Section D - Eating disorders
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Eating disorders are characterized by severely disturbed eating behaviours. They typically begin in adolescence or young adulthood and affect women ten times more than men.1,7 According to recent research studies, prevalence of the most common eating disorders is 0.3-1% for anorexia nervosa and perhaps three times that for bulimia nervosa.7,101,102 Prevalence of completely defined anorexia nervosa among young females and males respectively is 0.04% and 0%; for bulimia nervosa, prevalence is 0.3% among young females and 0.2% among young males.103 While binge eating disorder is more common in all age groups, anorexia nervosa and bulimia nervosa are more disabling and more often become a subject of medical attention. Thus, the two most common, well-defined and disabling eating disorders are discussed in this section.
Anorexia nervosa is an eating disorder characterized by refusal to maintain normal body weight. Bulimia nervosa is an eating disorder characterized by eating excessive amounts of food in one sitting and then trying to compensate for the over-eating by ridding the body of the food.
Individuals with anorexia nervosa or bulimia nervosa are similar in terms of their disturbed perception in body shape and weight, in their level of dissatisfaction with their bodies, and in their fear of gaining weight. However, individuals with anorexia nervosa often feel in control of their eating and body weight, whereas individuals with bulimia nervosa feel out of control. In addition, individuals with bulimia nervosa are often within normal body weight, while individuals with anorexia nervosa are generally below the healthy weight range.
Individuals with an eating disorder often have a perfectionistic attitude toward school or work, low self-esteem, and distorted body image. Female athletes under pressure to be thin (e.g., gymnasts, swimmers) are especially vulnerable. Although the causes of developing an eating disorder are unknown, a variety of factors are likely involved. Society's views and the media tend to portray the message that thinness is attractive, which may contribute to a distorted body image. First-degree relatives of individuals with an eating disorder are more likely to develop an eating disorder, which suggests the disorders may be genetically predisposed.7,104- Finally, individuals with other emotional or psychological disorders, particularly substance abuse, personality disorders, or affective disorders (depression), are at higher risk of developing an eating disorder.
Treatment generally involves a combination of nutrition education and psychotherapy, including individual and family counseling. Medication may also be useful. Treatment is most effective if started early in the course of the disorder.105
There are two subtypes of anorexia nervosa: the first type is restricting type, in which the individual participates in dieting, fasting, and/or excessive exercise to achieve weight loss and does not regularly engage in binge-eating or purging behaviour (self-induced vomiting or misuse of laxatives, diuretics, or enemas); the second type is binge-eating/purging type, in which the individual regularly engages in binge-eating and/or purging behaviour (at least weekly).7 The ICD10 criteria for anorexia nervosa includes starvation and exercise as the main components of anorexia nervosa (and binging and purging are not considered); binging and purging behaviours are, however, included in the ICD10 criteria for bulimia nervosa.6 Therefore, although it is recognized that both types of the disorder may alternate with each other, the health state described in this section represents an individual with restricting type anorexia nervosa.
The functional limitations associated with binging and purging behaviours are described in the health state for an individual with bulimia nervosa, in accordance with the ICD10. It should be noted that many individuals have combinations of eating disorder symptoms that may not be sufficient for a diagnosis of anorexia nervosa or bulimia nervosa; these individuals are therefore diagnosed as "Eating disorder not otherwise specified."7
Part 1 - Anorexia nervosa
Anorexia nervosa is a mental disorder occurring predominantly in females (90% of cases or more),7 and is characterized by refusal to maintain normal body weight, intense fear of becoming obese that does not diminish despite weight loss, and distorted body image resulting in a feeling of being fat. It is one of the most common psychiatric conditions in young women.106
Anorexia nervosa affects between 0.3% and 1% of women.101,102 Onset is typically in mid- to late-adolescence, with behaviour likely beginning as innocent dieting. Gradually, weight loss becomes an obsession and progresses to extreme and unhealthy weight loss. The individual will starve him/herself and yet still exercise excessively to continue losing weight. Despite extreme weight loss, the individual still views him/herself as fat, becomes socially withdrawn and preoccupied with food. Suicide attempts occur in about 20-30% of subjects.107 Course and symptom severity is extremely variable; some individuals suffer a single episode, others fluctuate between weight gain and relapse, and some experience chronic symptoms over many years.7 At some point during the course of anorexia nervosa, over 50% of individuals will develop bulimic symptoms, typically within the first five years,108 although this course will not be described here. Prevention measures are not known at this time.
