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Eating disorders
Sketch of a person with anorexia
Specialty	Psychiatry
Symptoms	Abnormal eating habits that negatively affect physical or mental health[1]
Complications	Anxiety disorders, depression, substance abuse[2]
Types	Binge eating disorder, anorexia nervosa, bulimia nervosa, pica, rumination disorder, avoidant/restrictive food intake disorder[1]
Causes	Unclear[3]
Risk factors	Gastrointestinal disorders, history of sexual abuse, being a dancer[4][5][6]
Treatment	Counselling, proper diet, normal amount of exercise, medications[2]

An eating disorder is a mental disorder defined by abnormal eating habits that negatively affect a person's physical or mental health.^[1] They include binge eating disorder where people eat a large amount in a short period of time, anorexia nervosa where people eat very little and thus have a low body weight, bulimia nervosa where people eat a lot and then try to rid themselves of the food, pica where people eat non-food items, rumination disorder where people regurgitate food, avoidant/restrictive food intake disorder where people have a lack of interest in food, and a group of other specified feeding or eating disorders.^[1]Anxiety disorders, depression, and substance abuse are common among people with eating disorders.^[2] These disorders do not include obesity.^[1]

The causes of eating disorders are not clear.^[3] Both biological and environmental factors appear to play a role.^[2][3] Cultural idealization of thinness is believed to contribute.^[3] Eating disorders affect about 12 per cent of dancers.^[4] Individuals who have experienced sexual abuse are also more likely to develop eating disorders.^[6] Some disorders such as pica and rumination disorder occur more often in people with intellectual disabilities.^[1] Only one eating disorder can be diagnosed at a given time.^[1]

Treatment can be effective for many eating disorders.^[2] Typically, this involves counselling, a proper diet, a normal amount of exercise, and the reduction of efforts to eliminate food.^[2] Hospitalization may be needed in more serious cases.^[2] Medications may be used to help with some of the associated symptoms.^[2] About 70% of people with anorexia and 50% of people with bulimia recover within five years.^[7] Recovery from binge eating disorder is less clear and estimated at 20% to 60%.^[7] Both anorexia and bulimia increase the risk of death.^[7]

In the developed world binge eating disorder affects about 1.6% of women and 0.8% of men in a given year.^[1] Anorexia affects about 0.4% and bulimia affects about 1.3% of young women in a given year.^[1] Up to 4% of women have anorexia, 2% have bulimia, and 2% have binge eating disorder at some point in time.^[7] Anorexia and bulimia occur nearly ten times more often in females than males.^[1] Typically, they begin in late childhood or early adulthood.^[2] Rates of other eating disorders are not clear.^[1] Rates of eating disorders appear to be lower in less developed countries.^[8]

Classification

Bulimia nervosa is a disorder characterized by binge eating and purging, as well as excessive evaluation of one's self-worth in terms of body weight or shape.^[9] Purging can include self-induced vomiting, over-exercising, and the use of diuretics, enemas, and laxatives. Anorexia nervosa is characterized by extreme food restriction and excessive weight loss, accompanied by the fear of being fat.^[10] The extreme weight loss often causes women and girls who have begun menstruating to stop having menstrual periods, a condition known as amenorrhea. Although amenorrhea was once a required criterion for the disorder, it is no longer required to meet criteria for anorexia nervosa due to its exclusive nature for sufferers who are male, post-menopause, or who do not menstruate for other reasons.^[11] The DSM-5 specifies two subtypes of anorexia nervosa—the restricting type and the binge/purge type. Those who suffer from the restricting type of anorexia nervosa restrict food intake and do not engage in binge eating, whereas those suffering from the binge/purge type lose control over their eating at least occasionally and may compensate for these binge episodes.^[12] The most notable difference between anorexia nervosa binge/purge type and bulimia nervosa is the body weight of the person. Those diagnosed with anorexia nervosa binge/purge type are underweight, while those with bulimia nervosa may have a body weight that falls within the range from normal to obese.^[13][14]

ICD and DSM

These eating disorders are specified as mental disorders in standard medical manuals, such as in the ICD-10,^[15] the DSM-5, or both.

• 
  Anorexia nervosa (AN), characterized by lack of maintenance of a healthy body weight, an obsessive fear of gaining weight or refusal to do so, and an unrealistic perception, or non-recognition of the seriousness, of current low body weight.^[16] Anorexia can cause menstruation to stop, and often leads to bone loss, loss of skin integrity, etc. It greatly stresses the heart, increasing the risk of heart attacks and related heart problems. The risk of death is greatly increased in individuals with this disease.^[17] The most underlining factor researchers are starting to take notice of is that it may not just be a vanity, social, or media issue, but it could also be related to biological and or genetic components.^[18] The DSM-5 contains many changes that better represent patients with these conditions. The DSM-IV required amenorrhea (the absence of the menstrual cycle) to be present in order to diagnose a patient with anorexia.^[19] This is no longer a requirement in the DSM-5.


• 
  Bulimia nervosa (BN), characterized by recurrent binge eating followed by compensatory behaviors such as purging (self-induced vomiting, eating to the point of vomiting, excessive use of laxatives/diuretics, or excessive exercise). Fasting and over-exercising may also be used as a method of purging following a binge.


• 
  Muscle dysmorphia is characterized by appearance preoccupation that one's own body is too small, too skinny, insufficiently muscular, or insufficiently lean. Muscle dysmorphia affects mostly males.


• 
  Binge Eating Disorder (BED), characterized by recurring binge eating at least once a week for over a period of 3 months while experiencing lack of control^[19] and guilt after overeating.^[20] The disorder can develop within individuals of a wide range of ages and socioeconomic classes.^[21][22]
  


• 
  Other Specified Feeding or Eating Disorder (OSFED) is an eating or feeding disorder that does not meet full DSM-5 criteria for AN, BN, or BED. Examples of otherwise-specified eating disorders include individuals with atypical anorexia nervosa, who meet all criteria for AN except being underweight, despite substantial weight loss; atypical bulimia nervosa, who meet all criteria for BN except that bulimic behaviors are less frequent or have not been ongoing for long enough; purging disorder; and night eating syndrome.

