| Anorexia Nervosa | |
|---|---|
| Classification and external resources | |
| ICD-10 | F50.0-F50.1 |
| ICD-9 | 307.1 |
| OMIM | 606788 |
| DiseasesDB | 749 |
| eMedicine | emerg/34 med/144 |
Anorexia nervosa is an eating disorder characterized by extremely low body weight, distorted body image and an obsessive fear of gaining weight. [1]
The term anorexia nervosa was established in 1873 by Sir William Gull, one of Queen Victoria's personal physicians.[2] The term 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.[3]
Contents |
A definition of anorexia nervosa was established by the 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).
The DSM-IV-TR criteria include intense fear of gaining weight, a refusal to maintain body weight above 85% of the expected weight for a given age and height, and (in women) three consecutive missed periods. One other required criterion is either refusal to admit the seriousness of the weight loss, or undue influence of shape or weight on one's self image, or a disturbed experience in one's shape or weight. There are two types: the binge-eating/purging types eat too much or purge themselves, and the restricting types do not.[4]
The ICD-10 criteria are similar, but in addition, specifically mention
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 behavior or attitude can change a diagnosis from "anorexia: binge-eating type" to bulimia nervosa. It is not unusual for a person with an eating disorder to "move through" various diagnoses as his or her behavior and beliefs change over time.[5]
Twin studies have estimated a high heritability of anorexia nervosa, ranging from 56% to as high as 84%. [6][7][8] Subsequent association studies have shown polymorphisms in genes involved in regulation of eating behavior, motivation and reward mechanics, personality and emotion to be associated with the development of Anorexia Nervosa. Due to the low prevalence of anorexia nervosa, association studies published commonly have problems with low power due to small sample sizes. However, confirmed and consistent results have been published showing associations to polymorphisms associated with the genes encoding agouti related peptide, brain derived neurotrophic factor, catechol-o-methyl transferase, SK3 and opioid receptor delta-1.[9] In one study, variations in the norepinephrine transporter gene promoter were associated with restrictive anorexia nervosa, but not binge-purge anorexia (though the latter may have been due to small sample size).[10]
Anorexia may be linked to a disturbed serotonin system,[11] particularly to high levels at areas in the brain with the 5HT1A receptor - a system particularly linked to anxiety, mood and impulse control. Starvation has been hypothesized to be a response to these effects, as it is known to lower tryptophan and steroid hormone metabolism, which might reduce serotonin levels at these critical sites and ward off anxiety. Other studies of the 5HT2A serotonin receptor (linked to regulation of feeding, mood, and anxiety), suggest that serotonin activity is decreased at these sites. There is evidence that both personality characteristics and disturbances to the serotonin system are still apparent after patients have recovered from anorexia.[12]
Changes in brain structure and function are early signs often to be associated with starvation, and is partially reversed when normal weight is regained.[13] Anorexia is also linked to reduced blood flow in the temporal lobes. It is possible that it is a risk trait rather than an effect of starvation.[14]
Anorexia may be linked to an autoimmune response to melanocortin peptides which influence appetite and stress responses.[15]
Zinc deficiency may play a role in Anorexia. It is not thought responsible for causation of the initial illness but there is evidence that it may be an accelerating factor that deepens the pathology of the anorexia. A 1994 randomized, double-blind, placebo-controlled trial showed that zinc (14 mg per day) doubled the rate of body mass increase compared to patients receiving the placebo.[16]
Anorexic eating behavior is thought to originate from an obsessive fear of gaining weight due to a distorted self image[17] and is maintained by various cognitive biases that alter how the affected individual evaluates and thinks about their body, food and eating. This is not a perceptual problem, but one of how the perceptual information is evaluated by the affected person.[18] People with anorexia nervosa seem to more accurately judge their own body image while lacking a self-esteem boosting bias.[19]
People with anorexia nervosa also have other psychological difficulties and mental illness. Clinical depression, obsessive compulsive disorder, substance abuse and one or more personality disorders may be the most likely conditions to be comorbid with anorexia. High-levels of anxiety and depression are likely to be present regardless of whether they fulfill diagnostic criteria for a specific syndrome.[20]
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. One finding is that those with anorexia have poor cognitive flexibility.[21]
Other studies have suggested that there are some attention and memory biases that may maintain anorexia.[22]
