It is not clear exactly what causes esophageal spasms. Sometimes esophageal spasms start when someone eats hot or cold foods or drinks. However, they can also occur with eating or drinking. The increased release of acetylcholine may also be a factor, but the triggering event is not known.

Incidence of achalasia has risen to approximately 1.6 per 100,000 in some populations. Disease affects mostly adults between ages 30s and 50s.

Achalasia (; "" + "-chalasia" "no relaxation") is a failure of smooth muscle fibers to relax, which can cause a sphincter to remain closed and fail to open when needed. Without a modifier, "achalasia" usually refers to achalasia of the esophagus, which is also called esophageal achalasia, achalasia cardiae, cardiospasm, and esophageal aperistalsis. Achalasia can happen at various points along the gastrointestinal tract; achalasia of the rectum, for instance, may occur in Hirschsprung's disease.

Esophageal achalasia is an esophageal motility disorder involving the smooth muscle layer of the esophagus and the lower esophageal sphincter (LES). It is characterized by incomplete LES relaxation, increased LES tone, and lack of peristalsis of the esophagus (inability of smooth muscle to move food down the esophagus) in the absence of other explanations like cancer or fibrosis.

Achalasia is characterized by difficulty in swallowing, regurgitation, and sometimes chest pain. Diagnosis is reached with esophageal manometry and barium swallow radiographic studies. Various treatments are available, although none cures the condition. Certain medications or Botox may be used in some cases, but more permanent relief is brought by esophageal dilatation and surgical cleaving of the muscle (Heller myotomy).

The most common form is primary achalasia, which has no known underlying cause. It is due to the failure of distal esophageal inhibitory neurons. However, a small proportion occurs secondary to other conditions, such as esophageal cancer or Chagas disease (an infectious disease common in South America). Achalasia affects about one person in 100,000 per year. There is no gender predominance for the occurrence of disease.

Nutcracker esophagus, or hypertensive peristalsis, is a disorder of the movement of the esophagus characterized by contractions in the smooth muscle of the esophagus in a normal sequence but at an excessive amplitude or duration. Nutcracker esophagus is one of several motility disorders of the esophagus, including achalasia and diffuse esophageal spasm. It causes difficulty swallowing, or dysphagia, to both solid and liquid foods, and can cause significant chest pain; it may also be asymptomatic. Nutcracker esophagus can affect people of any age, but is more common in the sixth and seventh decades of life. The diagnosis is made by an esophageal motility study (esophageal manometry), which evaluates the pressure of the esophagus at various points along its length. The term "nutcracker esophagus" comes from the finding of increased pressures during peristalsis, with a diagnosis made when pressures exceed 180 mmHg; this has been likened to the pressure of a mechanical nutcracker. The disorder does not progress, and is not associated with any complications; as a result, treatment of nutcracker esophagus targets control of symptoms only.

Esophageal spasm is rare. Often, symptoms that may suggest esophageal spasm are the result of another condition such as gastroesophageal reflux disease (GERD) or achalasia. The symptoms can also include dysphagia, regurgitation, noncardiac chest pain, heartburn, globus pharyngis (which is a feeling that something is stuck in the throat) or a dry cough.

The patient is generally sent for a GI, pulmonary, or ENT, depending on the suspected underlying cause. Consultations with a speech therapist and registered dietitian nutritionist (RDN) are also needed, as many patients may need dietary modifications such as thickened fluids.

Nutcracker esophagus is a benign, nonprogressive condition, meaning it is not associated with significant complications. Patients are usually reassured by their physicians that the disease is unlikely to worsen. However, the symptoms of chest pain and dysphagia may be severe enough to require treatment with medications, and rarely, surgery.

The initial step of treatment focuses on reducing risk factors. While weight reduction may be useful in reducing symptoms, the role of acid suppression therapy to reduce esophageal reflux is still uncertain. Very cold and very hot beverages may trigger esophageal spasms.

