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

These eating disorders are specified as mental disorders in standard medical manuals, such as in the ICD-10, 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. 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. 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. 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. 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 and guilt after overeating. The disorder can develop within individuals of a wide range of ages and socioeconomic classes.

- 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.

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.

Symptoms and complications vary according to the nature and severity of the eating disorder:

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. 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. 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.

Bulimia typically involves rapid and out-of-control eating, which may stop when the bulimic is interrupted by another person or the stomach hurts from over-extension, followed by self-induced vomiting or other forms of purging. This cycle may be repeated several times a week or, in more serious cases, several times a day and may directly cause:

- Chronic gastric reflux after eating, secondary to vomiting

- Dehydration and hypokalemia due to renal potassium loss in the presence of alkalosis and frequent vomiting

- Electrolyte imbalance, which can lead to abnormal heart rhythms, cardiac arrest, and even death

- Esophagitis, or inflammation of the esophagus

- Mallory-Weiss tears

- Boerhaave syndrome, a rupture in the esophageal wall due to vomiting

- Oral trauma, in which repetitive insertion of fingers or other objects causes lacerations to the lining of the mouth or throat

- Russell's sign: calluses on knuckles and back of hands due to repeated trauma from incisors

- Perimolysis, or severe dental erosion of tooth enamel

- Swollen salivary glands (for example, in the neck, under the jaw line)

- Gastroparesis or delayed emptying

- Constipation

- Peptic ulcers

- Infertility

- Constant weight fluctuations are common

These are some of the many signs that may indicate whether someone has bulimia nervosa:

- A fixation on the number of calories consumed

- A fixation on and extreme consciousness of ones weight

- Low self-esteem and/or self harming

- Suicidal tendencies

- Low blood pressure

- An irregular menstrual cycle in woman

- Regular trips to the bathroom, especially soon after eating

- Depression, anxiety disorders and sleep disorders

- Frequent occurrences involving consumption of abnormally large portions of food

- The use of laxatives and diet pills

- Unhealthy/dry skin, hair, nails and lips

- A lack of energy

As with many psychiatric illnesses, delusions can occur, in conjunction with other signs and symptoms, leaving the person with a false belief that is not ordinarily accepted by others.

People with bulimia nervosa may also exercise to a point that excludes other activities.

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.

Anorexia nervosa is an eating disorder characterized by attempts to lose weight, to the point of starvation. A person with anorexia nervosa may exhibit a number of signs and symptoms, the type and severity of which may vary and may be present but not readily apparent.

Anorexia nervosa, and the associated malnutrition that results from self-imposed starvation, can cause complications in every major organ system in the body. Hypokalaemia, a drop in the level of potassium in the blood, is a sign of anorexia nervosa. A significant drop in potassium can cause abnormal heart rhythms, constipation, fatigue, muscle damage and paralysis.

Symptoms may include:

- A low body mass index for one's age and height.

- Amenorrhea, a symptom that occurs after prolonged weight loss; causes menses to stop, hair becomes brittle, and skin becomes yellow and unhealthy.

- Fear of even the slightest weight gain; taking all precautionary measures to avoid weight gain or becoming "overweight".

- Rapid, continuous weight loss.

- Lanugo: soft, fine hair growing over the face and body.

- An obsession with counting calories and monitoring fat contents of food.

- Preoccupation with food, recipes, or cooking; may cook elaborate dinners for others, but not eat the food themselves or consume a very small portion.

- Food restrictions despite being underweight or at a healthy weight.

- Food rituals, such as cutting food into tiny pieces, refusing to eat around others and hiding or discarding of food.

- Purging: May use laxatives, diet pills, ipecac syrup, or water pills to flush food out of their system after eating or may engage in self-induced vomiting though this is a more common symptom of bulimia.

- Excessive exercise including micro-exercising, for example making small persistent movements of fingers or toes.

- Perception of self as overweight, in contradiction to an underweight reality.

- Intolerance to cold and frequent complaints of being cold; body temperature may lower (hypothermia) in an effort to conserve energy due to malnutrition.

- Hypotension or orthostatic hypotension.

- Bradycardia or tachycardia.

- Depression, anxiety disorders and insomnia.

- Solitude: may avoid friends and family and become more withdrawn and secretive.

- Abdominal distension.

- Halitosis (from vomiting or starvation-induced ketosis).

- Dry hair and skin, as well as hair thinning.

- Chronic fatigue.

- Rapid mood swings.

- Having feet discoloration causing an orange appearance.

- Having severe muscle tension + aches and pains.

- Evidence/habits of self harming or self-loathing.

- Admiration of thinner people.

