Treatment varies according to type and severity of eating disorder, and usually more than one treatment option is utilized. There is no well-established treatment for eating disorders, meaning that current views about treatment are based mainly on clinical experience. 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. Treatment can take place in a variety of different settings such as community programs, hospitals, day programs, and groups. 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.

That said, some treatment methods are:

- Cognitive behavioral therapy (CBT), 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

- Cognitive Remediation Therapy (CRT), a set of cognitive drills or compensatory interventions designed to enhance cognitive functioning.

- Dialectical behavior therapy

- Family therapy including "conjoint family therapy" (CFT), "separated family therapy" (SFT) and Maudsley Family Therapy.

- Behavioral therapy: focuses on gaining control and changing unwanted behaviors.

- Interpersonal psychotherapy (IPT)

- Cognitive Emotional Behaviour Therapy (CEBT)

- Music Therapy

- Recreation Therapy

- Art therapy

- Nutrition counseling and Medical nutrition therapy

- 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.

- Self-help and guided self-help have been shown to be helpful in AN, BN and BED; this includes support groups and self-help groups such as Eating Disorders Anonymous and Overeaters Anonymous.

- Psychoanalysis

- Inpatient care

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

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

Antidepressants of the selective serotonin reuptake inhibitors (SSRI) class may have a modest benefit. This includes fluoxetine, which is FDA approved, for the treatment of bulimia, other antidepressants such as sertraline may also be effective against bulimia. Topiramate may also be useful but has greater side effects.

It is not known if combining medication with counseling improves the outcomes. Any trials which originally suggested that such combinations should improve the outcome have not proven to be exceptionally powerful. Some positive outcomes of treatments can include: abstinence from binge eating, a decrease in obsessive behaviors to lose weight and in shape preoccupation, less severe psychiatric symptoms, a desire to counter the effects of binge eating, as well as an improvement in social functioning and reduced relapse rates.

Three other classes of medications are also used in the treatment of binge eating disorder: antidepressants, anticonvulsants, and anti-obesity medications. Antidepressant medications of the selective serotonin reuptake inhibitor (SSRI) class such as fluoxetine, fluvoxamine, or sertraline have been found to effectively reduce episodes of binge eating and reduce weight. Similarly, anticonvulsant medications such as topiramate and zonisamide may be able to effectively suppress appetite. The long-term effectiveness of medication for binge eating disorder is currently unknown.

Trials of antidepressants, anticonvulsants, and anti-obesity medications suggest that these medications are superior to placebo in reducing binge eating. Medications are not considered the treatment of choice because psychotherapeutic approaches, such as CBT, are more effective than medications for binge eating disorder. Medications also do not increase the effectiveness of psychotherapy, though some patients may benefit from anticonvulsant and anti-obesity medications, such as Phentermine/topiramate, for weight loss.

As of January 2015, lisdexamfetamine was the only drug approved by the Food and Drug Administration in the United States specifically for the treatment of binge eating.

There are several supported psychosocial treatments for bulimia. Cognitive behavioral therapy (CBT), which involves teaching a person to challenge automatic thoughts and engage in behavioral experiments (for example, in session eating of "forbidden foods") has a small amount of evidence supporting its use.

By using CBT people record how much food they eat and periods of vomiting with the purpose of identifying and avoiding emotional fluctuations that bring on episodes of bulimia on a regular basis. Barker (2003) states that research has found 40–60% of people using cognitive behaviour therapy to become symptom free. He states in order for the therapy to work, all parties must work together to discuss, record and develop coping strategies. Barker (2003) claims by making people aware of their actions they will think of alternatives. People undergoing CBT who exhibit early behavioral changes are most likely to achieve the best treatment outcomes in the long run. Researchers have also reported some positive outcomes for interpersonal psychotherapy and dialectical behavior therapy.

Maudsley family therapy, developed at the Maudsley Hospital in London for the treatment of anorexia has been shown promising results in bulimia.