Other

• 
  Compulsive overeating (COE), in which individuals habitually graze on large quantities of food rather than binging, as would be typical of binge eating disorder.


• Prader-Willi syndrome


• 
  Diabulimia, characterized by the deliberate manipulation of insulin levels by diabetics in an effort to control their weight.


• Food maintenance, characterized by a set of aberrant eating behaviors of children in foster care.^[23]
  


• 
  Orthorexia nervosa, a term used by Steven Bratman to characterize an obsession with a "pure" diet, in which people develop an obsession with avoiding unhealthy foods to the point where it interferes with a person's life.^[24]
  


• 
  Avoidant/restrictive food intake disorder (ARFID), previously known as selective eating disorder is where the certain foods are limited based on appearance, smell, taste, texture, brand, presentation, or a past negative experience with the food.^[25]
  


• 
  Drunkorexia, commonly characterized by purposely restricting food intake in order to reserve food calories for alcoholic calories, exercising excessively in order to burn calories from drinking, and over-drinking alcohol in order to purge previously consumed food.^[26]
  


• Pregorexia, characterized by extreme dieting and over-exercising in order to control pregnancy weight gain. Undernutrition during pregnancy is associated with low birth weight, coronary heart disease, type 2 diabetes, stroke, hypertension, cardiovascular disease risk, and depression.^[27]
  


• 
  Gourmand syndrome, a rare condition occurring after damage to the frontal lobe, resulting in an obsessive focus on fine foods.^[28]
  

Signs and symptoms

Symptoms and complications vary according to the nature and severity of the eating disorder:^[29]

Some physical symptoms of eating disorders are weakness, fatigue, sensitivity to cold, reduced beard growth in men, reduction in waking erections, reduced libido, weight loss and failure of growth.^[37] Unexplained hoarseness may be a symptom of an underlying eating disorder, as the result of acid reflux, or entry of acidic gastric material into the laryngoesophageal tract. Patients who induce vomiting, such as those with anorexia nervosa, binge eating-purging type or those with purging-type bulimia nervosa are at risk for acid reflux.^{[medical citation needed]}Polycystic ovary syndrome (PCOS) is the most common endocrine disorder to affect women. Though often associated with obesity it can occur in normal weight individuals. PCOS has been associated with binge eating and bulimic behavior.^{[38][39][40][41][42][43]} Other possible manifestations are dry lips,^[44]burning tongue,^[44]parotid gland swelling,^[44] and temporomandibular disorders.^[44]

Pro-ana subculture

Pro-ana refers to the promotion of behaviors related to the eating disorder anorexia nervosa. Several websites promote eating disorders, and can provide a means for individuals to communicate in order to maintain eating disorders. Members of these websites typically feel that their eating disorder is the only aspect of a chaotic life that they can control.^[45] These websites are often interactive and have discussion boards where individuals can share strategies, ideas, and experiences, such as diet and exercise plans that achieve extremely low weights.^[46] A study comparing the personal web-blogs that were pro-eating disorder with those focused on recovery found that the pro-eating disorder blogs contained language reflecting lower cognitive processing, used a more closed-minded writing style, contained less emotional expression and fewer social references, and focused more on eating-related contents than did the recovery blogs.^[47]

Psychopathology

The psychopathology of eating disorders centers around body image disturbance, such as concerns with weight and shape; self-worth being too dependent on weight and shape; fear of gaining weight even when underweight; denial of how severe the symptoms are and a distortion in the way the body is experienced.^[37]

Causes

The causes of eating disorders are not clear.

Many people with eating disorders also have body dysmorphic disorder, altering the way a person sees themself.^[48][49] Studies have found that a high proportion of individuals diagnosed with body dysmorphic disorder also had some type of eating disorder, with 15% of individuals having either anorexia nervosa or bulimia nervosa.^[48] This link between body dysmorphic disorder and anorexia stems from the fact that both BDD and anorexia nervosa are characterized by a preoccupation with physical appearance and a distortion of body image.^[49] There are also many other possibilities such as environmental, social and interpersonal issues that could promote and sustain these illnesses.^[50] Also, the media are oftentimes blamed for the rise in the incidence of eating disorders due to the fact that media images of idealized slim physical shape of people such as models and celebrities motivate or even force people to attempt to achieve slimness themselves. The media are accused of distorting reality, in the sense that people portrayed in the media are either naturally thin and thus unrepresentative of normality or unnaturally thin by forcing their bodies to look like the ideal image by putting excessive pressure on themselves to look a certain way. While past findings have described eating disorders as primarily psychological, environmental, and sociocultural, further studies have uncovered evidence that there is a genetic component.^[51]

Genetics

Numerous studies show a genetic predisposition toward eating disorders.^[52][52][53] Twin studies have found a slight instances of genetic variance when considering the different criterion of both anorexia nervosa and bulimia nervosa as endophenotypes contributing to the disorders as a whole.^[50] A genetic link has been found on chromosome 1 in multiple family members of an individual with anorexia nervosa.^[51] An individual who is a first degree relative of someone who has had or currently has an eating disorder is seven to twelve times more likely to have an eating disorder themselves.^[54] Twin studies also show that at least a portion of the vulnerability to develop eating disorders can be inherited, and there is evidence to show that there is a genetic locus that shows susceptibility for developing anorexia nervosa.^[54] About 50% of eating disorder cases are attributable to genetics.^[55] Other cases are due to external reasons or developmental problems.^[56] There are also other neurobiological factors at play tied to emotional reactivity and impulsivity that could lead to binging and purging behaviors.^[57]