Someone with anorexia athletica can experience numerous signs and symptoms, a few of which are listed below. The seriousness of the symptoms is dependent on the individual, and more symptoms come with the length the athlete excessively exercises. If anorexia athletica persists for long enough, the individual can become malnourished, which eventually leads to further complications in major organs such as the liver, kidney, heart and brain.

- Excessive exercise

- Obsessive behavior with calories, fat, and weight

- Self-worth is based on physical performance

- Enjoyment of sports is diminished or gone

- Denying the over exercising is a problem

The fifth edition of the "Diagnostic and Statistical Manual of Mental Disorders" (DSM-5) renamed "Feeding Disorder of Infancy or Early Childhood" to Avoidant/Restrictive Food Intake Disorder, and broadened the diagnostic criteria. Previously defined as a disorder exclusive to children and adolescents, the DSM-5 broadened the disorder to include adults who limit their eating and are affected by related physiological or psychological problems, but who do not fall under the definition of another eating disorder.

The DSM-5 defines the following diagnostic criteria:

- Disturbance in eating or feeding, as evidenced by one or more of:

- Substantial weight loss (or, in children, absence of expected weight gain)

- Nutritional deficiency

- Dependence on a feeding tube or dietary supplements

- Significant psychosocial interference

- Disturbance not due to unavailability of food, or to observation of cultural norms

- Disturbance not due to anorexia nervosa or bulimia nervosa, and no evidence of disturbance in experience of body shape or weight

- Disturbance not better explained by another medical condition or mental disorder, or when occurring concurrently with another condition, the disturbance exceeds what is normally caused by that condition

In previous years, the DSM was not inclusive in recognizing all of the challenges associated with feeding and eating disorders in 3 main domains:

- Eating Disorders Not Otherwise Specified (EDNOS) was an all-inclusive, placeholder group for all individuals that presented challenges with feeding

- The category of Feeding Disorder of Infancy/ Early Childhood was noted to be too broad, limiting specification when treating these behaviors

- There are children and youth who present feeding challenges but do not fit within any existing categories to date

Children are often picky eaters, this does not necessarily mean they meet the criteria for an ARFID diagnosis. In addition, self-identification as having ARFID may contribute to ARFID.

Other psychological issues may factor into anorexia nervosa; 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. Some people have a previous disorder which may increase their vulnerability to developing an eating disorder and some develop them afterwards. The presence of Axis I or Axis II psychiatric comorbidity has been shown to affect the severity and type of anorexia nervosa symptoms in both adolescents and adults.

Obsessive-compulsive disorder (OCD) and obsessive-compulsive personality disorder (OCPD) are highly comorbid with AN, particularly the restrictive subtype. Obsessive-compulsive personality disorder is linked with more severe symptomatology and worse prognosis. The causality between personality disorders and eating disorders has yet to be fully established. Other comorbid conditions include depression, alcoholism, borderline and other personality disorders, anxiety disorders, attention deficit hyperactivity disorder, and body dysmorphic disorder (BDD). Depression and anxiety are the most common comorbidities, and depression is associated with a worse outcome.

Autism spectrum disorders occur more commonly among people with eating disorders than in the general population. Zucker "et al." (2007) proposed that conditions on the autism spectrum make up the cognitive endophenotype underlying anorexia nervosa and appealed for increased interdisciplinary collaboration.

Other specified feeding or eating disorder or OSFED is the "DSM-5" category that replaces the category formerly called Eating Disorder Not Otherwise Specified (EDNOS) in "DSM-IV", and that captures feeding disorders and eating disorders of clinical severity that do not meet diagnostic criteria for anorexia nervosa (AN), bulimia nervosa (BN), binge eating disorder (BED), avoidant/restrictive food intake disorder (ARFID), pica, or rumination disorder. OSFED includes five examples: atypical AN, BN (of low frequency and/or limited duration), BED (of low frequency and/or limited duration), purging disorder, and night eating syndrome (NES).

Sufferers of ARFID have an inability to eat certain foods. "Safe" foods may be limited to certain food types and even specific brands. In some cases, afflicted individuals will exclude whole food groups, such as fruits or vegetables. Sometimes excluded foods can be refused based on color. Some may only like very hot or very cold foods, very crunchy or hard-to-chew foods, or very soft foods, or avoid sauces.

Most sufferers of ARFID will still maintain a healthy or normal body weight. There are no specific outward appearances associated with ARFID. Sufferers can experience physical gastrointestinal reactions to adverse foods such as retching, vomiting or gagging. Some studies have identified symptoms of social avoidance due to their eating habits. Most, however, would change their eating habits if they could.

With regards to interoception, people with bulimia report reduced sensitivity to many kinds of internal and external sensations. For example, some show increased thresholds to heat pain compared and report the same level of satiety after consuming more calories than do healthy subjects.