The use of Cognitive Behavioral Therapy (CBT) has been shown to be quite effective for treating bulimia nervosa (BN) in adults, but little research has been done on effective treatments of BN for adolescents. Although CBT is seen as more cost efficient and helps individuals with BN in self-guided care, Family Based Treatment (FBT) might be more helpful to younger adolescents who need more support and guidance from their families. Adolescents are at the stage where their brains are still quite malleable and developing gradually. Therefore, young adolescents with BN are less likely to realize the detrimental consequences of becoming bulimic and have less motivation to change, which is why FBT would be useful to have families intervene and support the teens. Working with BN patients and their families in FBT can empower the families by having them involved in their adolescent's food choices and behaviors, taking more control of the situation in the beginning and gradually letting the adolescent become more autonomous when they have learned healthier eating habits.

With time the symptoms of ARFID can lessen and can eventually disappear without treatment. However, in some cases treatment will be needed as the symptoms persist into adulthood. The most common type of treatment for ARFID is some form of cognitive-behavioral therapy. Working with a clinician can help to change behaviors more quickly than symptoms may typically disappear without treatment. Also hypnotherapy may be used. In that it lessens the anxiety associated with food.

There are support groups for adults with ARFID.

Cognitive behavioral therapy (CBT) treatment has been demonstrated as a more effective form of treatment for BED than behavioral weight loss programs. 50 percent of BED individuals achieve complete remission from binge eating. CBT has also been shown to be an effective method to address self-image issues and psychiatric comorbidities (e.g., depression) associated with the disorder. Recent reviews have concluded that psychological interventions such as psychotherapy and behavioral interventions are more effective than pharmacological interventions for the treatment of binge eating disorder. There is the 12-step Overeaters Anonymous or Food Addicts in Recovery Anonymous.

Children can benefit from a four stage in-home treatment program based on the principles of systematic desensitization. The four stages of the treatment are record, reward, relax and review.

- In the record stage, children are encouraged to keep a log of their typical eating behaviors without attempting to change their habits as well as their cognitive feelings.

- The reward stage involves systematic desensitization. Children create a list of foods that they might like to try eating some day. These foods may not be drastically different from their normal diet, but perhaps a familiar food prepared in a different way. Because the goal is for the children to try new foods, children are rewarded when they sample new foods.

- The relaxation stage is most important for those children that suffer severe anxiety when presented with unfavorable foods. Children learn to relax to reduce the anxiety that they feel. Children work through a list of anxiety-producing stimuli and can create a story line with relaxing imagery and scenarios. Often these stories can also include the introduction of new foods with the help of a real person or fantasy person. Children then listen to this story before eating new foods as a way to imagine themselves participating in an expanded variety of foods while relaxed.

- The final stage, review, is important to keep track of the child's progress. It is important to include both one-on-one sessions with the child, as well as with the parent in order to get a clear picture of how the child is progressing and if the relaxation techniques are working.

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%. 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; acceptance and commitment therapy is a type of CBT, which has shown promise in the treatment of AN. Cognitive remediation therapy (CRT) is used in treating anorexia nervosa.

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.

Few studies guide the treatment of individuals with OSFED. However, cognitive behavioral therapy (CBT), which focuses on the interplay between thoughts, feelings, and behaviors, has been shown to be the leading evidence-based treatment for the eating disorders of BN and BED. For OSFED, a particular cognitive behavioral treatment can be used called CBT-Enhanced (CBT-E), which was designed to treat all forms of eating disorders. This method focuses not only what is thought to be the central cognitive disturbance in eating disorders (i.e., over-evaluation of eating, shape, and weight), but also on modifying the mechanisms that sustain eating disorder psychopathology, such as perfectionism, core low self-esteem, mood intolerance, and interpersonal difficulties. CBT-E showed effectiveness in two studies (total N = 219) and well maintained over 60-week follow-up periods. CBT-E is not specific to individual types of eating disorders but is based on the concept that common mechanisms are involved in the persistence of atypical eating disorders, AN, and BN.

There is no quick cure, and treatment will be based on what problems may be causing the feeding disorder. Depending on the condition, the following steps can be taken: increasing the number of foods that are accepted, increasing the amount of calories and the amount of fluids; checks for vitamin or mineral deficiencies; finding out what the illnesses or psychosocial problems are. To accomplish these goals patients may have to be hospitalized for extensive periods of time. Treatment involves professionals from multiple fields of study including, but not limited to; behavior analysts (Behavioral interventions), occupational and speech therapist who specialize in feeding disorders, dietitians, psychologists and physician. To obtain the best results, treatment should include a behavior modification plan under the guidance of multiple professionals. If the child has oral motor difficulties related to the feeding disorder a pediatric occupational or speech therapist who is trained in feeding disorders and oral motor function should help develop a plan.

