Eating disorders and development

Eating disorders typically peak at specific periods in development, notably sensitive and transitional periods such as puberty. Feeding and eating disorders in childhood are often the result of a complex interplay of organic and non-organic factors. Medical conditions, developmental problems and temperament are all strongly correlated with feeding disorders, but important contextual features of the environment and parental behavior have also been found to influence the development of childhood eating disorders. Given the complexity of early childhood eating problems, consideration of both biological and behavioral factors is warranted for diagnosis and treatment.

Revisions in the DSM-5 have attempted to improve diagnostic utility for clinicians working with feeding and eating disorder patients. In the DSM-5, diagnostic categories are less defined by age of patient, and guided more by developmental differences in presentation and expression of eating problems.

History
Avoidant/Restrictive Intake Disorder (ARFID) was added to the DSM-5 to better clinically describe a subset of eating disorder patients who previously had been diagnosed with Eating Disorder Not Otherwise Specified (EDNOS), a much broader diagnostic category with less clinical utility. Although more studies need to be conducted, initial studies are validating ARFID as a distinct eating disorder with criteria separate from Anorexia (AN) and Bulimia (BN). Patients meeting criteria for ARFID typically have a longer history of symptoms prior to diagnosis and an earlier onset than AN or BN patients. They are also more likely to have a co-morbid medical condition or anxiety disorder.

Diagnostic criteria
An eating or feeding disturbance (e.g., apparent lack of interest in eating or food; avoidance based on sensory characteristics of food; concern about aversive consequences of eating)as manifested by persistent failure to meet appropriate nutritional and/or energy needs associated with one (or more)of the following:

1. Significant weight loss (or failure to achieve expected weight gain or faltering growth in children). 2. Significant nutritional deficiency. 3. Dependence on enteral feeding or oral nutritional supplements. 4. Marked interference with psychosocial functioning. The disturbance is not better explained by a lack of available food or by an associated culturally sanctioned practice. The eating disturbance does not occur exclusively during the course of anorexia nervosa or bulimia nervosa, and there is no evidence of a disturbance in the way in which one's body weight or shape is experienced. The eating disturbance is not attributable to a current medical condition or not better explained by another mental disorder. When the eating disturbance occurs in the context of another condition or disorder, the severity of the eating disturbance exceeds that routinely associated with the condition or disorder and warrants additional clinical attention

Recent research suggests that patients meeting criteria for ARFID typically have a longer history of symptoms prior to diagnosis, and an earlier onset than AN or BN patients. Selective eating is persistent in ARFID patients, typically beginning in infancy or early childhood. In one recent study, they were also more likely to have a co-morbid medical condition or anxiety disorder, but less likely to have a mood disorder. At present, there is not sufficient evidence that ARFID precedes the development of a later eating disorder.

Diagnostic history
Pica is an eating disorder characterized by the ingestion of non-food or non-nutritive substances. The DSM-5 criteria for Pica are as follows:

Diagnostic criteria

 * Persistent eating of nonnutritive, nonfood substances over a period of at least 1 month.
 * The eating of nonnutritive, nonfood substances is inappropriate to the developmental level of the individual.
 * The eating behavior is not part of a culturally supported or socially normative practice.
 * If the eating behavior occurs in the context of another mental disorder (e.g., intellectual disability [intellectual developmental disorder], autism spectrum disorder, schizophrenia) or medical condition (including pregnancy), it is sufficiently severe to warrant additional clinical attention.

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For Pica to be considered, the eating of non-food items must be inappropriate to the child's developmental level, with a minimum age of two, and no upper age limit. Pica typically presents in children, but the DSM-5 specifies that it can be diagnosed at any age. Pica is most often a co-morbid condition of children with retardation or developmental disorders, but can also present as a symptom in a broader range of troubled behavior or disorders. For example, Pica is sometimes seen in individuals with schizophrenia.