Binge eating is the core symptom of BED; however, not everyone who binge eats has BED. An individual may occasionally binge eat without experiencing many of the negative physical, psychological, or social effects of BED. This example may be considered an eating problem (or not), rather than a disorder. Precisely defining binge eating can be problematic, however binge eating episodes in BED are generally described as having the following potential features:

- Eating much faster than normal during a binge perhaps in a short space of time

- Eating until feeling uncomfortably full

- Eating a large amount when not hungry

- Subjective loss of control over how much or what is eaten

- Binges may be planned in advance, involving the purchase of special binge foods, and the allocation of specific time for binging, sometimes at night

- Eating alone or secretly due to embarrassment over the amount of food consumed

- There may be a dazed mental state during the binge

- Not being able to remember what was eaten after the binge

- Feelings of guilt, shame or disgust following a food binge

In contrast to bulimia nervosa, binge eating episodes are not regularly followed by activities intended to prevent weight gain, such as self-induced vomiting, laxative or enema misuse, or strenuous exercise. BED is characterized more by overeating than dietary restriction and over concern about body shape. Obesity is common in persons with BED, as are depressive features, low self-esteem, stress and boredom.

The three general categories for an EDNOS diagnosis are subthreshold symptoms of anorexia or bulimia, a mixture of both anorexia or bulimia, and eating behaviors that are not particularized by anorexia and bulimia. EDNOS is no longer considered a diagnosis in "DSM-5"; those displaying symptoms of what would previously have been considered EDNOS are now classified under Other Specified Feeding or Eating Disorder.

Binge eating disorder (BED) is an eating disorder characterized by frequent and recurrent binge eating episodes with associated negative psychological and social problems, but without subsequent purging episodes (e.g. vomiting).

BED is a recently described condition, which was required to distinguish binge eating similar to that seen bulimia nervosa but without characteristic purging. Individuals who are diagnosed with bulimia nervosa and binge eating disorder exhibit similar patterns of compulsive overeating, neurobiological features of dysfunctional cognitive control and food addiction, and biological and environmental risk factors. Indeed, some consider BED a milder version of bulimia nervosa, and that the conditions are on the same spectrum.

Binge eating is one of the most prevalent eating disorders among adults, though there tends to be less media coverage and research about the disorder in comparison to anorexia nervosa and bulimia nervosa.

Eating disorder not otherwise specified (EDNOS) is an eating disorder that does not meet the criteria for: anorexia nervosa, bulimia nervosa, or binge eating. Individuals with EDNOS usually fall into one of three groups: sub-threshold symptoms of anorexia or bulimia, mixed features of both disorders, or extremely atypical eating behaviors that are not characterized by either of the other established disorders.

People with EDNOS have similar symptoms and behaviors to those with anorexia and bulimia, and can face the same dangerous risks.

EDNOS is the most prevalent eating disorder; about 60% of adults treated for eating disorders are diagnosed with EDNOS. EDNOS occurs in both sexes.

Purging disorder is an eating disorder characterized by recurrent purging (self-induced vomiting, misuse of laxatives, diuretics, or enemas) to control weight or shape in the absence of binge eating episodes.

Purging disorder differs from bulimia nervosa (BN) because individuals with purging disorder do not consume a large amount of food before they purge. In current diagnostic systems, purging disorder is a form of Other specified feeding or eating disorder (OSFED). Research indicates that purging disorder may be as common as bulimia nervosa or anorexia nervosa in women, that the syndrome is associated with clinically significant levels of distress, and that it appears to be distinct from bulimia nervosa on measures of hunger and ability to control food intake. Some of the signs of purging disorder are frequent trips to the bathroom directly after a meal, frequent use of laxatives, and obsession over one's appearance and weight. Other signs include swollen cheeks, popped blood vessels in the eyes, and clear teeth which are all signs of excessive vomiting.

Anorexia athletica (sports anorexia), also referred to as hypergymnasia is an eating disorder characterized by excessive and compulsive exercise. An athlete suffering from sports anorexia tends to over exercise to give themselves a sense of having control over their body. Most often, people with the disorder tend to feel they have no control over their lives other than their control of food and exercise. In actuality, they have no control; they cannot stop exercising or regulating food intake without feeling guilty. Generally, once the activity is started, it is difficult to stop because the person is seen as being addicted to the method adopted.

Anorexia athletica is used to refer to "a disorder for athletes who engage in at least one unhealthy method of weight control". Unlike anorexia nervosa, anorexia athletica does not have as much to do with body image as it does with performance. Athletes usually begin by eating more 'healthy' foods, as well as increasing their training, but when people feel like that is not enough and start working out excessively and cutting back their caloric intake until it becomes a psychological disorder.