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. Such an approach can also make prevention programs to be sustainable.

There are numerous ways in which individuals can reduce emotional distress without engaging in emotional eating. The most salient choice is to minimize maladaptive coping strategies and to maximize adaptive strategies. A study conducted by Corstorphine et al. in 2007 investigated the relationship between distress tolerance and disordered eating. These researchers specifically focused on how different coping strategies impact distress tolerance and disordered eating. They found that individuals who engage in disordered eating often employ emotional avoidance strategies. If an individual is faced with strong negative emotions, they may choose to avoid the situation by distracting themselves through overeating. Discouraging emotional avoidance is thus an important facet to emotional eating treatment. The most obvious way to limit emotional avoidance is to confront the issue through techniques like problem solving. Corstorphine et al. showed that individuals who engaged in problem solving strategies enhance one's ability to tolerate emotional distress. Since emotional distress is correlated to emotional eating, the ability to better manage one's negative affect should allow an individual to cope with a situation without resorting to overeating.

One way to combat emotional eating is to employ mindfulness techniques. For example, approaching cravings with a nonjudgmental inquisitiveness can help differentiate between hunger and emotionally-driven cravings. An individual may ask his or herself if the craving developed rapidly, as emotional eating tends to be triggered spontaneously. An individual may also take the time to note his or her bodily sensations, such as hunger pangs, and coinciding emotions, like guilt or shame, in order to make conscious decisions to avoid emotional eating.

Emotional eating disorder predisposes individuals to more serious eating disorders and physiological complications. Therefore, combatting disordered eating before such progression takes place has become the focus of many clinical psychologists.

Research on treating BDD is limited. Yet anti-depressant medication, such as selective serotonin reuptake inhibitors (SSRIs), and cognitive-behavioral therapy (CBT) are considered effective. SSRIs can help relieve obsessive-compulsive and delusional traits, while cognitive-behavioral therapy can help patients recognize faulty thought patterns. Before treatment, it can help to provide psychoeducation, as with self-help books and support websites.

Treatment of muscle dysmorphia can be stymied by a patient's unawareness that the preoccupation is disordered or by avoidance of treatment. Scientific research on treatment of muscle dysmorphia is limited, the evidence largely in case reports and anecdotes, and no specific protocols have been validated. Still, evidence supports the efficacy of family-based therapy, cognitive behavioural therapy, and pharmacotherapy with selective serotonin reuptake inhibitors. Also limited is research on prognosis of the untreated.

According to the National Eating Disorder Information Centre (NEDIC), the first step for someone going through anorexia athletica is to realize their eating and exercise habits are hurting them. Once an individual has realized they have a disorder, an appointment should be made with the family doctor. A family doctor can advise further medical attention if needed. With sports anorexia, it is important to go to a dietitian as well as a personal trainer. People with sports anorexia need to learn the balance between exercise and caloric intake.

Muscle dysmorphia's classification has been widely debated, and alternative "DSM" classifications have been proposed.

- Eating disorder: Many of muscle dysmorphia's traits overlap with those of eating disorders, including focus on body weight, shape, and modification, whereas body dysmorphic disorder otherwise usually lacks such dietary and exercise components. Also, persons experiencing muscle dysmorphia tend to score high on the Eating Attitudes Test and Eating Disorder Inventory, while muscle dysmorphia and anorexia nervosa share diagnostic crossover. Meanwhile, both muscle dysmorphia and eating disorders associate with higher impairment than does body dysmorphic disorder otherwise. And treatment for eating disorders may be effective for muscle dysmorphia.