Sociocultural studies have highlighted the role of cultural factors, such as the promotion of thinness as the ideal female form in Western industrialized nations, particularly through the media.[23][24] 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.[25] People 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,[26] and further research has suggested that those with anorexia have much higher contact with cultural sources that promote weight-loss.[27]
There is a high rate of reported child sexual abuse experiences in clinical groups of who have been diagnosed with anorexia. 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.[28]
Following an initial suggestion of relationship between anorexia nervosa and autism,[29][30][31] a longitudinal study of 102 participants into teenage onset anorexia nervosa conducted in Sweden found that 23% of people with a long-standing eating disorder are on the autism spectrum.[32][33][34][35][36][37][38] Those on autism spectrum tend to have a worse outcome,[39] but may benefit from the combined use of behavioural and pharmacological therapies tailored to ameliorate autism rather than anorexia nervosa per se.[40][41] Other studies may suggest that autistic traits are common in people with anorexia nervosa.[42][43][44][45][46] However, in one report it was concluded that these findings need to be replicated using larger samples with more sensitive measures.[47]
It is also proposed that conditions on the autism spectrum make up the cognitive endophenotype underlying anorexia nervosa and appealed for increased interdisciplinary collaboration (see figure to right).[5]
Anorexia is thought to have the highest mortality rate of any psychiatric disorder, with anywhere from 6-20% of those who are diagnosed with the disorder eventually dying from related causes.[48] The suicide rate of people with anorexia is also higher than that of the general population.[49] In a longitudinal study women diagnosed with either DSM-IV anorexia nervosa (n = 136) or bulimia nervosa (n = 110) respectively who were assessed every 6 – 12 months over an 8 year period are at a considerable risk of committing suicide. Clinicians were warned of the risks as 15% of subjects reported at least one suicide attempt. It was noted that significantly more anorexia (22.1%) than bulimia (10.9%) subjects made a suicide attempt.[50]
Treatment for anorexia nervosa tries to address three main areas. 1) Restoring the person to a healthy weight; 2) Treating the psychological disorders related to the illness; 3) Reducing or eliminating behaviours or thoughts that originally led to the disordered eating.[51]
Drug treatments, such as SSRI or other antidepressant medication, have not been found to be generally effective for either treating anorexia,[52] or preventing relapse[53] although it has also been noted that there is a lack of adequate research in this area.
A pilot study into the effectiveness on Cognitive Behaviour Therapy reduced perfectionism and rigidity in 17 out of 19 participants[54] although further evaluation is needed.
Family based treatment has also been found to be an effective treatment for adolescents with short term anorexia.[55] At 4 to 5 year follow up one study shows full recovery rate of 60 - 90% with 10-15% remaining seriously ill. This compares favourable to other treatments such as inpatient care where full recovery rates vary between 33-55%.[56]
Anorexia has 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.[57][58] The condition largely affects young adolescent women, with between 15 and 19 years old making up 40% of all cases. Approximately 90% of people with anorexia are female.[59]
| Anorexia Nervosa | |
|---|---|
| Classification and external resources | |
| ICD-10 | F50.0-F50.1 |
| ICD-9 | 307.1 |
| OMIM | 606788 |
| DiseasesDB | 749 |
| eMedicine | emerg/34 med/144 |
| MeSH | D000856 |
Anorexia nervosa is an eating disorder characterized by refusal to maintain a healthy body weight, and an obsessive fear of gaining weight due to a distorted self image[1][2] which may be maintained by various cognitive biases[3] that alter how the affected individual evaluates and thinks about their body, food and eating. It is a serious mental illness with a high incidence of comorbidity and also the highest mortality rate of any psychiatric disorder.[4]
It can affect men and women of all ages, races, socioeconomic and cultural backgrounds.[5][6][7][8][9]
The term anorexia nervosa was established in 1873 by Sir William Gull, one of Queen Victoria's personal physicians.[10] The term 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.[11]
Contents |
A patient suffering from anorexia nervosa will exhibit a number of signs and symptoms, some of which are listed below. The type and severity of the signs and symptoms vary in each case and may be present but not readily apparent. Anorexia nervosa and the associated malnutrition that results from self-imposed starvation, can cause severe complications in every major organ system in the body.[12][13][14]
Possible signs of anorexia nervosa
| ||||
File:Russell's Russell's sign scarring on knuckles due to sticking fingers down throat to force vomiting[15] [[File:|thumb|right|160px|Chilblains, also known as Perniosis.