Epigenetics mechanisms are means by which environmental effects alter gene expression via methods such as DNA methylation; these are independent of and do not alter the underlying DNA sequence. They are heritable, but also may occur throughout the lifespan, and are potentially reversible. Dysregulation of dopaminergic neurotransmission due to epigenetic mechanisms has been implicated in various eating disorders.^[58] Other candidate genes for epigenetic studies in eating disorders include leptin, pro-opiomelanocortin (POMC) and brain-derived neurotrophic factor (BDNF).^[59]

Psychological

Eating disorders are classified as Axis I^[60] disorders in the Diagnostic and Statistical Manual of Mental Health Disorders (DSM-IV) published by the American Psychiatric Association. There are various other psychological issues that may factor into eating disorders, 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.^[61] Some people have a previous disorder which may increase their vulnerability to developing an eating disorder.^[62][63][64] Some develop them afterwards.^[65] The severity and type of eating disorder symptoms have been shown to affect comorbidity.^[66] The DSM-IV should not be used by laypersons to diagnose themselves even when used by professionals there has been considerable controversy over the diagnostic criteria used for various diagnoses, including eating disorders. There has been controversy over various editions of the DSM including the latest edition, DSM-V, due in May 2013.^{[67][68][69][70][71]}

Cognitive attentional bias issues

Attentional bias may have an effect on eating disorders. Many studies have been performed to test this theory.

Personality traits

There are various childhood personality traits associated with the development of eating disorders.^[86] During adolescence these traits may become intensified due to a variety of physiological and cultural influences such as the hormonal changes associated with puberty, stress related to the approaching demands of maturity and socio-cultural influences and perceived expectations, especially in areas that concern body image. Eating disorders have been associated with a fragile sense of self and with disordered mentalization.^[87] Many personality traits have a genetic component and are highly heritable. Maladaptive levels of certain traits may be acquired as a result of anoxic or traumatic brain injury, neurodegenerative diseases such as Parkinson's disease, neurotoxicity such as lead exposure, bacterial infection such as Lyme disease or parasitic infection such as Toxoplasma gondii as well as hormonal influences. While studies are still continuing via the use of various imaging techniques such as fMRI; these traits have been shown to originate in various regions of the brain^[88] such as the amygdala^[89][90] and the prefrontal cortex.^[91] Disorders in the prefrontal cortex and the executive functioning system have been shown to affect eating behavior.^[92][93]

Celiac disease

People with gastrointestinal disorders may be more risk of developing disordered eating practices than the general population, principally restrictive eating disturbances.^[5] An association of anorexia nervosa with celiac disease has been found.^[94] The role that gastrointestinal symptoms play in the development of eating disorders seems rather complex. Some authors report that unresolved symptoms prior to gastrointestinal disease diagnosis may create a food aversion in these persons, causing alterations to their eating patterns. Other authors report that greater symptoms throughout their diagnosis led to greater risk. It has been documented that some people with celiac disease, irritable bowel syndrome or inflammatory bowel disease who are not conscious about the importance of strictly following their diet, choose to consume their trigger foods to promote weight loss. On the other hand, individuals with good dietary management may develop anxiety, food aversion and eating disorders because of concerns around cross contamination of their foods.^[5] Some authors suggest that medical professionals should evaluate the presence of an unrecognized celiac disease in all people with eating disorder, especially if they present any gastrointestinal symptom (such as decreased appetite, abdominal pain, bloating, distension, vomiting, diarrhea or constipation), weight loss, or growth failure; and also routinely ask celiac patients about weight or body shape concerns, dieting or vomiting for weight control, to evaluate the possible presence of eating disorders,^[94] specially in women.^[95]

Environmental influences

Child maltreatment

Child abuse which encompasses physical, psychological and sexual abuse, as well as neglect has been shown to approximately triple the risk of an eating disorder.^[96] Sexual abuse appears to about double the risk of bulimia; however, the association is less clear for anorexia.^[96]

Social isolation

Social isolation has been shown to have a deleterious effect on an individual's physical and emotional well-being. Those that are socially isolated have a higher mortality rate in general as compared to individuals that have established social relationships. This effect on mortality is markedly increased in those with pre-existing medical or psychiatric conditions, and has been especially noted in cases of coronary heart disease. "The magnitude of risk associated with social isolation is comparable with that of cigarette smoking and other major biomedical and psychosocial risk factors." (Brummett et al.)

Social isolation can be inherently stressful, depressing and anxiety-provoking. In an attempt to ameliorate these distressful feelings an individual may engage in emotional eating in which food serves as a source of comfort. The loneliness of social isolation and the inherent stressors thus associated have been implicated as triggering factors in binge eating as well.^{[97][98][99][100]}

Waller, Kennerley and Ohanian (2007) argued that both bingeing–vomiting and restriction are emotion suppression strategies, but they are just utilized at different times. For example, restriction is used to pre-empt any emotion activation, while bingeing–vomiting is used after an emotion has been activated.^[101]

Parental influence

Parental influence has been shown to be an intrinsic component in the development of eating behaviors of children. This influence is manifested and shaped by a variety of diverse factors such as familial genetic predisposition, dietary choices as dictated by cultural or ethnic preferences, the parents' own body shape and eating patterns, the degree of involvement and expectations of their children's eating behavior as well as the interpersonal relationship of parent and child. This is in addition to the general psychosocial climate of the home and the presence or absence of a nurturing stable environment. It has been shown that maladaptive parental behavior has an important role in the development of eating disorders. As to the more subtle aspects of parental influence, it has been shown that eating patterns are established in early childhood and that children should be allowed to decide when their appetite is satisfied as early as the age of two. A direct link has been shown between obesity and parental pressure to eat more.

