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There are many causes of eating disorders, including biological, psychological and/or environmental abnormalities. Many people with eating disorders suffer also from body dysmorphic disorder, altering the way a person sees himself or herself.[citation needed] There are also many other possibilities such as environmental, social and interpersonal issues that could promote and sustain these illnesses.[34][full citation needed] 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.[35] Biological__ Genetic: Numerous studies have been undertaken that show a possible genetic predisposition toward eating disorders as a result of Mendelian inheritance.[36][36][37] Epigenetics: Epigenetic 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.[38] "We conclude that epigenetic mechanisms may contribute to the known alterations of ANP homeostasis in women with eating disorders."[38][39] 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,[40][41] such as irregularities in the manufacture, amount or transmission of certain neurotransmitters, hormones[42] or neuropeptides[43] and amino acids such as homocysteine, elevated levels of which are found in AN and BN as well as depression.[44] serotonin: a neurotransmitter involved in depression also has an inhibitory effect on eating behavior.[45][46][47][48][49] norepinephrine is both a neurotransmitter and a hormone; abnormalities in either capacity may affect eating behavior.[50][51] dopamine: which in addition to being a precursor of norepinephrine and epinephrine is also a neurotransmitter which regulates the rewarding property of food.[52][53] 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.[54] 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.[55][56] 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).[57] lesions: studies have shown that lesions to the right frontal lobe or temporal lobe can cause the pathological symptoms of an eating disorder.[58][59][60] tumors: tumors in various regions of the brain have been implicated in the development of abnormal eating patterns.[61][62][63][64][65] brain calcification: a study highlights a case in which prior calcification of the right thalumus may have contributed to development of anorexia nervosa.[66] 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 (32<wks.), 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)[67][68][69][70][71][72][73][74][75][76][77] Psychological__ Eating disorders are classified as Axis I[78] 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.[79] Some people have a previous disorder which may increase their vulnerability to developing an eating disorder.[80][81][82] Some develop them afterwards.[83] The severity and type of eating disorder symptoms have been shown to affect comorbidity.[84] 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.[85][86][87][88][89] Cognitive Attentional bias issues__ Attentional bias may have an effect on eating disorders. Many studies have been performed to test this theory. (Shafran, Lee, Cooper, Palmer & Fairburn (2007), Veenstra and de Jong (2012) and Smeets, Jansen, & Roefs (2005)). Evidence of the Effect of Attentional Bias on Eating Disorders Shafran, Lee, Cooper, Palmer and Fairburn (2007) studied the effect of attentional bias on eating disorders in women with anorexia, bulimia, and ED-NOS (Eating Disorder Not Otherwise Specified) compared to a control group and found that those affected by an eating disorder were quicker to identify "bad" eating scenarios than "good" ones. Attentional Bias in Anorexia Nervosa A study of a more specific section of eating disorders has been performed by Veenstra and de Jong (2012.) It found that both the control and the eating disorder patients showed attentional bias against high fat foods and negative eating pictures. The eating disorder patients showed a larger attentional bias against the foods that are considered “bad.” From this study it was hypothesized that a negative attentional bias might facilitate the restricted food intake of the eating disorder patients. Attentional Bias in body dissatisfaction Smeets, Jansen, & Roefs (2005) studied body dissatisfaction and its relation to attentional bias and found that induced bias for unattractive body parts made the participants feel worse about themselves and their body satisfaction decreased, as well as the reverse when a positive bias was induced. Comorbid Disorders Axis I Axis II depression[90] obsessive compulsive personality disorder[91] substance abuse, alcoholism[92] borderline personality disorder[93] anxiety disorders[94] narcissistic personality disorder[95] obsessive compulsive disorder[96][97] histrionic personality disorder[98] Attention-deficit hyperactivity disorder[9][99][100][101] avoidant personality disorder[102] Personality traits__ There are various childhood personality traits associated with the development of eating disorders.[103] 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. 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 viral 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[104] such as the amygdala[105][106] and the prefrontal cortex[107] Disorders in the prefrontal cortex and the executive functioning system have been shown to affect eating behavior.[108][109] Environmental influences__ Child maltreatment__ Child abuse which encompasses physical, psychological and sexual abuse, as well as neglect has been shown by innumerable studies to be a precipitating factor in a wide variety of psychiatric disorders, including eating disorders. Children who are subjected to abuse may develop eating disorders in an effort to gain some sense of control or for a sense of comfort, or they may be in an environment where the diet is unhealthy or insufficient. Child abuse and neglect can cause profound changes in both the physiological structure and the neurochemistry of the developing brain. Children who, as wards of the state, were placed in orphanages or foster homes are especially susceptible to developing a disordered eating pattern. In a study done in New Zealand 25% of the study subjects in foster care exhibited an eating disorder (Tarren-Sweeney M. 2006). An unstable home environment is detrimental to the emotional well-being of children, even in the absence of blatant abuse or neglect the stress of an unstable home can contribute to the development of an eating disorder.[110][111][112][113][114][115][116][117][118] 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.[119][120][121][122] 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.[123] 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.[124][125][126][127][128][129] 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.[130] 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.[131][132][133][134] 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.[citation needed] Cultural pressure__ There is a cultural emphasis on thinness which is especially pervasive in western society. There is an unrealistic stereotype of what constitutes beauty and the ideal body type as portrayed by the media, fashion and entertainment industries. "The cultural pressure on men and women to be 'perfect' is an important predisposing factor for the development of eating disorders".[135][136] 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.[137] 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.[138] 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.[139] However, studies on rates of bulimia 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.[140] Socioeconomic status 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.[141] Some studies have also shown a relationship between increasing body dissatisfaction with increasing socioeconomic status.[142] However, once high SES has been achieved, this relationship weakens and, in some cases, no longer exists.[139] The media plays a major role in the way in which people view themselves. Countless magazine ads and commercials depict rail thin celebrities like Lindsay Lohan, Nicole Richie 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.[143] 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.[144] Pressure from society is also seen within the homosexual community. Homosexual men are at greater risk of eating disorder symptoms than heterosexual men.[145] Within the gay culture, muscularity gives the advantages of both social and sexual desirability and also power.[146] 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.[146] 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.[145][146] 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.[147] 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 has an impact on 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.[148] |
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