Diagnostic history
Rumination disorder (RD) is an eating disturbance characterized by the regurgitation of partially swallowed or digested food. The following are the DSM-5 criteria for RD:


 * Repeated regurgitation of food over a period of at least 1 month. Regurgitated food may be re-chewed, re-swallowed, or spit out.
 * The repeated regurgitation is not attributable to an associated gastrointestinal or other medical condition (e.g., gastroesophageal reflux, pyloric stenosis).
 * The eating disturbance does not occur exclusively during the course of anorexia nervosa, bulimia nervosa, binge-eating disorder, or avoidant/restrictive food intake disorder.
 * If the symptoms occur in the context of another mental disorder (e.g., intellectual disability [intellectual developmental disorder] or another neurodevelopmental disorder), they are sufficiently severe to warrant additional clinical attention.

Like Pica, RD most often occurs in children with mental retardation or developmental disorders. While rumination most often presents in children, the DSM-5 specifies that it can be diagnosed at any age. RD often presents slightly different in older children and adolescents in that they are less likely to re-chew the food that is brought up, and more likely to spit it out. Like Pica, rumination may also be a symptom of other disorders. For example, rumination is often a characteristic behavior of individuals with Anorexia or Bulimia. It has also been correlated with other disorders and symptoms such as anxiety and OCD.

Diagnostic History
Anorexia nervosa is characterized by the severe restriction of food intake that results in a significant weight loss. There are two subtypes of Anorexia, Restricting Type and Binge-Eating/Purging Type. While historically researchers have found that Anorexia typically begins during puberty, recent epidemiological studies have found that the average age of onset of Anorexia Nervosa has moved from the previously from an average age of onset of 13-17 to a current younger age of onset of 9 -12. Among individuals with an eating disorder, 86% report the onset of the eating disorder by age 20, and 43% report the onset between the ages of 16 and 20.6. Corresponding with the age of onset, 95% of the population with current eating disorders are between the ages of 12 and 25.

Diagnostic criteria
Anorexia is characterized by a significant reduction in energy intake which leads to a low body weight given age, sex, development, and physical health considerations. Anorexia has two subtypes: the restricting type and the purging type. This is based on whether an individual engages in or does not engage in bingeing and purging behaviors.
 * Individuals with anorexia also experience a significant fear of weight gain or engage in behaviors that interfere with weight gain.
 * The illness is also characterized by a disturbance in body image, a significant focus and evaluation of self based on body weight, and/or lack of recognition of the consequences and seriousness of the current low body weight.
 * Intense fear of gaining weight or of becoming fat, or persistent behavior that interferes with weight gain, even though at a significantly low weight.

Anorexia is characterized as mild, moderate, severe, or extreme based on the extent of weight loss.

Bulimia nervosa
Bulimia nervosa is characterized by episodes of binge eating followed by inappropriate compensatory behaviors.

Diagnostic history
Similar to Anorexia, Bulimia typically begins during adolescence, though the average age of onset is somewhat later than that of anorexia. Onset before puberty and after age 40 is atypical.

Diagnostic criteria
Bulimia is characterized by repeated episodes of binge eating following but the use of inappropriate compensatory behaviors.
 * The binge eating and compensatory behaviors occur recurrently
 * An individual experiences a sense of lack of control during the binge eating.
 * Self evaluation is highly influenced by body image and body perceptions.

The disorder can be characterized as mild, moderate, severe, or extreme based on the number of compensatory behaviors per week. .

Diagnostic history
Binge eating disorder was added as an eating disorder diagnosis in DSM-V. Previously individuals with Binge Eating Disorder had been classified under Eating Disorder Not Otherwise Specified. Due to the recency of the diagnosis, less research is currently available on Binge Eating Disorder compared to the other categories of eating disorders. The average age of onset is reported to be 25-years-old.

Diagnostic criteria
Binge Eating disorder is characterized by repeated binge eating episodes. This includes:
 * Eating an objectively large amount of food in a short period of time.
 * Experiencing a sense of lack of control while eating.
 * Feeling self-deprecating based on eating behavior.

The severity is classified by the number of binge eating episodes per week.