Coercive tactics in regard to diet have not been proven to be efficacious in controlling a child's eating behavior. Affection and attention have been shown to affect the degree of a child's finickiness and their acceptance of a more varied diet.^{[102][103][104][105][106][107]}

Adams and Crane (1980), have shown that parents are influenced by stereotypes that influence their perception of their child's body. The conveyance of these negative stereotypes also affects the child's own body image and satisfaction.^[108]Hilde Bruch, a pioneer in the field of studying eating disorders, asserts that anorexia nervosa often occurs in girls who are high achievers, obedient, and always trying to please their parents. Their parents have a tendency to be over-controlling and fail to encourage the expression of emotions, inhibiting daughters from accepting their own feelings and desires. Adolescent females in these overbearing families lack the ability to be independent from their families, yet realize the need to, often resulting in rebellion. Controlling their food intake may make them feel better, as it provides them with a sense of control.^[109]

Peer pressure

In various studies such as one conducted by The McKnight Investigators, peer pressure was shown to be a significant contributor to body image concerns and attitudes toward eating among subjects in their teens and early twenties.

Eleanor Mackey and co-author, Annette M. La Greca of the University of Miami, studied 236 teen girls from public high schools in southeast Florida. "Teen girls' concerns about their own weight, about how they appear to others and their perceptions that their peers want them to be thin are significantly related to weight-control behavior", says psychologist Eleanor Mackey of the Children's National Medical Center in Washington and lead author of the study. "Those are really important."

According to one study, 40% of 9- and 10-year-old girls are already trying to lose weight.^[110] Such dieting is reported to be influenced by peer behavior, with many of those individuals on a diet reporting that their friends also were dieting. The number of friends dieting and the number of friends who pressured them to diet also played a significant role in their own choices.^{[111][112][113][114]}

Elite athletes have a significantly higher rate in eating disorders. Female athletes in sports such as gymnastics, ballet, diving, etc. are found to be at the highest risk among all athletes. Women are more likely than men to acquire an eating disorder between the ages of 13–30. 0–15% of those with bulimia and anorexia are men.^[115]

Cultural pressure

There is a cultural emphasis on thinness which is especially pervasive in western society. A child's perception of external pressure to achieve the ideal body that is represented by the media predicts the child's body image dissatisfaction, body dysmorphic disorder and an eating disorder.^[116] "The cultural pressure on men and women to be 'perfect' is an important predisposing factor for the development of eating disorders".^[117][118] Further, when women of all races base their evaluation of their self upon what is considered the culturally ideal body, the incidence of eating disorders increases.^[119] Eating disorders are becoming more prevalent in non-Western countries where thinness is not seen as the ideal, showing that social and cultural pressures are not the only causes of eating disorders.^[120] For example, observations of anorexia in all of the non-Western regions of the world point to the disorder not being "culture-bound" as once thought.^[121] However, studies on rates of bullimia suggest that it might be culturally bound. In non-Western countries, bulimia is less prevalent than anorexia, but these non-Western countries where it is observed can be said to have probably or definitely been influenced or exposed to Western culture and ideology.^[122]

Socioeconomic status (SES) has been viewed as a risk factor for eating disorders, presuming that possessing more resources allows for an individual to actively choose to diet and reduce body weight.^[123] Some studies have also shown a relationship between increasing body dissatisfaction with increasing SES.^[124] However, once high socioeconomic status has been achieved, this relationship weakens and, in some cases, no longer exists.^[121]

The media plays a major role in the way in which people view themselves. Countless magazine ads and commercials depict thin celebrities like Lindsay Lohan, Nicole Richie, Victoria Beckham and Mary Kate Olsen, who appear to gain nothing but attention from their looks. Society has taught people that being accepted by others is necessary at all costs.^[125] Unfortunately this has led to the belief that in order to fit in one must look a certain way. Televised beauty competitions such as the Miss America Competition contribute to the idea of what it means to be beautiful because competitors are evaluated on the basis of their opinion.^[126]

In addition to socioeconomic status being considered a cultural risk factor so is the world of sports. Athletes and eating disorders tend to go hand in hand, especially the sports where weight is a competitive factor. Gymnastics, horse back riding, wrestling, body building, and dancing are just a few that fall into this category of weight dependent sports. Eating disorders among individuals that participate in competitive activities, especially women, often lead to having physical and biological changes related to their weight that often mimic prepubescent stages. Oftentimes as women's bodies change they lose their competitive edge which leads them to taking extreme measures to maintain their younger body shape. Men often struggle with binge eating followed by excessive exercise while focusing on building muscle rather than losing fat, but this goal of gaining muscle is just as much an eating disorder as obsessing over thinness. The following statistics taken from Susan Nolen-Hoeksema's book, (ab)normal psychology, show the estimated percentage of athletes that struggle with eating disorders based on the category of sport.

• Aesthetic sports (dance, figure skating, gymnastics) – 35%


• Weight dependent sports (judo, wrestling) – 29%


• Endurance sports (cycling, swimming, running) – 20%


• Technical sports (golf, high jumping) – 14%


• Ball game sports (volleyball, soccer) – 12%

Although most of these athletes develop eating disorders to keep their competitive edge, others use exercise as a way to maintain their weight and figure. This is just as serious as regulating food intake for competition. Even though there is mixed evidence showing at what point athletes are challenged with eating disorders, studies show that regardless of competition level all athletes are at higher risk for developing eating disorders that non-athletes, especially those that participate in sports where thinness is a factor.^[127]

Pressure from society is also seen within the homosexual community. Homosexual men are at greater risk of eating disorder symptoms than heterosexual men.^[128] Within the gay culture, muscularity gives the advantages of both social and sexual desirability and also power.^[129] These pressures and ideas that another homosexual male may desire a mate who is thinner or muscular can possibly lead to eating disorders. The higher eating disorder symptom score reported, the more concern about how others perceive them and the more frequent and excessive exercise sessions occur.^[129] High levels of body dissatisfaction are also linked to external motivation to working out and old age; however, having a thin and muscular body occurs within younger homosexual males than older.^[128][129]

