Anorexia Nervosa is a psychiatric diagnosis that describes an eating disorder characterized by low body weight and body image distortion with an obsessive fear of gaining weight. Individuals with anorexia are known to commonly control body weight through the means of voluntary starvation, purging, vomiting, excessive exercise, or other weight control measures, such as diet pills or diuretic drugs. It primarily affects adolescent females, however approximately 10% of people with the diagnosis are male. Anorexia nervosa is a complex condition, that eventually, in most cases leads to death, involving neurobiological, psychological, and sociological components.
The term anorexia is of Greek origin: a (α, prefix of negation), n (ν, link between two vowels) and orexis (ορεξις, appetite) thus meaning a lack of desire to eat. A person who is diagnosed with anorexia nervosa is most commonly referred to with the adjectival form anorexic. The noun form, "anorectic" is generally not used in this context and usually refers to drugs that suppress appetite.
"Anorexia nervosa" is frequently shortened to "anorexia" in both the popular media and television reports. This is technically incorrect, as the term "anorexia" used separately refers to the medical symptom of reduced appetite (which therefore is distinguishable from anorexia nervosa in being non-psychiatric).
Although biological tests can aid the diagnosis of anorexia, the diagnosis is based on a combination of behavior, reported beliefs and experiences, and physical characteristics of the patient. Anorexia is typically diagnosed by a clinical psychologist, psychiatrist or other suitably qualified clinician. Notably, diagnostic criteria are intended to assist clinicians, and are not intended to be representative of what an individual sufferer feels or experiences in living with the illness.
To be diagnosed as having anorexia nervosa, according to the DSM-IV-TR, a person must display:
Furthermore, the DSM-IV-TR specifies two subtypes:
The ICD-10 criteria are similar, but in addition, specifically mention
Changes in brain structure and function are early signs of the condition. Enlargement of the ventricles of the brain is thought to be associated with starvation, and is partially reversed when normal weight is regained. Anorexia is also linked to reduced blood flow in the temporal lobes, although since this finding does not correlate with current weight, it is possible that it is a risk trait rather than an effect of starvation.
Other effects may include the following:
Fragile appearance; frail body image
Additionally, it is important to note that an individual may still suffer from a health- or life-threatening eating disorder (e.g., sub-clinical anorexia nervosa or EDNOS) 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.
Feminist writers such as Susie Orbach and Naomi Wolf have criticized the medicalisation of extreme dieting and weight-loss as locating the problem within the affected women, rather than in a society that imposes concepts of unreasonable and unhealthy thinness as a measure of female beauty and gaining weight.
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. 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.
Recent studies also suggest anorexia may be linked to an autoimmune response to melanocortin peptides which influence appetite and stress responses. Additional factors appear to be involved in the development of anorexia nervosa in elderly patients. All neurotransmitters associated with appetite decline with age. In addition there is a decline in levels of Substance P and Neuropeptide Y. Substance P is the transmitter that carries complex taste information from the taste-buds to the brain. Neuropeptide Y regulates carbohydrate cravings.
Anorexic eating behavior 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. A recent review of research in this area suggests that this is not a perceptual problem, but one of how the perceptual information is evaluated by the affected person. Recent research suggests people with anorexia nervosa may lack a type of overconfidence bias in which the majority of people feel themselves more attractive than others would rate them. In contrast, people with anorexia nervosa seem to more accurately judge their own attractiveness compared to unaffected people, meaning that they potentially lack this self-esteem boosting bias.
People with anorexia have been found to have certain personality traits that are thought to predispose them to develop eating disorders. High levels of obsession (being subject to intrusive thoughts about food and weight-related issues), restraint (being able to fight temptation), and clinical levels of perfectionism (the pathological pursuit of personal high-standards and the need for control) have been cited as commonly reported factors in research studies.
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 one or more personality disorders 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. Nevertheless, one reasonably reliable finding is that those with anorexia have poor cognitive flexibility (the ability to change past patterns of thinking, particularly linked to the function of the frontal lobes and executive system).
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.
Although there has been quite a lot of research into psychological factors, there are relatively few hypotheses which attempt to explain the condition as a whole.
Professor Chris Fairburn, of the University of Oxford and his 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 developed with psychological therapies, particularly cognitive behavioral therapy, in mind, and so suggests areas where clinicians could provide psychological treatment.
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 behavior. This includes clinical perfectionism, chronic low self-esteem, mood intolerance (inability to cope appropriately with certain emotional states) and interpersonal difficulties.
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 countries. However, it is notable that other cultures may not display the same 'fat phobic' worries about becoming fat as those with the condition in the West, and instead may present with low appetite with the other common features.
There is a high rate of reported child sexual abuse experiences in clinical groups of 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, those who have experienced such abuse are more likely to have more serious and chronic symptoms.
The Internet has enabled anorexics and bulimics to contact and communicate with each other outside of a treatment environment, with much lower risks of rejection by mainstream society. A variety of websites exist, some run by sufferers, some by former sufferers, and some by professionals. 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. Such websites were the subject of significant media interest, largely focusing on concerns that these communities could encourage young women to develop or maintain eating disorders, and many were taken offline as a result.
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. However, this review also noted that there are only a small number of randomised controlled trials on which to base this recommendation, and no specific type of psychotherapy seems to show any overall advantage when compared to other types. 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 been 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. It is common, however, for antidepressants to be prescribed, often with the intent of trying to treat the associated anxiety and depression.
Supplementation with 14mg/day of zinc is recommended as routine treatment for anorexia nervosa due to a study showing a doubling of weight regain after treatment with zinc was begun. The mechanism of action is hypothesized to be an increased effectiveness of neurotransmission in various parts of the brain, including the amygdala, after adequate zinc intake begins resulting in increased appetite.
There are various non-profit and community groups that offer support and advice to people who suffer from anorexia or who care for someone who does.