Medical therapy for nutcracker esophagus includes the use of calcium-channel blockers, which relax the lower esophageal sphincter (LES) and palliate the dysphagia symptoms. Diltiazem, a calcium-channel blocker, has been used in randomized control studies with good effect. Nitrate medications, including isosorbide dinitrate, given before meals, may also help relax the LES and improve symptoms. The inexpensive generic combination of belladonna and phenobarbital (Donnatal and other brands) may be taken three times daily as a tablet to prevent attacks or, for patients with only occasional episodes, as an elixir at the onset of symptoms. Phosphodiesterase inhibitors, such as sildenafil, can be given to reduce symptoms, particularly pain, but small trials have not been able to demonstrate clinical improvement. Finally, trazodone, an antidepressant that reduces visceral sensitivity, has also been shown to reduce chest pain symptoms in patients with nutcracker esophagus.

Endoscopic therapy with botulinum toxin, known also as Botox, can also be used to improve dysphagia which stabilizes unintentional weight loss, but the effect has limited effect on other symptoms, including pain, while also being a temporary treatment lasting a few weeks. Finally, pneumatic dilatation of the esophagus, which is an endoscopic technique where a high-pressure balloon is used to stretch the muscles of the LES, can be performed to improve symptoms, but again no clinical improvement is seen in regards to motility.

If there is dysphagia to both solids and liquids, then it is most likely a motility problem. If there is dysphagia initially to solids but progresses to also involve liquids, then it is most likely a mechanical obstruction. Once a distinction has been made between a motility problem and a mechanical obstruction, it is important to note whether the dysphagia is intermittent or progressive. An intermittent motility dysphagia likely can be diffuse esophageal spasm (DES) or nonspecific esophageal motility disorder (NEMD). Progressive motility dysphagia disorders include scleroderma or achalasia with chronic heartburn, regurgitation, respiratory problems, or weight loss. Intermittent mechanical dysphagia is likely to be an esophageal ring. Progressive mechanical dysphagia is most likely due to peptic stricture or esophageal cancer.

Esophageal diseases can derive from congenital conditions, or they can be acquired later in life.

Many people experience a burning sensation in their chest occasionally, caused by stomach acids refluxing into the esophagus, normally called heartburn. Extended exposure to heartburn may erode the lining of the esophagus, leading potentially to Barrett's esophagus which is associated with an increased risk of adenocarcinoma most commonly found in the distal one-third of the esophagus.

Some people also experience a sensation known as globus esophagus, where it feels as if a ball is lodged in the lower part of the esophagus.

The following are additional diseases and conditions that affect the esophagus:

- Achalasia

- Acute esophageal necrosis

- Barrett's esophagus

- Boerhaave syndrome

- Caustic injury to the esophagus

- Chagas disease

- Diffuse esophageal spasm

- Esophageal atresia and Tracheoesophageal fistula

- Esophageal cancer

- Esophageal dysphagia

- Esophageal varices

- Esophageal web

- Esophagitis

- GERD

- Hiatus hernia

- Jackhammer esophagus (hypercontractile peristalsis)

- Killian–Jamieson diverticulum

- Mallory-Weiss syndrome

- Neurogenic dysphagia

- Nutcracker esophagus

- Schatzki's ring

- Zenker's Diverticulum

Incidence of hiatal hernias increases with age; approximately 60% of individuals aged 50 or older have a hiatal hernia. Of these, 9% are symptomatic, depending on the competence of the lower esophageal sphincter (LES). 95% of these are "sliding" hiatus hernias, in which the LES protrudes above the diaphragm along with the stomach, and only 5% are the "rolling" type (paraesophageal), in which the LES remains stationary, but the stomach protrudes above the diaphragm.

Hiatus hernia are most common in North America and Western Europe and rare in rural African communities. Some have proposed that insufficient dietary fiber and the use of a high sitting position for defecation may increase the risk.