- Behavioral addiction: Some researchers seek muscle dysmorphia's reclassification as a behavioral addiction. Muscle dysmorphia's obsession to maintain body image is enacted through particular activities, such as exercise, diet, and related shopping, which activities, as in behavioral addiction, are highly valued, modify mood, and may cause interpersonal conflicts. Also, tolerance to muscle building and dietary restriction can drive escalation of these activities to restore physiological or psychological effects. Further, abstinence from these activities can provoke withdrawal symptoms, and relapse into excessive engagement is apt to occur.

Behavioral addiction and substance abuse disorders are treated similarly; treatment options include exposure and response prevention. No medications have been approved for the treatment of behavioral addictions. Studies have shown promise in the use of glutamatergic altering drugs to treat addictions other than exercise. Exercise addictions comorbid in patients with an eating disorder may be treated through psychotherapy involving education, behavioral interventions, and a strengthened family support structure. In treating the eating disorder, obsessions and compulsions produced by obscured body image ideals will also be treated, this includes exercise addiction.

There are no specific guidelines for the treatment of diabetes and disordered eating, but the standard approach for treatment of two complex conditions as multidisciplinary team of professionals which in this case could include an endocrinologist, psychiatrist, psychologist, dietician, etc.

A number of pharmaceuticals may be used in an attempt to bring the polydipsia under control, including:

- Atypical antipsychotics, such as clozapine, olanzapine and risperidone

- Demeclocycline, a tetracycline antibiotic, which is effective due to the side effect of inducing nephrogenic diabetes insipidus. Demeclocycline is used for cases of psychogenic polydipsia, including those with nocturnal enuresis (bed-wetting). Its mechanism of action involves direct inhibition of vasopressin at the DCTs, thus reducing urine concentration.

There are a number of emerging pharmaceutical treatments for psychogenic polydipsia, although these need further investigation:

- ACE Inhibitors, such as enalapril

- Clonidine, an alpha-2 adrenergic agonist

- Irbesartan, an angiotensin II receptor antagonist

- Propranolol, a sympatholytic beta blocker

- Vasopressin receptor antagonists, such as conivaptan

- Acetazolamide, a carbonic anhydrase inhibitor

Lithium was previously used for treatment of PPD as a direct competitive ADH agonist, but is now generally avoided due to its toxic effects on the thyroid and kidneys.

It is important to note that the majority of psychotropic drugs (and a good many of other classes) can cause dry mouth as a side effect, but this is not to be confused with true polydipsia in which a dangerous drop in serum sodium will be seen.

Some of the differential or comorbid medical diagnoses may include:

- achalasia – There have been cases where achalasia, a disorder of the esophagus which affects peristalsis, has been misdiagnosed as AN. It has been reported in cases where there is sub-clinical manifestation of anorexia nervosa and also in cases where the full diagnostic criteria AN have been met.

- acute pandysautonomia is one form of an autonomic neuropathy, which is a collection of various syndromes and diseases which affect the autonomic neurons of the autonomic nervous system (ANS). Autonomic neuropathies may be the result of an inherited condition or they may be acquired due to various premorbid conditions such as diabetes and alcoholism, bacterial infection such as Lyme disease or a viral illness. Some of the symptoms of ANS which may be associated with an ED include nausea, dysphagia, constipation, pain in the salivary glands, early saiety. It also affects peristalsis in the stomach. Acute pandysautonomia may cause emotional instability and has been misdiagnosed as various psychiatric disorders including hysterical neurosis and anorexia nervosa.

- Lupus: various neuropsychiatric symptoms are associated with systemic lupus erythematosus (SLE), including depression. Anorexia and weight loss also may occur with SLE and while rare it may be misdiagnosed as AN.

- Lyme disease is known as the "great imitator", as it may present as a variety of psychiatric or neurologic disorders including anorexia nervosa. "A 12 year old boy with confirmed Lyme arthritis treated with oral antibiotics subsequently became depressed and anorectic. After being admitted to a psychiatric hospital with the diagnosis of anorexia nervosa, he was noted to have positive serologic tests for Borrelia burgdorferi. Treatment with a 14 day course of intravenous antibiotics led to a resolution of his depression and anorexia; this improvement was sustained on 3 year follow-up." Serologic testing can be helpful but should not be the sole basis for diagnosis. The Centers for Disease Control (CDC) issued a cautionary statement (MMWR 54;125) regarding the use of several commercial tests. Clinical diagnostic criteria have been issued by the CDC (CDC, MMWR 1997; 46: 531-535).

- Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare genetic disorder characterized by gastrointestinal dysmotility, severe cachexia progressive external ophthalmoplegia, post-prandial emesis (vomiting after eating), peripheral neuropathy, and diffuse leukoencephalopathy. Onset is prior to age 20 in 60% of cases. ""Miss A" was a 21-year-old Indian woman diagnosed as having treatment-resistant anorexia nervosa." It was subsequently proven to be MNGIE

- superior mesenteric artery syndrome (SMA syndrome) "is a gastrointestinal disorder characterized by the compression of the third or transverse portion of the duodenum against the aorta by the superior mesenteric artery resulting in chronic partial, incomplete, acute or intermittent duodenal obstruction". It may occur as a complication of AN or as a differential diagnosis. There have been reported cases of a tentative diagnosis of AN, where upon treatment for SMA syndrome the patient is asymptomatic.

- 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.

- Brain tumors: There are multiple cases were the neuropsychiatric symptoms of a brain tumor were attributed to AN, resulting in misdiagnosis. The tumors in these cases were noted in various regions of the brain including the medulla oblongata, hypothalamus, pituitary gland, pineal gland and the obex.

- Simmond's disease (organic hypopituitarism) – "A 20-year-old Japanese man with a hypothalamic tumor which caused hypopituitarism and diabetes insipidus was mistakenly diagnosed as anorexia nervosa because of anorexia, weight loss, denial of being ill, changes in personality, and abnormal behavior resembling the clinical characteristics of anorexia nervosa"

- Brain calcification either dystrophic calcification or metastatic calcification can present with neuropsychiatric symptoms including those associated with AN and comorbid disorders such as obsessive compulsive disorder.

- cysts that occur in the central nervous system such as dermoid cysts and arachnoid cysts can cause neuropsychiatric symptoms including psychosis.

- Celiac disease is an inflammatory disorder triggered by peptides from wheat and similar grains which cause an immune reaction in the small intestine. "information on the role of the gastrointestinal system in causing or mimicking eating disorders is scarce."(Leffler DA "et al.")

- Gall bladder disease which may be caused by inflammation, infection, gallstones, obstruction of the gallbladder or torsion of the gall bladder – Many of the symptoms of gall bladder disease may mimic anorexia nervosa (AN). Laura Daly, a woman from Missouri, suffered from an inherited disorder in which the gall bladder was not properly attached; the resultant complications led to multiple erroneous diagnoses of AN. Upon performance of a CCK test, standard imaging techniques are done with the patient lying prone, in this instance it was done with the patient in an upright position. The gall bladder was shown to be in an abnormal position having flipped over the liver. The gallbladder was removed and the patient has since recovered. The treatment was performed by William P. Smedley in Pennsylvania.

- colonic tuberculosis misdiagnosed as anorexia nervosa in a physician at the hospital where she worked – "This patient, who had severe wasting, was misdiagnosed as having anorexia nervosa despite the presence of other symptoms suggestive of an organic disease, namely, fever and diarrhea"(Madani, A 2002).

- Crohn's disease: "We report three cases of young 18 to 25 year-old girls, initially treated for anorexia nervosa in a psychiatric department. Diagnosis of Crohn's disease was made within 5 to 13 years."(Blanchet C, Luton JP. 2002)"This disease should be diagnostically excluded before accepting anorexia nervosa as final diagnosis". (Wellmann W "et al.")

- hypothyroidism, hyperthyroidism, hypoparathyroidism and hyperparathyroidism may mimic some of the symptoms of, can occur concurrently with, be masked by or exacerbate an eating disorder and/or various comorbid disorders such as anxiety and depression.

- Insulinomas are (pancreatic tumors) that cause an overproduction of insulin, causing hypoglycemia. Various neurological deficits have been ascribed to this condition including misdiagnosis as an eating disorder.

- Multiple sclerosis (encephalomyelitis disseminata) is a progressive autoimmune disorder in which the protective covering (myelin sheath) of nerve cells is damaged as a result of inflammation and resultant attack by the bodies own immune system. In its initial presentation, MS has been misdiagnosed as an eating disorder.