| ||||
Dermatologic signs of anorexia nervosa[26]
| ||||
| xerosis | telogen effluvium | carotenoderma | acne | hyperpigmentation |
| seborrheic dermatitis | acrocyanosis | perniosis | petechiae | livedo reticularis |
| interdigital intertrigo | paronychia | generalized pruritus | acquired striae distensae | angular stomatitis |
| prurigo pigmentosa | edema | linear erythema craquele | acrodermatitis enteropathica | pellagra |
Possible medical complications of anorexia nervosa
| ||||
| constipation[27] | diarrhea[28] | electrolyte imbalance[29] | cavities[30] | tooth loss[31] |
| cardiac arrest[32] | amenorrhoea[33] | edema[34] | osteoporosis[35] | osteopenia[36] |
| hyponatremia[37] | hypokalemia[38] | optic neuropathy[39] | brain atrophy[40][41] | leukopenia[42][43] |
Studies have hypothesized that the continuance of disordered eating patterns may be epiphenomena of starvation. The results of the Minnesota Starvation Experiment showed that normal controls exhibit many of the behavioral patterns of anorexia nervosa when subjected to starvation. This may be due to the numerous changes in the neuroendocrine system, which results in a self perpetuating cycle.[44][45][46][47] Studies have suggested that the initial weight loss such as dieting may be the triggering factor in developing AN in some cases, possibly due to an already inherent predisposition toward AN. One study reports cases of AN resulting from unintended weight loss that resulted from varied causes such as a parasitic infection, medication side effects, and surgery. The weight loss itself was the triggering factor.[48][49]
Sociocultural studies have highlighted the role of cultural factors, such as the promotion of thinness as the ideal female form in Western industrialized nations, particularly through the media.[74][75] 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.[76] People 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,[77] and further research has suggested that those with anorexia have much higher contact with cultural sources that promote weight-loss.[78]
There is a high rate of reported child sexual abuse experiences in clinical groups of who have been diagnosed with anorexia. 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.[79]
Since Gillberg's (1985) and others initial suggestion of relationship between anorexia nervosa and autism,[80][81][82] a large scale longitudinal study into teenage onset anorexia nervosa conducted in Sweden confirmed that 23% of people with a long-standing eating disorder are on the autism spectrum.[83][84][85][86][87][88][89] Those on autism spectrum tend to have a worse outcome,[90] but may benefit from the combined use of behavioural and pharmacological therapies tailored to ameliorate autism rather than anorexia nervosa per se.[91][92] Other studies, most notably research conducted at the Maudsley Hospital UK, furthermore suggest that autistic traits are common in people with anorexia nervosa, shared traits include e.g. executive function, autism quotient score, central coherence, theory of mind, cognitive-behavioural flexibility, emotion regulation and understanding facial expressions.[93][94][95][96][97][98]
Zucker et al. (2007) proposed that conditions on the autism spectrum make up the cognitive endophenotype underlying anorexia nervosa and appealed for increased interdisciplinary collaboration (see figure to right).[99] A pilot study into the effectiveness Cognitive Behaviour Therapy, which based its treatment protocol on the hypothesised relationship between anorexia nervosa and an underlying autistic like condition, reduced perfectionism and rigidity in 17 out of 19 participants.[100]
The initial diagnosis should be made by a competent medical professional. There are multiple medical conditions, such as viral or bacterial infections, hormonal imbalances, neurodegenerative diseases and brain tumors which may mimic psychiatric disorders including anorexia nervosa. According to an in depth study conducted by psychiatrist Richard Hall as published in the Archives of General Psychiatry:
| Medical Tests used in the Diagnosis and Assessment of Anorexia Nervosa | |
|---|---|
| |
Anorexia nervosa is classified as an Axis I[131] disorder in the Diagnostic and Statistical Manual of Mental Health Disorders (DSM-IV). Published by The American Psychiatric Association. The DSM-IV should not be used by laypersons to diagnose themselves.
