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.

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.

Rather than providing specific diagnostic criteria for EDNOS, the fourth revision of the "Diagnostic and Statistical Manual of Mental Disorders" ("DSM-IV") listed six non-exhaustive example presentations, including individuals who:

1. Meet all criteria for anorexia nervosa except their weight falls within the normal range

2. Meet all criteria for bulimia nervosa except they engage in binge eating or purging behaviors less than twice per week or for fewer than three months

3. Purge after eating small amounts of food while retaining a normal body weight

4. Repeatedly chew and spit out large amounts of food without swallowing

5. Do not meet criteria for binge eating disorder

Despite its subclinical status in "DSM-IV", available data suggest that EDNOS is no less severe than the officially recognized "DSM-IV" eating disorders. In a comprehensive meta-analysis of 125 studies, individuals with EDNOS exhibited similar levels of eating pathology and general psychopathology to those with anorexia nervosa and binge eating disorder, and similar levels of physical health problems as those with anorexia nervosa. Although individuals with bulimia nervosa scored significantly higher than those with EDNOS on measures of eating pathology and general psychopathology, those with EDNOS exhibited more physical health problems than those with bulimia nervosa.

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 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.

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.

NES is sometimes comorbid with excess weight; as many as 28% of individuals seeking gastric bypass surgery were found to suffer from NES in one study. However, not all individuals with NES are overweight. Night eating has been associated with diabetic complications. Many people with NES also experience depressed mood and anxiety disorders.

Night eating syndrome (NES) is an eating disorder, characterized by a delayed circadian pattern of food intake. Although there is some degree of comorbidity with binge eating disorder, it differs from binge eating in that the amount of food consumed in the evening/night is not necessarily objectively large nor is a loss of control over food intake required. It was originally described by Dr. Albert Stunkard in 1955 and is currently included in the other specified feeding or eating disorder category of the DSM-5. Research diagnostic criteria have been proposed and include evening hyperphagia (consumption of 25% or more of the total daily calories after the evening meal) and/or nocturnal awakening and ingestion of food two or more times per week. The person must have awareness of the night eating to differentiate it from the parasomnia sleep-related eating disorder (SRED). Three of five associated symptoms must also be present: lack of appetite in the morning, urges to eat in the evening/at night, belief that one must eat in order to fall back to sleep at night, depressed mood, and/or difficulty sleeping.

NES affects both men and women, between 1 and 2% of the general population, and approximately 10% of obese individuals. The age of onset is typically in early adulthood (spanning from late teenage years to late twenties) and is often long-lasting, with children rarely reporting NES. People with NES have been shown to have higher scores for depression and low self-esteem, and it has been demonstrated that nocturnal levels of the hormones melatonin and leptin are decreased. The relationship between NES and the parasomnia SRED is in need of further clarification. There is debate as to whether these should be viewed as separate diseases, or part of a continuum. Consuming foods containing serotonin has been suggested to aid in the treatment of NES, but other research indicates that diet by itself cannot appreciably raise serotonin levels in the brain. A few foods (for example, bananas) contain serotonin, but they do not affect brain serotonin levels, and various foods contain tryptophan, but the extent to which they affect brain serotonin levels must be further explored scientifically before conclusions can be drawn, and "the idea, common in popular culture, that a high-protein food such as turkey will raise brain tryptophan and serotonin is, unfortunately, false."

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.

Separation anxiety disorder

- excessive stress when separated from home or family

- fear of being alone

- refusal to sleep alone

- clinginess

- excessive worry about safety

- excessive worry about getting lost

- frequent medical complaints with no cause

- refusal to go to school

Selective mutism

- unable to speak in certain social situations, even though they are comfortable speaking at home or with friends

- difficulty maintaining eye contact

- may have blank facial expressions

- stiff body movements

- may have a worrisome personality

- may be incredibly sensitive to sound

- difficulty with verbal and non-verbal expression

- may appear shy, when in reality, they have a fear of people.

Reactive attachment disorder of infancy or early childhood

- withdrawing from others

- aggressive attitude towards peers

- awkwardness or discomfort

- watching others but not engaging in social interaction

Stereotypic movement disorder

- head banging

- nail biting

- hitting or biting oneself

- hand waving or shaking

- rocking back and forth

Children with a tic disorder may exhibit the following symptoms:

- overwhelming urge to make movement

- jerking of arms

- clenching of fists

- excessive eye blinking

- shrugging of shoulders

- kicking

- raising eyebrows

- flaring of nostrils

- production of repetitive noises such as grunting, clicking, moaning, snorting, squealing, or throat clearing

The condition is characterised by aversive reactions to feeding and oral stimulation including Co-Symptoms. It can occur one week after tube insertion.