Emotional eating may qualify as avoidant coping and/or emotion-focused coping. As coping methods that fall under these broad categories focus on temporary reprieve rather than practical resolution of stressors, they can initiate a vicious cycle of maladaptive behavior reinforced by fleeting relief from stress. Additionally, in the presence of high insulin levels characteristic of the recovery phase of the stress-response, glucocorticoids trigger the creation of an enzyme that stores away the nutrients circulating in the bloodstream after an episode of emotional eating as visceral fat, or fat located in the abdominal area. Therefore, those who struggle with emotional eating are at greater risk for abdominal obesity, which is in turn linked to a greater risk for metabolic and cardiovascular disease.

Behavioural treatments may involve the use of a token economy to provide positive reinforcement to desirable behaviour. Furthermore, cognitive therapy techniques can be used to address the thought patterns that lead to compulsive drinking behaviour. Success has been seen in trials of this technique, with emphasis on the development of coping techniques (e.g. taking small sips of water, having ice cubes instead of drinks) in addition to challenging delusions leading to excessive drinking.

Psychogenic polydipsia often leads to institutionalisation of mentally ill patients, since it is difficult to manage in the community. Most studies of behavioural treatments occur in institutional settings and require close monitoring of the patient and a large degree of time commitment from staff.

The differential diagnoses of anorexia nervosa (AN) includes various types of medical and psychological conditions, which may be misdiagnosed as AN. In some cases, these conditions may be comorbid with AN because the misdiagnosis of AN is not uncommon. For example, a case of achalasia was misdiagnosed as AN and the patient spent two months confined to a psychiatric hospital. A reason for the differential diagnoses that surround AN arise mainly because, like other disorders, it is primarily, albeit defensively and adaptive for, the individual concerned.

Anorexia Nervosa is a psychological disorder characterized by extremely reduced intake of food. People suffering from Aneroxia Nervosa have a low self-image and consider themselves overweight.

Common behaviors and signs of someone suffering from AN:

- Forcing oneself to vigorously exercise even in adverse conditions or when their health does not permit it.

- Forcing own self to urinate and excrete waste product from the body.

- Using substituted amphetamines (stimulants that can reduce appetite) to reduce appetite.

- Skin turning yellow

The five OSFED examples that can be considered eating disorders include atypical AN, BN (of low frequency and/or limited duration), BED (of low frequency and/or limited duration), purging disorder, and NES. Of note, OSFED is not limited to these five examples, and can include individuals with heterogeneous eating disorder presentations (i.e., OSFED-other). Another term, Unspecified Feeding or Eating Disorder (UFED), is used to describe individuals for whom full diagnostic criteria are not met but the reason remains unspecified or the clinician does not have adequate information to make a more definitive diagnosis.

- Atypical Anorexia Nervosa: In atypical AN, individuals meet all of the criteria for AN, with the exception of the weight criterion: the individual's weight remains within or above the normal range, despite significant weight loss.

- Atypical Bulimia Nervosa: In this sub-threshold version of BN, individuals meet all criteria for BN, with the exception of the frequency criterion: binge eating and inappropriate compensatory behaviors occur, on average, less than once a week and/or for fewer than 3 months.

- Binge-eating disorder (of low frequency and/or limited duration): In this sub-threshold version of BED, individuals must meet all criteria for BED, with the exception of the frequency criterion: binge eating occurs, on average, less than once a week and/or for fewer than 3 months.

- Purging Disorder: In purging disorder, purging behavior aimed to influence weight or shape is present, but in the absence of binge eating.

- Night Eating Syndrome: In NES, individuals have recurrent episodes of eating at night, such as eating after awakening from sleep or excess calorie intake after the evening meal. This eating behavior is not culturally acceptable by group norms, such as the occasional late-night munchies after a gathering. NES includes an awareness and recall of the eating, is not better explained by external influences such as changes in the individual's sleep-wake cycle, and causes significant distress and/or impairment of functioning. Though not defined specifically in "DSM-5", research criteria for this diagnosis proposed adding the following criteria (1) the consumption of at least 25% of daily caloric intake after the evening meal and/or (2) evening awakenings with ingestions at least twice per week.