limited studies have found that those with anorexia may be more likely to recall related material than unrelated material.
Fairburn and colleagues have created a 'transdiagnostic' model, in which they aim to explain how anorexia, as well as related disorders such as bulimia nervosa and ED-NOS, are maintained.
Their model is based on the idea that all major eating disorders (with the exception of obesity) share some core types of psychopathology which help maintain the eating disorder behaviour. A recent epidemiological study of 989,871 Swedish residents indicated that gender, ethnicity and socio-economic status were large influences on the chance of developing anorexia, with those with non-European parents among the least likely to be diagnosed with the condition, and those in wealthy, white families being most at risk. A classic study by Garner and Garfinkel demonstrated that those in professions where there is a particular social pressure to be thin (such as models and dancers) were much more likely to develop anorexia during the course of their career, and further research has suggested that those with anorexia have much higher contact with cultural sources that promote weight-loss.
Although anorexia nervosa is usually associated with Western cultures, exposure to Western media is thought to have led to an increase in cases in non-Western counties.
There is a high-rate of child sexual abuse experiences in those who have been diagnosed with anorexia (up to 50% in those admitted to inpatient wards, with a lesser prevalence among people treated in the community). Although prior sexual abuse is not thought to be a specific risk factor for anorexia (although it is a risk factor of mental illness in general), those who have experienced such abuse are more likely to have more serious and chronic symptoms. The majority of such sites support a medical view of anorexia as a disorder to be cured, although some people affected by anorexia have formed online pro-ana communities that reject the medical view and argue that anorexia is a 'lifestyle choice', using the internet for mutual support, and to swap weight-loss tips.
Prognosis
Anorexia is thought to have the highest mortality rate of any psychiatric disorder, with approximately 10% of those who are diagnosed with the disorder eventually dying due to related causes.
Incidence, prevalence and demographics
The majority of research into the incidence and prevalence of anorexia has been done in Western industrialised countries, so results are generally not applicable outside these areas. However, recent reviews of studies on the epidemiology of anorexia have suggested an incidence of between 8 and 13 cases per 100,000 persons per year and an average prevalence of 0.3% using strict criteria for diagnosis.
Treatment
The first line treatment for anorexia is usually focused on immediate weight gain, especially with those who have particularly serious conditions that require hospitalization. In the majority of cases, however, people with anorexia are treated as outpatients, with input from physicians, psychiatrists, clinical psychologists and other mental health professionals.
A recent clinical review has suggested that psychotherapy is an effective form of treatment and can lead to restoration of weight, return of menses among female patients, and improved psychological and social functioning when compared to simple support or education programmes. Family therapy has also been found to be an effective treatment for adolescents with anorexia and in particular, a method developed at the Maudsley Hospital is widely used and found to maintain improvement over time.
Drug treatments, such as SSRI or other antidepressant medication, have not found to be generally effective for either treating anorexia, or preventing relapse although it has also been noted that there is a lack of adequate research in this area.
There are various non-profit and community groups that offer support and advice to people who have anorexia, or are the carer of someone who does. Something Fishy Eating Disorders website Web4health Anorexia nervosa section pdf of American Psychiatric Association eating disorders leaflet Mental Health Matters: Anorexia Psych Forums: Anorexia Forum Anorexia Nervosa Information on Anorexia Nervosa
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