- Food refusal/Head turning

- Loss of appetite/disinterest

- Oversensitivity for touching, smelling, tasting food

- Nausea

- Gagging

- Retching

- Vomiting

- Anxiety attacks

Postpartum psychosis is not a formal diagnosis, but is widely used to describe a psychiatric emergency that appears to occur in about 1 in a 1000 pregnancies, in which symptoms of high mood and racing thoughts (mania), depression, severe confusion, loss of inhibition, paranoia, hallucinations and delusions begin suddenly in the first two weeks after delivery; the symptoms vary and can change quickly. It is different from postpartum depression and from maternity blues. It may be a form of bipolar disorder. It is important not to confuse psychosis with other symptoms that may occur after delivery, such as delirium. Delirium typically includes a loss of awareness or inability to pay attention.

About half of women who experience postpartum psychosis have no risk factors; but a prior history of mental illness, especially bipolar disorder, a history of prior episodes of postpartum psychosis, or a family history put some at a higher risk.

Postpartum psychosis often requires hospitalization, where treatment is antipsychotic medications, mood stabilizers, and in cases of strong risk for suicide, electroconvulsive therapy.

The most severe symptoms last from 2 to 12 weeks, and recovery takes 6 months to a year. Women who have been hospitalized for a psychiatric condition immediately after delivery are at a much higher risk of suicide during the first year after delivery.

Postpartum blues, commonly known as "baby blues," is a transient postpartum mood disorder characterized by milder depressive symptoms than postpartum depression. This type of depression can occur in up to 80% of all mothers following delivery. Symptoms typically resolve within two weeks. Symptoms lasting longer than two weeks are a sign of a more serious type of depression. Women who experience "baby blues" may have a higher risk of experiencing a more serious episode of depression later on.

Tube dependency is a new clinical phenomenon and isn't recognized as a separate diagnosis yet, thus there is no standardized valid diagnostic inventory to classify it. Tube dependency should be considered in any patient who remains tube-fed despite having the basic ability to ingest food orally and in absence of specific medical reasons to remain tube fed. In this case, assessment by a clinician experienced with eating development, tube management and tube weaning is recommended

There are two known methods that can aid in the possible diagnosis of tube dependency:

1. Observation of affected infants during a feeding situation by experienced clinicians.

2. A multiaxial diagnostic system focused on eating behavior disorders. It consists of five axis, which are compatible with the axis of the DSM-IV and subdivided in currently six feeding (eating behavior) disorders with different origins.

One of the reasons a cat may stop eating is separation anxiety and the emotional stress that results. Moving, gaining or losing housemates or pets, going on vacation, or prolonged boarding are all common situations that pet owners report just prior to the onset of the disease, but it may develop without these conditions existing. Obesity is known to increase the risk of hepatic lipidosis; however, there is no known "official" cause of the disease. Severe anorexia usually precedes the onset of the disease. When the cat has no energy from eating, the liver must metabolize fat deposits in the body into usable energy to sustain life. The cat liver, however, is poor at metabolizing fat, causing a buildup of fat in the cells of the liver, leading to fatty liver. At this point the disease can be diagnosed; however, it will often not be diagnosed, and many animals are euthanized due to improper or no diagnosis.

It is characterized by:

- Obesity

- Growth retardation and retarded sexual development, atrophy or hypoplasia of the gonads, and altered secondary sex characteristics,

- Headaches

- Problems with vision

- polyuria, polydipsia.

It is usually associated with tumors of the hypothalamus, causing increased appetite and depressed secretion of gonadotropin. It seems to affect males mostly.

Many overweight children may appear to have the disorder because of the concurrence of obesity and retarded sexual development; these children have no endocrine disturbances, however, and they mature normally after delayed puberty.

Cat skin disorders are among the most common health problems in cats.

Skin disorders in cats have many causes, and many of the common skin disorders that afflict people have a counterpart in cats. The condition of a cat's skin and coat can also be an important indicator of its general health. Skin disorders of cats vary from acute, self-limiting problems to chronic or long-lasting problems requiring life-time treatment. Cat skin disorders may be grouped into categories according to the causes.