Megaesophagus is rare in horses. It is more frequently reported in Friesian horses than in other breeds. Congenital megaesophagus is usually identified when a foal begins to eat solid food from the ground; prior to this, as the foal nurses milk from its mother, the milk passes easily down into the stomach. The most common signs are difficulty swallowing (dysphagia) and inhalational pneumonia.

Megaesophagus can also be a symptom of the disease myasthenia gravis. Myasthenia gravis is a neuromuscular disease where the primary symptom is weakness in various body parts of the dog. However, when myasthenia gravis occurs in older dogs it is thought of as an immune-mediated disease. Often when myasthenia gravis is diagnosed in older dogs the first symptom the dog may manifest is megaesophagus.

Myasthenia gravis occurs when acetylcholine receptors (nicotinic acetylcholine receptors) fail to function properly, so that the muslce is not stimulated to contract.

Oesophageal diseases include a spectrum of disorders affecting the oesophagus. The most common condition of the oesophagus in Western countries is gastroesophageal reflux disease, which in chronic forms is thought to result in changes to the epithelium of the oesophagus, known as Barrett's oesophagus.

Acute disease might include infections such as oesophagitis, trauma caused ingestion of corrosive substances, or rupture of veins such as oesophageal varices, Boerhaave syndrome or Mallory-Weiss tears. Chronic diseases might include congenital diseases such as Zenker's diverticulum and esophageal webbing, and oesophageal motility disorders including the nutcracker oesophagus, achalasia, diffuse oesophageal spasm, and oesophageal stricture.

Oesophageal disease may result in a sore throat, throwing up blood, difficulty swallowing or vomiting. Chronic or congenital diseases might be investigated using barium swallows, endoscopy and biopsy, whereas acute diseases such as reflux may be investigated and diagnosed based on symptoms and a medical history alone.

In the great majority of cases, sufferers experience no life-altering discomfort, and no treatment is required. If there is pain or discomfort, 3 or 4 sips of room temperature water will usually relieve the pain. Symptomatic patients should elevate the head of their beds and avoid lying down directly after meals. If the condition has been brought on by stress, stress reduction techniques may be prescribed, or if overweight, weight loss may be indicated. Antisecretory drugs like proton pump inhibitors and H receptor blockers can be used to reduce acid secretion. Medications that reduce the lower esophageal sphincter (LES) pressure should be avoided.

However, in some unusual instances, as when the hiatal hernia is unusually large, or is of the paraesophageal type, it may cause esophageal stricture or severe discomfort. About 5% of hiatus hernias are paraesophageal. If symptoms from such a hernia are severe for example if chronic acid reflux threatens to severely injure the esophagus or is causing Barrett's esophagus, surgery is sometimes recommended. However surgery has its own risks including death and disability, so that even for large or paraesophageal hernias, watchful waiting may on balance be safer and cause fewer problems than surgery. Complications from surgical procedures to correct a hiatus hernia may include gas bloat syndrome, dysphagia (trouble swallowing), dumping syndrome, excessive scarring, and rarely, achalasia. Surgical procedures sometimes fail over time, requiring a second surgery to make repairs.

One surgical procedure used is called Nissen fundoplication. In fundoplication, the gastric fundus (upper part) of the stomach is wrapped, or plicated, around the inferior part of the esophagus, preventing herniation of the stomach through the hiatus in the diaphragm and the reflux of gastric acid. The procedure is now commonly performed laparoscopically. With proper patient selection, laparoscopic fundoplication recent studies have indicated relatively low complication rates, quick recovery, and relatively good long term results.

Gastric diseases refer to diseases affecting the stomach. Inflammation of the stomach by infection from any cause is called gastritis, and when including other parts of the gastrointestinal tract called gastroenteritis. When gastritis persists in a chronic state, it is associated with several diseases, including atrophic gastritis, pyloric stenosis, and gastric cancer. Another common condition is gastric ulceration, peptic ulcers. Ulceration erodes the gastric mucosa, which protects the tissue of the stomach from the stomach acids. Peptic ulcers are most commonly caused by a bacterial "Helicobacter pylori" infection.