It is important to realize some of the limitations and challenges of many studies that try to examine the roles of culture, ethnicity, and SES. For starters, most of the cross-cultural studies use definitions from the DSM-IV-TR, which has been criticized as reflecting a Western cultural bias. Thus, assessments and questionnaires may not be constructed to detect some of the cultural differences associated with different disorders. Also, when looking at individuals in areas potentially influenced by Western culture, few studies have attempted to measure how much an individual has adopted the mainstream culture or retained the traditional cultural values of the area. Lastly, the majority of the cross-cultural studies on eating disorders and body image disturbances occurred in Western nations and not in the countries or regions being examined.^[130]

While there are many influences to how an individual processes their body image, the media does play a major role. Along with the media, parental influence, peer influence, and self-efficacy beliefs also play a large role in an individual's view of themselves. The way the media presents images can have a lasting effect on an individual's perception of their body image. Eating disorders are a worldwide issue and while women are more likely to be affected by an eating disorder it still affects both genders (Schwitzer 2012). The media influences eating disorders whether shown in a positive or negative light, it then has a responsibility to use caution when promoting images that projects an ideal that many turn to eating disorders to attain.^[131]

To try to address unhealthy body image in the fashion world, in 2015, France passed a law requiring models to be declared healthy by a doctor to participate in fashion shows. It also requires re-touched images to be marked as such in magazines.^[132]

There is a relationship between “thin ideal” social media content and body dissatisfaction and eating disorders among young adult women, especially in the Western hemisphere.^[133] New research points to an “internalization” of distorted images online, as well as negative comparisons among young adult women.^[134] Most studies have been based in the U.S, the U.K, and Australia, these are places where the thin ideal is strong among women, as well as the strive for the “perfect” body.^[134]

In addition to mere media exposure, there is an online “pro-eating disorder” community. Through personal blogs and Twitter, this community promotes eating disorders as a “lifestyle”, and continuously posts pictures of emaciated bodies, and tips on how to stay thin. The hashtag “#proana” (pro-anorexia), is a product of this community,^[135] as well as images promoting weight loss, tagged with the term “thinspiration”. According to social comparison theory, young women have a tendency to compare their appearance to others, which can result in a negative view of their own bodies and altering of eating behaviors, that in turn can develop disordered eating behaviors.^[136]

When body parts are isolated and displayed in the media as objects to be looked at, it is called objectification, and women are affected most by this phenomenon. Objectification increases self-objectification, where women judge their own body parts as a mean of praise and pleasure for others. There is a significant link between self-objectification, body dissatisfaction, and disordered eating, as the beauty ideal is altered through social media.^[133]

Mechanisms

• 
  Biochemical: Eating behavior is a complex process controlled by the neuroendocrine system, of which the Hypothalamus-pituitary-adrenal-axis (HPA axis) is a major component. Dysregulation of the HPA axis has been associated with eating disorders,^[137][138] such as irregularities in the manufacture, amount or transmission of certain neurotransmitters, hormones^[139] or neuropeptides^[140] and amino acids such as homocysteine, elevated levels of which are found in AN and BN as well as depression.^[141]
  
  
  • 
    Serotonin: a neurotransmitter involved in depression also has an inhibitory effect on eating behavior.^{[142][143][144][145][146]}
    
  
  
  • 
    Norepinephrine is both a neurotransmitter and a hormone; abnormalities in either capacity may affect eating behavior.^[147][148]
    
  
  
  • 
    Dopamine: which in addition to being a precursor of norepinephrine and epinephrine is also a neurotransmitter which regulates the rewarding property of food.^[149][150]
    
  
  
  • 
    Neuropeptide Y also known as NPY is a hormone that encourages eating and decreases metabolic rate.^[151] Blood levels of NPY are elevated in patients with anorexia nervosa, and studies have shown that injection of this hormone into the brain of rats with restricted food intake increases their time spent running on a wheel. Normally the hormone stimulates eating in healthy patients, but under conditions of starvation it increases their activity rate, probably to increase the chance of finding food.^[151] The increased levels of NPY in the blood of patients with eating disorders can in some ways explain the instances of extreme over-exercising found in most anorexia nervosa patients.
  
  
  
  


• 
  Leptin and ghrelin: leptin is a hormone produced primarily by the fat cells in the body; it has an inhibitory effect on appetite by inducing a feeling of satiety. Ghrelin is an appetite inducing hormone produced in the stomach and the upper portion of the small intestine. Circulating levels of both hormones are an important factor in weight control. While often associated with obesity, both hormones and their respective effects have been implicated in the pathophysiology of anorexia nervosa and bulimia nervosa.^[152] Leptin can also be used to distinguish between constitutional thinness found in a healthy person with a low BMI and an individual with anorexia nervosa.^[50][153]
  


• Gut bacteria and immune system: studies have shown that a majority of patients with anorexia and bulimia nervosa have elevated levels of autoantibodies that affect hormones and neuropeptides that regulate appetite control and the stress response. There may be a direct correlation between autoantibody levels and associated psychological traits.^[154][155] Later study revealed that autoantibodies reactive with alpha-MSH are, in fact, generated against ClpB, a protein produced by certain gut bacteria e.g. Escherichia coli. ClpB protein was identified as a conformational antigen-mimetic of alpha-MSH. In patients with eating disorders plasma levels of anti-ClpB IgG and IgM correalated with patients' psychological traits^[156]
  


• Infection: PANDAS, is an abbreviation for Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections. Children with PANDAS "have obsessive-compulsive disorder (OCD) and/or tic disorders such as Tourette syndrome, and in whom symptoms worsen following infections such as "strep throat" and scarlet fever". (NIMH) There is a possibility that PANDAS may be a precipitating factor in the development of anorexia nervosa in some cases, (PANDAS AN).^[157]
  


• 
  Lesions: studies have shown that lesions to the right frontal lobe or temporal lobe can cause the pathological symptoms of an eating disorder.^{[158][159][160]}
  


• 
  Tumors: tumors in various regions of the brain have been implicated in the development of abnormal eating patterns.^{[161][162][163][164][165]}
  


