the person's current mood and thought content, focusing on views on weight and patterns of eating. dsm-5 anorexia nervosa is classified under the feeding and eating disorders in the latest revision of the diagnostic and statistical manual of mental disorders (dsm 5). there is no specific bmi cut-off that defines low weight required for the diagnosis of anorexia nervosa. the diagnostic criteria for anorexia nervosa (all of which needing to be met for diagnosis) are: restriction of energy intake relative to requirements leading to a low body weight. (criterion a) intense fear of gaining weight or persistent behaviors that interfere with gaining weight. (criterion b) disturbance in the way a person's weight or body shape is experienced or a lack of recognition about the risks of the low body weight. (criterion c) relative to the previous version of the dsm (dsm-iv-tr), the 2013 revision (dsm5) reflects changes in the criteria for anorexia nervosa. most notably, the amenorrhea (absent period) criterion was removed. amenorrhea was removed for several reasons: it does not apply to males, it is not applicable for females before or after the age of menstruation or taking birth control pills, and some women who meet the other criteria for an still report some menstrual activity. subtypes there are two subtypes of an: binge-eating/purging type: patients with anorexia could show binge eating and purging behavior. it is different from bulimia nervosa in terms of the individual's weight. an individual with binge-eating/purging type anorexia is usually significantly underweight. people with bulimia nervosa on the other hand can sometimes be normal-weight or overweight. restricting type: the individual uses restricting food intake, fasting, diet pills, or exercise as a means for losing weight; they may exercise excessively to keep off weight or prevent weight gain, and some individuals eat only enough to stay alive. in the restrictive type, there are no recurrent episodes of binge-eating or purging present. levels of severity body mass index (bmi) is used by the dsm-5 as an indicator of the level of severity of anorexia nervosa. the dsm-5 states these as follows: mild: bmi of greater than 17 moderate: bmi of 16–16.99 severe: bmi of 15–15.99 extreme: bmi of less than 15 investigations medical tests to check for signs of physical deterioration in anorexia nervosa may be performed by a general physician or psychiatrist, including: complete blood count (cbc): a test of the white blood cells, red blood cells and platelets used to assess the presence of various disorders such as leukocytosis, leukopenia, thrombocytosis and anemia which may result from malnutrition. urinalysis: a variety of tests performed on the urine used in the diagnosis of medical disorders, to test for substance abuse, and as an indicator of overall health chem-20: chem-20 also known as sma-20 a group of twenty separate chemical tests performed on blood serum. tests include protein and electrolytes such as potassium, chlorine and sodium and tests specific to liver and kidney function. glucose tolerance test: oral glucose tolerance test (ogtt) used to assess the body's ability to metabolize glucose. can be useful in detecting various disorders such as diabetes, an insulinoma, cushing's syndrome, hypoglycemia and polycystic ovary syndrome. lipid profile: includes cholesterol (including total cholesterol, hdl and ldl) and triglycerides. serum cholinesterase test: a test of liver enzymes (acetylcholinesterase and pseudocholinesterase) useful as a test of liver function and to assess the effects of malnutrition. liver function test: a series of tests used to assess liver function some of the tests are also used in the assessment of malnutrition, protein deficiency, kidney function, bleeding disorders, and crohn's disease. luteinizing hormone (lh) response to gonadotropin-releasing hormone (gnrh): tests the pituitary glands' response to gnrh, a hormone produced in the hypothalamus. hypogonadism is often seen in anorexia nervosa cases. creatine kinase (ck) test: measures the circulating blood levels of creatine kinase an enzyme found in the heart (ck-mb), brain (ck-bb) and skeletal muscle (ck-mm). blood urea nitrogen (bun) test: urea nitrogen is the byproduct of protein metabolism first formed in the liver then removed from the body by the kidneys. the bun test is primarily used to test kidney function. a low bun level may indicate the effects of malnutrition. bun-to-creatinine ratio: a bun to creatinine ratio is used to predict various conditions. a high bun/creatinine ratio can occur in severe hydration, acute kidney failure, congestive heart failure, and intestinal bleeding. a low bun/creatinine ratio can indicate a low protein diet, celiac disease, rhabdomyolysis, or cirrhosis of the liver. electrocardiogram (ekg or ecg): measures electrical activity of the heart. it can be used to detect various disorders such as hyperkalemia. electroencephalogram (eeg): measures the electrical activity of the brain. it can be used to detect abnormalities such as those associated with pituitary tumors. thyroid function tests: tests used to assess thyroid functioning by checking levels of thyroid-stimulating hormone (tsh), thyroxine (t4), and triiodothyronine (t3). differential diagnoses main article: differential diagnoses of anorexia nervosa a variety of medical and psychological conditions have been misdiagnosed as anorexia nervosa; in some cases the correct diagnosis was not made for more than ten years. the distinction between binge purging anorexia, bulimia nervosa and other specified feeding or eating disorders (osfed) is often difficult for non-specialist clinicians. a main factor differentiating binge-purge anorexia from bulimia is the gap in physical weight. patients with bulimia nervosa are ordinarily at a healthy weight, or slightly overweight. patients with binge-purge anorexia are commonly underweight. moreover, patients with the binge-purging subtype may be significantly underweight and typically do not binge-eat large amounts of food. in contrast, those with bulimia nervosa tend to binge large amounts of food. it is not unusual for patients with an eating disorder to "move through" various diagnoses as their behavior and beliefs change over time. treatment there is no conclusive evidence that any particular treatment for anorexia nervosa works better than others. treatment for anorexia nervosa tries to address three main areas. restoring the person to a healthy weight; treating the psychological disorders related to the illness; reducing or eliminating behaviors or thoughts that originally led to the disordered eating. in some clinical settings a specific body image intervention