binge eating-purging type or those with purging-type bulimia nervosa, are at risk for acid reflux. 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. other possible manifestations are dry lips, burning tongue, parotid gland swelling, and temporomandibular disorders. 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. the main psychopathological features of anorexia were outlined in 1982 as problems in body perception, emotion processing and interpersonal relationships. women with eating disorders have greater body dissatisfaction. this impairment of body perception involves vision, proprioception, interoception and tactile perception. there is an alteration in integration of signals in which body parts are experienced as dissociated from the body as a whole. bruch once theorized that difficult early relationships were related to the cause of anorexia and how primary caregivers can contribute to the onset of the illness. a prominent feature of bulimia is dissatisfaction with body shape. however, dissatisfaction with body shape is not of diagnostic significance as it is sometimes present in individuals with no eating disorder. this highly labile feature can fluctuate depending on changes in shape and weight, the degree of control over eating and mood. in contrast, a necessary diagnostic feature for anorexia nervosa and bulimia nervosa is having overvalued ideas about shape and weight are relatively stable and partially related to the patients' low self-esteem. 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. 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. 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. causes the causes of eating disorders are not yet clearly established. many people with eating disorders also have body image disturbance and a comorbid body dysmorphic disorder, leading them to an altered perception of their body. 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. 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. there are also many other possibilities such as environmental, social and interpersonal issues that could promote and sustain these illnesses. 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. genetics numerous studies show a genetic predisposition toward eating disorders. 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. a genetic link has been found on chromosome 1 in multiple family members of an individual with anorexia nervosa. 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. 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. about 50% of eating disorder cases are attributable to genetics. other cases are due to external reasons or developmental problems. there are also other neurobiological factors at play tied to emotional reactivity and impulsivity that could lead to binging and purging behaviors. 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. other candidate genes for epigenetic studies in eating disorders include leptin, pro-opiomelanocortin (pomc) and brain-derived neurotrophic factor (bdnf). there has found to be a genetic correlation between anorexia nervosa and ocd, suggesting a strong etiology. first and second relatives of probands with ocd have a greater chance of developing anorexia nervosa as genetic relatedness increases. psychological eating disorders are classified as axis i 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. some people have a previous disorder which may increase their vulnerability to developing an eating disorder. some develop them afterwards. the severity and type of eating disorder symptoms have been shown to affect comorbidity. there has been controversy over various editions of the dsm diagnostic criteria including the latest edition, dsm-v, due in may 2013. comorbid disorders axis iaxis ii depressionobsessive–compulsive personality disorder substance abuse, alcoholismborderline personality disorder anxiety disordersnarcissistic personality disorder obsessive–compulsive disorderhistrionic personality disorder attention-deficit hyperactivity disorderavoidant personality disorder cognitive attentional bias attentional bias may have an effect on eating disorders. attentional bias is the preferential attention toward certain types of information in the environment while simultaneously ignoring others. individuals with eating disorders can be thought to have schemas, knowledge structures, which are dysfunctional as they may bias judgement, thought, behaviour in a manner that is self-destructive or maladaptive. they may have developed a disordered schema which focuses on body size and eating. thus, this information is given the highest level of importance and overvalued among other cognitive structures. researchers have found that people who have eating disorders tend to pay more attention to stimuli related to food. for people struggling to recover from an eating disorder or addiction, this tendency to pay attention to certain signals while discounting others can make recovery that much more difficult. studies have utilized the stroop task to assess the probable effect of attentional bias on eating disorders. this may involve separating food and eating words from body shape and weight words. such studies have found that anorexic subjects were slower to colour name food related words than control subjects. other studies have noted that individuals with eating disorders have significant attentional biases associated with eating and weight stimuli. personality traits there are various childhood personality traits associated with the development of eating disorders, such as perfectionism and neuroticism. these personality traits are found to link eating disorders and ocd. 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. 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 such as the amygdala and the prefrontal cortex. disorders in the prefrontal cortex and the executive functioning system have been shown to affect eating behavior. celiac disease people with gastrointestinal disorders may be more risk of developing disordered eating practices than the general population, principally restrictive eating disturbances. an association of anorexia nervosa with celiac disease has been found. 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. 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, specially in women. 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. sexual abuse appears to be about double the risk of bulimia; however, the association is less clear for anorexia. the risk for individuals developing eating disorders increases if the individual grew up in an invalidating environment where displays of emotions were often punished. abuse that has also occurred in childhood produces intolerable difficult emotions that cannot be expressed in a healthy manner. eating disorders come in as an escape coping mechanism, as a means to control and avoid overwhelming negative emotions and feelings. those who report physical or sexual maltreatment as a child are at an increased risk of developing an eating disorder. 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. waller, kennerley and ohanian (2007) argued that both bingeing–vomiting and restriction are emotion suppression strategies, but they are