As well as peptic ulcers, vomiting blood may result from abnormal arteries or veins that have ruptured, including Dieulafoy's lesion and Gastric antral vascular ectasia. Congenital disorders of the stomach include pernicious anaemia, in which a targeted immune response against parietal cells results in an inability to absorb vitamin B12. Other common symptoms that stomach disease might cause include indigestion or dyspepsia, vomiting, and in chronic disease, digestive problems leading to forms of malnutrition. In addition to routine tests, an endoscopy might be used to examine or take a biopsy from the stomach.

As gas is the usual trigger, eating foods that a person is intolerant to can make symptoms more severe.

Smoking increases the risk of developing gastric cancer significantly, from 40% increased risk for current smokers to 82% increase for heavy smokers. Gastric cancers due to smoking mostly occur in the upper part of the stomach near the esophagus. Some studies show increased risk with alcohol consumption as well.

Dietary factors are not proven causes, but some foods including smoked foods, salt and salt-rich foods, red meat, processed meat, pickled vegetables, and bracken are associated with a higher risk of stomach cancer. Nitrates and nitrites in cured meats can be converted by certain bacteria, including "H. pylori", into compounds that have been found to cause stomach cancer in animals.

Fresh fruit and vegetable intake, citrus fruit intake, and antioxidant intake are associated with a lower risk of stomach cancer. A Mediterranean diet is associated with lower rates of stomach cancer, as is regular aspirin use.

Obesity is a physical risk factor that has been found to increase the risk of gastric adenocarcinoma by contributing to the development of gastroesophageal reflux disease (GERD). The exact mechanism by which obesity causes GERD is not completely known. Studies hypothesize that increased dietary fat leading to increased pressure on the stomach and the lower esophageal sphincter, due to excess adipose tissue, could play a role, yet no statistically significant data has been collected. However, the risk of gastric cardia adenocarcinoma, with GERD present, has been found to increase more than 2 times for an obese person. There is a correlation between iodine deficiency and gastric cancer.

Treatment of the primary gastroenterological distress is the first concern, mitigation of gastric symptoms will also alleviate cardiac distress.

- Anticholinergics, magnesium, or sodium (to raise blood pressure) supplements

- Anticonvulsants have eliminated all symptoms in some RS sufferers; Lorazepam, Oxcarbazepine increase GI motility, reduce vagus "noise" (sodium channel blocking believed to contribute to positive effects)

- Alpha blockers may increase gi motility if that is an issue, also 5 mg to 10 mg amitriptyline if motility is an issue that can't be solved by other methods

- antigas - simethicone, beano, omnimax reduces epigastric pressure

- Antacids - nexium, tums, Pepcid AC, rolaids, etc. reduces acid reflux in the case of hiatal hernia or other esophageal type RS.

- Vagusectomy

- Beta blockers - reduces contractility and automaticity of the heart which reduces irregular rhythms but also lowers blood pressure when symptoms occur, and further reduces perfusion ex: Atenolol, this will control disarrhythmia, but can precipitate Prinzmetal Angina and Heart block substantially.

The resulting syndrome depends on the structure affected.

Examples of vascular stenotic lesions include:

- Intermittent claudication (peripheral artery stenosis)

- Angina (coronary artery stenosis)

- Carotid artery stenosis which predispose to (strokes and transient ischaemic episodes)

- Renal artery stenosis

The types of stenoses in heart valves are:

- Pulmonary valve stenosis, which is the thickening of the pulmonary valve, therefore causing narrowing

- Mitral valve stenosis, which is the thickening of the mitral valve (of the left heart), therefore causing narrowing

- Tricuspid valve stenosis, which is the thickening of the tricuspid valve (of the right heart), therefore causing narrowing

- Aortic valve stenosis, which is the thickening of the aortic valve, therefore causing narrowing