[[File:|thumb|right|260px|Painting signed 2004]]
There are various other psychological issues that may factor into anorexia nervosa, some fulfill the criteria for a separate Axis I diagnosis or a personality disorder which is coded Axis II and thus are considered comorbid to the diagnosed eating disorder. Axis II disorders are subtyped into 3 "clusters", A, B and C.The causality between personality disorders and eating disorders has yet to be fully established.[138] Some people have a previous disorder which may increase their vulnerability to developing an eating disorder.[139][140][141] Some develop them afterwards.[142] The severity and type of eating disorder symptoms have been shown to affect comorbidity.[143]
BDD is a chronic and debilitating condition which may lead to social isolation, major depression, suicidal ideation and attempts. Neuroimaging studies to measure response to facial recognition have shown activity predominately in the left hemisphere in the left lateral prefrontal cortex, lateral temporal lobe and left parietal lobe showing hemispheric imbalance in information processing. There is a reported case of the development of BDD in a 21 year old male following an inflammatory brain process. Neuroimaging showed the presence of new atrophy in the frontotemporal region.[159][160][161][162][163]
The distinction between the diagnoses of anorexia nervosa, bulimia nervosa and eating disorder not otherwise specified (EDNOS) is often difficult to make as there is considerable overlap between patients diagnosed with these conditions. Seemingly minor changes in a patient's overall behavior or attitude can change a diagnosis from "anorexia: binge-eating type" to bulimia nervosa. It is not unusual for a person with an eating disorder to "move through" various diagnoses as his or her behavior and beliefs change over time.[99]
Treatment for anorexia nervosa tries to address three main areas. 1) Restoring the person to a healthy weight; 2) Treating the psychological disorders related to the illness; 3) Reducing or eliminating behaviours or thoughts that originally led to the disordered eating.[164]
| Cognitive Behavioral Therapies
| ||||
| Rational Emotive Behavior Therapy | Dialectical behavior therapy[182] | Rational Living Therapy | Rational Behavior Therapy | Cognitive Therapy |
Green Red Blue
Purple Blue Purple
Blue Purple Red
Green Purple Green
The long term prognosis of anorexia is more on favorable side. The National Comorbidity Replication Survey was conducted among more than 9,282 participants throughout the United States, the results found that the average duration of anorexia nervosa is 1.7 years. "Contrary to what people may believe, anorexia is not necessarily a chronic illness; in many cases, it runs its course and people get better..."[194]
In cases of adolescent anorexia nervosa that utilize Family treatment 75% of patients have a good outcome and an additional 15% show an intermediate yet more positive outcome.[187] In a five year post treatment follow-up of Maudsley Family Therapy the full recovery rate was between 75% and 90%.[195] Even in severe cases of AN, despite a noted 30% relapse rate after hospitalization, and a lengthy time to recovery ranging from 57–79 months, the full recovery rate was still 76%. There were minimal cases of relapse even at the long term follow-up conducted between 10–15 years.[196]
Anorexia has 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.[197][198] The condition largely affects young adolescent women, with between 15 and 19 years old making up 40% of all cases. Approximately 90% of people with anorexia are female.[199]
The history of anorexia nervosa begins with early descriptions dating from the 16th century and 17th century and the first recognition and description of anorexia nervosa as a disease in the late 19th century.
In the late 19th century, the public attention drawn to "fasting girls" provoked conflict between religion and science. Such cases as Sarah Jacob (the "Welsh Fasting Girl") and Mollie Fancher (the "Brooklyn Enigma") stimulated controversy as experts weighed the claims of complete abstinence from food. Believers referenced the duality of mind and body, while skeptics insisted on the laws of science and material facts of life. Critics accused the fasting girls of hysteria, superstition, and deceit. The progress of secularization and medicalization passed cultural authority from clergy to physicians, transforming anorexia nervosa from revered to reviled.[200]
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