Typically, initial signs and symptoms of this disorder occur during infancy or early childhood and can include feeding difficulties, lethargy, hypoglycemia, hypotonia, liver problems, and abnormalities in the retina. Muscle pain, a breakdown of muscle tissue, and abnormalities in the nervous system that affect arms and legs (peripheral neuropathy) may occur later in childhood. There is also a risk for complications such as life-threatening heart and breathing problems, coma, and sudden unexpected death. Episodes of LCHAD deficiency can be triggered by periods of fasting or by illnesses such as viral infections.

Tricho-hepato-enteric syndrome is one particular form of intractable diarrhea of infancy, presenting typically in the first month of life. These babies were usually born small for their age and continue to experience failure to thrive, usually with a final short stature. Typical facial features include prominent forehead and cheeks, a broad nasal root and widely spaced eyes (hypertelorism). Their hairs are woolly, easily removed and poorly pigmented. Liver disease is mainly present as cirrhosis or fibrosis, and staining might reveal high iron content of the liver cells (consistent with hemochromatosis). Most evaluated patients had some degree of decrease in intelligence.

Prader–Willi syndrome is frequently associated with a constant, extreme, ravenous insatiable appetite which persists no matter how much the patient eats, often resulting in morbid obesity. Caregivers need to strictly limit the patients' access to food, usually by installing locks on refrigerators and on all closets and cabinets where food is stored. It is the most common genetic cause of morbid obesity in children. There is currently no consensus as to the cause for this symptom, although genetic abnormalities in chromosome 15 disrupt the normal functioning of the hypothalamus. Given that the hypothalamus arcuate nucleus regulates many basic processes, including appetite, there may well be a link. In the hypothalamus of people with PWS, nerve cells that produce oxytocin, a hormone thought to contribute to satiety, have been found to be abnormal.

People with Prader–Willi syndrome have high ghrelin levels, which are thought to directly contribute to the increased appetite, hyperphagia, and obesity seen in this syndrome. Cassidy states the need for a clear delineation of behavioral expectations, the reinforcement of behavioural limits and the establishment of regular routines.

The main mental health difficulties experienced by people with PWS include compulsive behaviour (usually manifested in skin picking) and anxiety. Psychiatric symptoms, for example, hallucinations, paranoia and depression, have been described in some cases and affect approximately 5–10% of young adults. Patients are also often extremely stubborn and prone to anger. Psychiatric and behavioural problems are the most common cause of hospitalization.

It is typical for to 70–90% of affected individuals to develop behavioral patterns in early childhood. Aspects of these patterns can include stubbornness, temper tantrums, controlling and manipulative behavior, difficulty with change in routine, and compulsive-like behaviors.

Although confirmation of a specific genetic marker is in a significant number of individuals, there are no tests to clearly determine if this is what a person has. As a 'syndrome' a diagnosis is typically given for children upon confirmation of the presence of several 'symptoms' listed below. Symptoms are Intrauterine Growth Restriction (IUGR) combined with some of the following:

- Often small for gestational age (SGA) at birth (birth weight less than 2.8 kg)

- Feeding problems: the baby is uninterested in feeding and takes only small amounts with difficulty

- Hypoglycemia

- Excessive sweating as a baby, especially at night, and a greyness or pallor of the skin. This may be a symptom of hypoglycemia

- Triangular shaped face with a small jaw and a pointed chin that tends to lessen slightly with age. The mouth tends to curve down

- A blue tinge to the whites of the eyes in younger children

- Head circumference may be of normal size and disproportionate to a small body size

- Wide and late-closing fontanelle

- Clinodactyly

- Body asymmetry: one side of the body grows more slowly than the other

- Continued poor growth with no "catch up" into the normal centile lines on growth chart

- Precocious puberty (occasionally)

- Low muscle tone

- Gastroesophageal reflux disease

- A striking lack of fat

- Late closing of the opening between the heart hemispheres

- Constipation (sometimes severe)

The average adult height for patients without growth hormone treatment is 4'11" for males and 4'7" for females.

Fancy goldfish are among the fish most commonly affected by this disorder. The disease may be caused by intestinal parasites or by constipation induced by high nitrate levels from over feeding.