• Brain calcification: a study highlights a case in which prior calcification of the right thalumus may have contributed to development of anorexia nervosa.^[166]
  


• 
  somatosensory homunculus: is the representation of the body located in the somatosensory cortex, first described by renowned neurosurgeon Wilder Penfield. The illustration was originally termed "Penfield's Homunculus", homunculus meaning little man. "In normal development this representation should adapt as the body goes through its pubertal growth spurt. However, in AN it is hypothesized that there is a lack of plasticity in this area, which may result in impairments of sensory processing and distortion of body image". (Bryan Lask, also proposed by VS Ramachandran)


• 
  Obstetric complications: There have been studies done which show maternal smoking, obstetric and perinatal complications such as maternal anemia, very pre-term birth (less than 32 weeks), being born small for gestational age, neonatal cardiac problems, preeclampsia, placental infarction and sustaining a cephalhematoma at birth increase the risk factor for developing either anorexia nervosa or bulimia nervosa. Some of this developmental risk as in the case of placental infarction, maternal anemia and cardiac problems may cause intrauterine hypoxia, umbilical cord occlusion or cord prolapse may cause ischemia, resulting in cerebral injury, the prefrontal cortex in the fetus and neonate is highly susceptible to damage as a result of oxygen deprivation which has been shown to contribute to executive dysfunction, ADHD, and may affect personality traits associated with both eating disorders and comorbid disorders such as impulsivity, mental rigidity and obsessionality. The problem of perinatal brain injury, in terms of the costs to society and to the affected individuals and their families, is extraordinary. (Yafeng Dong, PhD)^{[167][168][169][170][171][172][173][174][175][176][177]}
  


• Symptom of starvation: Evidence suggests that the symptoms of eating disorders are actually symptoms of the starvation itself, not of a mental disorder. In a study involving thirty-six healthy young men that were subjected to semi-starvation, the men soon began displaying symptoms commonly found in patients with eating disorders.^[151][178] In this study, the healthy men ate approximately half of what they had become accustomed to eating and soon began developing symptoms and thought patterns (preoccupation with food and eating, ritualistic eating, impaired cognitive ability, other physiological changes such as decreased body temperature) that are characteristic symptoms of anorexia nervosa.^[151] The men used in the study also developed hoarding and obsessive collecting behaviors, even though they had no use for the items, which revealed a possible connection between eating disorders and obsessive compulsive disorder.^[151]
  

Diagnosis

The initial diagnosis should be made by a competent medical professional. "The medical history is the most powerful tool for diagnosing eating disorders"(American Family Physician).^[179] There are many medical disorders that mimic eating disorders and comorbid psychiatric disorders. All organic causes should be ruled out prior to a diagnosis of an eating disorder or any other psychiatric disorder. In the past 30 years eating disorders have become increasingly conspicuous and it is uncertain whether the changes in presentation reflect a true increase.^{[citation needed]} Anorexia nervosa and bulimia nervosa are the most clearly defined subgroups of a wider range of eating disorders. Many patients present with subthreshold expressions of the two main diagnoses: others with different patterns and symptoms.^[180]

Medical

The diagnostic workup typically includes complete medical and psychosocial history and follows a rational and formulaic approach to the diagnosis. Neuroimaging using fMRI, MRI, PET and SPECT scans have been used to detect cases in which a lesion, tumor or other organic condition has been either the sole causative or contributory factor in an eating disorder. "Right frontal intracerebral lesions with their close relationship to the limbic system could be causative for eating disorders, we therefore recommend performing a cranial MRI in all patients with suspected eating disorders" (Trummer M et al. 2002), "intracranial pathology should also be considered however certain is the diagnosis of early-onset anorexia nervosa. Second, neuroimaging plays an important part in diagnosing early-onset anorexia nervosa, both from a clinical and a research prospective".(O'Brien et al. 2001).^[160][181]

Psychological

After ruling out organic causes and the initial diagnosis of an eating disorder being made by a medical professional, a trained mental health professional aids in the assessment and treatment of the underlying psychological components of the eating disorder and any comorbid psychological conditions. The clinician conducts a clinical interview and may employ various psychometric tests. Some are general in nature while others were devised specifically for use in the assessment of eating disorders. Some of the general tests that may be used are the Hamilton Depression Rating Scale^[188] and the Beck Depression Inventory.^[189][190] longitudinal research showed that there is an increase in chance that a young adult female would develop bulimia due to their current psychological pressure and as the person ages and matures, their emotional problems change or are resolved and then the symptoms decline.^[191]

Differential diagnoses

There are multiple medical conditions which may be misdiagnosed as a primary psychiatric disorder, complicating or delaying treatment. These may have a synergistic effect on conditions which mimic an eating disorder or on a properly diagnosed eating disorder.

• 
  Lyme disease which is known as the "great imitator", as it may present as a variety of psychiatric or neurological disorders including anorexia nervosa.^[192][193]
  


• 
  Gastrointestinal diseases,^[5] such as celiac disease, Crohn's disease, peptic ulcer, eosinophilic esophagitis^[94] or non-celiac gluten sensitivity,^[194] among others. Celiac disease is also known as the "great imitator", because it may involve several organs and cause an extensive variety of non-gastrointestinal symptoms, such as psychiatric and neurological disorders,^{[195][196][197]} including anorexia nervosa.^[94]
  


• 
  Addison's Disease is a disorder of the adrenal cortex which results in decreased hormonal production. Addison's disease, even in subclinical form may mimic many of the symptoms of anorexia nervosa.^[198]
  


• 
  Gastric adenocarcinoma is one of the most common forms of cancer in the world. Complications due to this condition have been misdiagnosed as an eating disorder.^[199]
  


• 
  Hypothyroidism, hyperthyroidism, hypoparathyroidism and hyperparathyroidism may mimic some of the symptoms of, can occur concurrently with, be masked by or exacerbate an eating disorder.^{[200][201][202][203][204][205][206][207]}
  