is performed to reduce body dissatisfaction and body image disturbance. although restoring the person's weight is the primary task at hand, optimal treatment also includes and monitors behavioral change in the individual as well. there is some evidence that hospitalization might adversely affect long term outcome, but sometimes is necessary. psychotherapy for individuals with an is challenging as they may value being thin and may seek to maintain control and resist change. initially, developing a desire to change is fundamental. despite no evidence for better treatment in adults patients, research stated that family based therapy is the primary choice for adolescents with an. therapy family-based treatment (fbt) has been shown to be more successful than individual therapy for adolescents with an. various forms of family-based treatment have been proven to work in the treatment of adolescent an including conjoint family therapy (cft), in which the parents and child are seen together by the same therapist, and separated family therapy (sft) in which the parents and child attend therapy separately with different therapists. proponents of family therapy for adolescents with an assert that it is important to include parents in the adolescent's treatment. a four- to five-year follow up study of the maudsley family therapy, an evidence-based manualized model, showed full recovery at rates up to 90%. the maudsley model of family therapy is problem focused, and the treatment targets re-establishing regular eating, weight restoration, and the reduction of illness behaviors like purging. the maudsley model is split into three phases, with phase on focusing on the parents implementing weight restoration in the child; phase two transitioning control over food back to the individual at an age-appropriate level; and phase three focusing on other issues related to typical adolescent development (e.g., social and other psychological developments), and helps parents learn how to interact with their child. although this model is recommended by the nimh, critics claim that it has the potential to create power struggles in an intimate relationship and may disrupt equal partnerships. cognitive behavioral therapy (cbt) is useful in adolescents and adults with anorexia nervosa. one of the most known psychotherapy in the field is cbt-e, an enhanced cognitive-behavior therapy specifically focus to eating disorder psychopathology. acceptance and commitment therapy is a third-wave cognitive-behavioral therapy which has shown promise in the treatment of an. cognitive remediation therapy (crt) is also used in treating anorexia nervosa. schema-focused therapy (a form of cbt) was developed by dr. jeffrey young and is effective in helping patients identify origins and triggers for disordered eating. diet diet is the most essential factor to work on in people with anorexia nervosa, and must be tailored to each person's needs. food variety is important when establishing meal plans as well as foods that are higher in energy density. people must consume adequate calories, starting slowly, and increasing at a measured pace. evidence of a role for zinc supplementation during refeeding is unclear. medication pharmaceuticals have limited benefit for anorexia itself. there is a lack of good information from which to make recommendations concerning the effectiveness of antidepressants in treating anorexia. administration of olanzapine has been shown to result in a modest but statistically significant increase in body weight of anorexia nervosa patients. admission to hospital patients with an may be deemed to have a lack of insight regarding the necessity of treatment, and thus may be involuntarily treated without their consent.: 1038 an has a high mortality and patients admitted in a severely ill state to medical units are at particularly high risk. diagnosis can be challenging, risk assessment may not be performed accurately, consent and the need for compulsion may not be assessed appropriately, refeeding syndrome may be missed or poorly treated and the behavioural and family problems in an may be missed or poorly managed. guidelines published by the royal college of psychiatrists recommend that medical and psychiatric experts work together in managing severely ill people with an. refeeding syndrome the rate of refeeding can be difficult to establish, because the fear of refeeding syndrome (rfs) can lead to underfeeding. it is thought that rfs, with falling phosphate and potassium levels, is more likely to occur when bmi is very low, and when medical comorbidities such as infection or cardiac failure, are present. in those circumstances, it is recommended to start refeeding slowly but to build up rapidly as long as rfs does not occur. recommendations on energy requirements vary, from 5–10 kcal/kg/day in the most medically compromised patients, who appear to have the highest risk of rfs, to 1900 kcal/day. experience of treatment patients involved in treatment sometimes felt that treatment focused on biological aspects of body weight and eating behaviour change rather than their perceptions or emotional state.: 8 patients felt that a therapists trust in them shown by being treated as a complete person with their own capacities was significant.: 9 some patients defined recovery from an in terms of reclaiming a lost identity.: 10 healthcare workers involved in the treatment of anorexia reported frustration and anger to set backs in treatment and noncompliance and were afraid of patients dying. some healthcare workers felt that they did not understand the treatment and that medical doctors were making decisions.: 11 they may feel powerless to improve a patient's situation and deskilled as a result.: 12 healthcare workers involved in monitoring patients consumption of food felt watched themselves.: 12 healthcare workers often feel a degree of moral dissonance of not being in control of outcomes which they may protect against by focusing on individual tasks, avoiding identifying with patients (for example by making their eating behavior very different and not sharing personal information with patients), and blaming patients for their distress.: 13,14 healthcare workers would inflexibly follow process to avoid responsibility.: 13 healthcare workers attempted to reach balance by gradually giving patients back control avoiding feeling sole responsibility for outcomes, being mindful of their emotional state, and trying to view eating disorders as external from patients.: 13 prognosis deaths due to eating disorders per million persons in 2012 0–1 1–2 2–3 3–4 4–25 an has the highest mortality rate of any psychological disorder. the mortality rate is 11 to 12 times greater