Stenoses/strictures of other bodily structures/organs include:

- Pyloric stenosis (gastric outflow obstruction)

- Lumbar, cervical or thoracic spinal stenosis

- Subglottic stenosis (SGS)

- Tracheal stenosis

- Obstructive jaundice (biliary tract stenosis)

- Bowel obstruction

- Phimosis

- Non-communicating hydrocephalus

- Stenosing tenosynovitis

- Atherosclerosis

- Esophageal stricture

- Achalasia

- Prinzmetal angina

- Vaginal stenosis

A stenosis is an abnormal narrowing in a blood vessel or other tubular organ or structure. It is also sometimes called a stricture (as in urethral stricture).

Stricture as a term is usually used when narrowing is caused by contraction of smooth muscle (e.g., achalasia, prinzmetal angina); stenosis is usually used when narrowing is caused by lesion that reduces the space of lumen (e.g., atherosclerosis). The term coarctation is another synonym, but is commonly used only in the context of aortic coarctation.

Restenosis is the recurrence of stenosis after a procedure. The term is from Ancient Greek στενός, "narrow".

Prognosis is poor, however, current analysis suggests that those associated with thymoma, benign or malignant, show a less favorable prognosis (CASPR2 Ab positive).

5 had positive response to immunotherapy and tumor therapy, 10 partial response, and 6 no response. Eventually 5 patients died; all had a tumor or additional paraneoplastic symptoms related to onconeuronal antibodies. Coexistence of onconeuronal antibodies predicted a poor outcome.

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.

There are various other psychological issues that 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. 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. These comorbid disorders themselves have multiple differential diagnoses, such as depression which may be caused by such disparate causes such as Lyme disease or hypothyroidism.

- Body dysmorphic disorder (BDD) is listed as a somatoform disorder that affects up to 2% of the population. BDD is characterized by excessive rumination over an actual or perceived physical flaw. BDD has been diagnosed equally among men and women. While BDD has been misdiagnosed as anorexia nervosa, it also occurs comorbidly in 25% to 39% of AN cases.

BDD is a chronic and debilitating condition which may lead to social isolation, major depression, suicidal ideation and attempts. Neuroimaging studies to measure response to facial recognition have shown activity predominately in the left hemisphere in the left lateral prefrontal cortex, lateral temporal lobe and left parietal lobe showing hemispheric imbalance in information processing. There is a reported case of the development of BDD in a 21 year old male following an inflammatory brain process. Neuroimaging showed the presence of new atrophy in the frontotemporal region.

- Emetophobia is an anxiety disorder characterized by an intense fear of vomiting. A person so afflicted may develop rigorous standards of food hygiene, such as not touching food with their hands. They may become socially withdrawn to avoid situations which in their perception may make them vomit. Many who suffer from emetophobia are diagnosed with anorexia or self-starvation. In severe cases of emetophobia they may drastically reduce their food intake.

- Food avoidance emotional disorder is an eating disorder that affects children which involves a fear of eating which is not accompanied by a fear of weight gain which may be misdiagnosed as anorexia nervosa.

- phagophobia is an anxiety disorder characterized by a fear of eating, it is usually initiated by an adverse experience while eating such as choking or vomiting. Individuals with this disorder may present with complaints of pain while swallowing. There have been cases of it being misdiagnosed as AN. A similar phobic anxiety disorder, swallowing phobia may also lead to a misdiagnosis of anorexia nervosa; such individuals do not want to lose weight but typically want to put weight back on that they have lost due to their phobia.

The distinction between the diagnoses of anorexia nervosa, bulimia nervosa and eating disorder not otherwise specified (EDNOS) is often difficult to make as there is considerable overlap between patients diagnosed with these conditions. Seemingly minor changes in a patient's overall behavior or attitude can change a diagnosis from "anorexia: binge-eating type" to bulimia nervosa. It is not unusual for a person with an eating disorder to "move through" various diagnoses as his or her behavior and beliefs change over time.