• 
  Toxoplasma seropositivity: even in the absence of symptomatic toxoplasmosis, toxoplasma gondii exposure has been linked to changes in human behavior and psychiatric disorders including those comorbid with eating disorders such as depression. In reported case studies the response to antidepressant treatment improved only after adequate treatment for toxoplasma.^[208]
  


• 
  Neurosyphilis: It is estimated that there may be up to one million cases of untreated syphilis in the US alone. "The disease can present with psychiatric symptoms alone, psychiatric symptoms that can mimic any other psychiatric illness". Many of the manifestations may appear atypical. Up to 1.3% of short term psychiatric admissions may be attributable to neurosyphilis, with a much higher rate in the general psychiatric population. (Ritchie, M Perdigao J,)^[209]
  


• 
  Dysautonomia: a wide variety of autonomic nervous system (ANS) disorders may cause a wide variety of psychiatric symptoms including anxiety, panic attacks and depression. Dysautonomia usually involves failure of sympathetic or parasympathetic components of the ANS system but may also include excessive ANS activity. Dysautonomia can occur in conditions such as diabetes and alcoholism.

Psychological disorders which may be confused with an eating disorder, or be co-morbid with one:

• 
  Emetophobia is an anxiety disorder characterized by an intense fear of vomiting. A person so afflicted may develop rigorous standards of food hygiene, such as not touching food with their hands. They may become socially withdrawn to avoid situations which in their perception may make them vomit. Many who suffer from emetophobia are diagnosed with anorexia or self-starvation. In severe cases of emetophobia they may drastically reduce their food intake.^[210][211]
  


• 
  Phagophobia is an anxiety disorder characterized by a fear of eating, it is usually initiated by an adverse experience while eating such as choking or vomiting. Persons with this disorder may present with complaints of pain while swallowing.^[212]
  


• 
  Body dysmorphic disorder (BDD) is listed as a somatoform disorder that affects up to 2% of the population. BDD is characterized by excessive rumination over an actual or perceived physical flaw. BDD has been diagnosed equally among men and women. While BDD has been misdiagnosed as anorexia nervosa, it also occurs comorbidly in 39% of eating disorder cases. BDD is a chronic and debilitating condition which may lead to social isolation, major depression and 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 a new atrophy in the frontotemporal region.^{[213][214][215][216]}
  

Prevention

Prevention aims to promote a healthy development before the occurrence of eating disorders. It also intends early identification of an eating disorder before it is too late to treat. Children as young as ages 5–7 are aware of the cultural messages regarding body image and dieting. Prevention comes in bringing these issues to the light. The following topics can be discussed with young children (as well as teens and young adults).

• Emotional Bites: a simple way to discuss emotional eating is to ask children about why they might eat besides being hungry. Talk about more effective ways to cope with emotions, emphasizing the value of sharing feelings with a trusted adult.


• Say No to Teasing: another concept is to emphasize that it is wrong to say hurtful things about other people's body sizes.


• Body Talk: emphasize the importance of listening to one's body. That is, eating when you are hungry (not starving) and stopping when you are satisfied (not stuffed). Children intuitively grasp these concepts.


• Fitness Comes in All Sizes: educate children about the genetics of body size and the normal changes occurring in the body. Discuss their fears and hopes about growing bigger. Focus on fitness and a balanced diet.

Internet and modern technologies provide new opportunities for prevention. On-line programs have the potential to increase the use of prevention programs. The development and practice of prevention programs via on-line sources make it possible to reach a wide range of people at minimal cost.^[217] Such an approach can also make prevention programs to be sustainable.

Treatment

Treatment varies according to type and severity of eating disorder, and usually more than one treatment option is utilized.^[218] Family doctors play an important role in early treatment of people with eating disorders by encouraging those who are also reluctant to see a psychiatrist.^[219] Treatment can take place in a variety of different settings such as community programs, hospitals, day programs, and groups.^[220] The American Psychiatric Association (APA) recommends a team approach to treatment of eating disorders. The members of the team are usually a psychiatrist, therapist, and registered dietitian, but other clinicians may be included.^[221]

That said, some treatment methods are:

• 
  Cognitive behavioral therapy (CBT),^{[222][223][224]} which postulates that an individual's feelings and behaviors are caused by their own thoughts instead of external stimuli such as other people, situations or events; the idea is to change how a person thinks and reacts to a situation even if the situation itself does not change. See Cognitive behavioral treatment of eating disorders.
  
  
  
  • 
    Acceptance and commitment therapy: a type of CBT^[225]
    
  
  
  • 
    Cognitive Remediation Therapy (CRT), a set of cognitive drills or compensatory interventions designed to enhance cognitive functioning.^{[226][227][228][229]}
    
  
  
  
  


• 
  Dialectical behavior therapy^[230]
  


• 
  Family therapy^[231] including "conjoint family therapy" (CFT), "separated family therapy" (SFT) and Maudsley Family Therapy.^[232][233]
  


• 
  Behavioral therapy: focuses on gaining control and changing unwanted behaviors.^[234]
  


• 
  Interpersonal psychotherapy (IPT)^[235]
  


• 
  Cognitive Emotional Behaviour Therapy (CEBT)^[236]
  


• Music Therapy


• Recreation Therapy


• 
  Art therapy^[237]
  


• Nutrition counseling^[238] and Medical nutrition therapy^{[239][240][241]}
  


• Medication: Orlistat is used in obesity treatment. Olanzapine seems to promote weight gain as well as the ability to ameliorate obsessional behaviors concerning weight gain. zinc supplements have been shown to be helpful, and cortisol is also being investigated.^{[242][243][244][245][246][247]}
  


• 
  Self-help and guided self-help have been shown to be helpful in AN, BN and BED;^{[224][248][249][250]} this includes support groups and self-help groups such as Eating Disorders Anonymous and Overeaters Anonymous.^[251][252]
  