Hypergymnasia and anorexia athletica are not recognized as mental disorders in any of the medical manuals, such as the ICD-10 or the DSM-IV, nor is it part of the proposed revision of this manual, the DSM-5. If this were the case, there would be a 10–15% increase in mental disorders in sports. A study at the Anorexia Centre at Huddinge Hospital in Stockholm, Sweden showed that sports anorexia can result in mental disorders. The anxiety, stress, and pressure people with sports anorexia put on themselves (as well as the pressure parents and coaches can put on the athlete) can cause mental disorders.

Feeding disorder has been divided into six further sub-types:

1. Feeding disorder of state regulation

2. Feeding disorder of reciprocity (neglect)

3. Infantile anorexia

4. Sensory food aversion

5. Feeding disorder associated with concurrent medical condition

6. Post-traumatic feeding disorder

A few of the medical and psychological conditions that have been known to be associated with this disorder include:

- Gastrointestinal motility disorders

- Oral-motor dysfunction

- Failure to thrive

- Prematurity

- Food allergies

- Sensory problems

- Reflux

- Feeding tube placement

A child that is suffering from malnutrition can have permanently stunted mental and physical development. Getting treatment early is essential and can prevent many of the complications. They can also develop further eating disorders later in life such as anorexia nervosa, or they could become a limited eater—though they could still be a healthy child they may become a picky eater.

Emotional eating is defined as overeating in order to relieve negative emotions. Thus, emotional eating is considered a maladaptive coping strategy. If an individual frequently engages in emotional eating, it can increase the risk of developing other eating disorders, like bulimia and anorexia nervosa. Research has also shown that the presence of an existing eating disorder increases the likelihood that an individual will engage in emotional eating. Given the relationship between serious eating disorders and emotional eating behavior, it is important for clinical psychologists and nutritionists to recognize the signs of emotional eating and provide individuals with treatment. Since emotional eating is utilized to manage negative emotions, treatment necessitates learning healthy and more effective coping strategies.

Whereas vanity involves a quest to aggrandize the appearance, BDD is experienced as a quest to merely normalize the appearance. Although delusional in about one of three cases, the appearance concern is usually nondelusional, an overvalued idea.

The bodily area of focus can be nearly any, yet is commonly face, hair, stomach, thighs, or hips. Some half dozen areas can be a roughly simultaneous focus. Many seek dermatological treatment or cosmetic surgery, which typically do not resolve the distress. On the other hand, attempts at self-treatment, as by skin picking, can create lesions where none previously existed.

BDD shares features with obsessive-compulsive disorder, but involves more depression and social avoidance. BDD often associates with social anxiety disorder. Some experience delusions that others are covertly pointing out their flaws. Cognitive testing and neuroimaging suggest both a bias toward detailed visual analysis and a tendency toward emotional hyperarousal.

Most generally, one experiencing BDD ruminates over the perceived bodily defect up to several hours daily, uses either social avoidance or camouflaging with cosmetics or apparel, repetitively checks the appearance, compares it to that of other persons, and might often seek verbal reassurances. One might sometimes avoid mirrors, repetitively change outfits, groom excessively, or restrict eating.

BDD's severity can wax and wane, and flareups tend to yield absences from school, work, or socializing, sometimes leading to protracted social isolation, with some becoming housebound for extended periods. Social impairment is usually greatest, sometimes approaching avoidance of all social activities. Poor concentration and motivation impair academic and occupational performance. The distress of BDD tends to exceed that of either major depressive disorder or type-2 diabetes, and rates of suicidal ideation and attempts are especially high.

Estimates of prevalence and gender distribution have varied widely via discrepancies in diagnosis and reporting. In American psychiatry, BDD gained diagnostic criteria in the "DSM-IV", but clinicians' knowledge of it, especially among general practitioners, is constricted. Meanwhile, shame about having the bodily concern, and fear of the stigma of vanity, makes many hide even having the concern.

Via shared symptoms, BDD is commonly misdiagnosed as social-anxiety disorder, obsessive-compulsive disorder, major depressive disorder, or social phobia. Correct diagnosis can depend on specialized questioning and correlation with emotional distress or social dysfunction. Estimates place the Body Dysmorphic Disorder Questionnaire's sensitivity at 100% (0% false negatives) and specificity at 92.5% (7.5% false positives).

These are the short term symptoms of patients with diabulimia

- Constant urination

- Constant thirst

- Excessive appetite

- High blood glucose levels (often over 600 mg/dL or 33 mmol/L)

- Weakness

- Fatigue

- Large amounts of glucose in the urine

- Inability to concentrate

- Electrolyte disturbance

- Severe ketonuria, and, in DKA, severe ketonemia

- Low sodium levels