• Psychoanalysis


• Inpatient care

There are few studies on the cost-effectiveness of the various treatments.^[253] Treatment can be expensive;^[254][255] due to limitations in health care coverage, people hospitalized with anorexia nervosa may be discharged while still underweight, resulting in relapse and rehospitalization.^[256]

For children with anorexia, the only well-established treatment is the family treatment-behavior.^[257] For other eating disorders in children, however, there is no well-established treatments, though family treatment-behavior has been used in treating bulimia.^[257]

Outcomes

Outcome estimates are complicated by non-uniform criteria used by various studies, but for anorexia nervosa, bulimia nervosa, and binge eating disorder, there seems to be general agreement that full recovery rates are in the 50% to 85% range, with larger proportions of people experiencing at least partial remission.^{[251][258][259][260]} The outcomes of eating disorders (ED) vary among the cases. For many, it can be a lifelong struggle or it can be overcome within months. In the United States, twenty million women and ten million men have an eating disorder at least once in their lifetime.^[261] The mortality rate for those with anorexia nervosa is 5.4 per 1000 individuals per year. Roughly 1.3 deaths were due to suicide. A person who is or had been in an inpatient setting had a rate of 4.6 deaths per 1000. Of individuals with bulimia nervosa about 2 persons per 1000 persons die per year and among those with EDNOS about 3.3 per 1000 people die per year.^[262]

• 
  Miscarriages: Pregnant women with a Binge Eating Disorder have shown to have a greater chance of having a miscarriage compared to pregnant women with any other eating disorders. According to a study done, out of a group of pregnant women being evaluated, 46.7% of the pregnancies ended with a miscarriage in women that were diagnosed with BED, with 23.0% in the control. In the same study, 21.4% of women diagnosed with Bulimia Nervosa had their pregnancies end with miscarriages and only 17.7% of the controls.^[263]
  


• 
  Relapse: An individual who is in remission from BN and EDNOS (Eating Disorder Not Otherwise Specified) is at a high risk of falling back into the habit of self-harm. Factors such as high stress regarding their job, pressures from society, as well as other occurrences that inflict stress on a person, can push a person back to what they feel will ease the pain. A study tracked a group of selected people that were either diagnosed with BN or EDNOS for 60 months. After the 60 months were complete, the researchers recorded whether or not the patients were suffering from a relapse. The results found that the probability of a person previously diagnosed with EDNOS had a 41% chance of relapsing; a person with BN had a 47% chance.^[264]
  


• 
  Attachment insecurity: People who are showing signs of attachment anxiety will most likely have trouble communicating their emotional status as well as having trouble seeking effective social support. Signs that a person has adopted this symptom include not showing recognition to their caregiver or when he/she is feeling pain. In a clinical sample, it is clear that at the pretreatment step of a patient's recovery, more severe eating disorder symptoms directly corresponds to higher attachment anxiety. The more this symptom increases, the more difficult it is to achieve eating disorder reduction prior to treatment.^[265]
  

Anorexia Nervosa symptoms include the increasing chance of getting osteoporosis. This disease causes the bones of an individual to become brittle, weak, and low in density. Thinning of the hair as well as dry hair and skin are also very common. The muscles of the heart will also start to change if no treatment is inflicted on the patient. This causes the heart to have an abnormally slow heart rate along with low blood pressure. Heart failure becomes a major consideration when this begins to occur. Muscles throughout the body begin to lose their strength. This will cause the individual to begin feeling faint, drowsy, and weak. Along with these symptoms, the body will begin to grow a layer of hair called lanugo. The human body does this in response to the lack of heat and insulation due to the low percentage of body fat.^[261]

Bulimia nervosa symptoms include heart problems like an irregular heartbeat that can lead to heart failure and death may occur. This occurs because of the electrolyte imbalance that is a result of the constant binge and purge process. The probability of a gastric rupture increases. A gastric rupture is when there is a sudden rupture of the stomach lining that can be fatal.The acids that are contained in the vomit can cause a rupture in the esophagus as well as tooth decay. As a result, to laxative abuse, irregular bowel movements may occur along with constipation. Sores along the lining of the stomach called peptic ulcers begin to appear and the chance of developing pancreatitis increases.^[261]

Binge eating symptoms include high blood pressure, which can cause heart disease if it is not treated. Many patients recognize an increase in the levels of cholesterol. The chance of being diagnosed with gallbladder disease increases, which affects an individual's digestive tract.^[261]

Epidemiology

Deaths due to eating disorders per million persons in 2012 .mw-parser-output .refbegin{font-size:90%;margin-bottom:0.5em}.mw-parser-output .refbegin-hanging-indents>ul{list-style-type:none;margin-left:0}.mw-parser-output .refbegin-hanging-indents>ul>li,.mw-parser-output .refbegin-hanging-indents>dl>dd{margin-left:0;padding-left:3.2em;text-indent:-3.2em;list-style:none}.mw-parser-output .refbegin-100{font-size:100%}

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Eating disorders result in about 7,000 deaths a year as of 2010, making them the mental illnesses with the highest mortality rate.^[266]

One study in the United States found a higher rate in college students who are transgender.^[267]

Economics

• Total costs in USA for hospital stays involving eating disorders rose from $165 million in 1999–2000 to $277 million in 2008–2009; this was a 68% increase. The mean cost per discharge of a person with an eating disorder rose by 29% over the decade, from $7,300 to $9,400.


• Over the decade, hospitalizations involving eating disorders increased among all age groups. The greatest increases occurred among those 45 to 65 years of age (an 88% increase), followed by hospitalizations among people younger than 12 years of age (a 72% increase).


• The majority of eating disorder inpatients were female. During 2008–2009, 88% of cases involved females, and 12% were males.^{[medical citation needed]} The report also showed a 53% increase in hospitalizations for males with a principal diagnosis of an eating disorder, from 10% to 12% over the decade.

See also

• Weight phobia


• EDNOS

References

External links

Wikiquote has quotations related to: Eating disorder

• 
  Eating disorder at Curlie