The DSM-IV clinically diagnoses anorexia nervosa if the following criteria are met: refusal to maintain a minimally normal body weight (body weight less than 85% of that expected) or failure to make expected weight gain during growth periods; intense fear of gaining weight or becoming fat; a distorted view of one's body weight or shape, unnecessary influence on self-evaluation, or denial of the seriousness of their low body weight; and amenorrhea—absence of at least three consecutive menstrual cycles (in postmenarcheal females).7
No specific cause of anorexia nervosa has been identified; it is likely that the causes of anorexia nervosa are due to multiple factors. There is increased risk among first-degree biological relatives of individuals with anorexia nervosa,7,104 suggesting a genetic component. Society's views of thinness may also contribute. Personality variables (i.e., perfectionism) may influence or be a consequence of anorexia nervosa.109 Prognosis is improved with early detection and intervention. Approximately half of those who fully develop the symptoms of anorexia nervosa recover within five years;110 an estimated 5% to 20% will eventually die from complications related to anorexia nervosa.7,111 The malnutrition that results from anorexia denies the body of essential nutrients it needs to function normally, and therefore it slows down its processes to conserve energy. Menarche may be delayed in prepubertal females.7 Starvation can also affect most major organ systems. Estrogen levels are low. Constipation, abdominal pain, lethargy, bradycardia, and cold intolerance are also experienced. Electrolyte imbalance is one of the most dangerous sequelae.112 Over time, reproductive problems, osteoporosis, continued low BMI, and major depression may arise. Death may result due to suicide, starvation, or electrolyte imbalances.7
Treatment generally involves a comprehensive approach: individual therapy, family therapy, behaviour modification, and nutritional rehabilitation, with weight gain as the ultimate goal.105 Antidepressants may be helpful if the individual is depressed. Parents are considered a vital part of the treatment process. Inpatient treatment may be necessary to restore weight and address physiological sequelae of starvation (i.e., fluid and electrolyte imbalances), particularly if the individual is more than 25% below ideal body weight or has been ill for more than two years. Relapse rates are approximately 35%.113,114 Self-directedness (i.e., have a clear sense of one's self and one's goals) is associated with better outcomes in individuals with anorexia nervosa.115
ICD-9: 307.1 ICD-10 - Anorexia nervosa F50.0
An individual diagnosed with anorexia nervosa is extremely fearful of becoming fat and therefore restricts their total food intake, often so much that they consume only a few foods. Malnourishment caused by (semi-) starvation may result in muscle wasting, dehydration, abdominal pain, amenorrhea, constipation, cold intolerance, cardiac arrhythmias, impaired renal function, and osteoporosis. Lethargy and fatigue are common, also due to lack of food/energy intake; self esteem levels are low; depression, anxiety, and irritability are experienced. Cognitive deficits are also common with starvation. The individual may eventually become socially withdrawn and may experience somatic/sexual dysfunction, particularly in severely underweight individuals. Many individuals with anorexia nervosa are in denial of their illness; often medical attention is sought by concerned family members.7
Part 2 - Bulimia nervosa
Bulimia nervosa is an eating disorder characterized by cycles of binging and purging: the individual begins the cycle by eating large amounts of food in a single sitting, typically until the individual is uncomfortably full. The individual then tries to compensate for the overeating and tries to rid the body of the food that was consumed. There are two types of bulimia nervosa, depending on the method of compensation: purging type, in which the individual regularly engages in self-induced vomiting or the misuse of laxatives, diuretics, or enemas; or non-purging type, in which the individual uses other methods of compensation, such as fasting or excessive exercise, but does not regularly engage in self-induced vomiting or the use of laxatives, diuretics, or enemas.7- Self-induced vomiting is the most common method to compensate for binge eating, present in 80-90% of individuals who present for treatment,7 and therefore this section describes the health state of an individual with bulimia nervosa, purging type.
Bulimia nervosa predominantly affects females (about 90% of cases).7,116 Approximately one to three percent of young women develop bulimia nervosa in their lifetime.7,102 Bulimia nervosa typically begins in adolescence or early adulthood but can be difficult to identify because of extreme secrecy; in addition, most individuals with bulimia nervosa are within the normal weight range,7 so their eating disorder is not as obvious as if they were severely underweight (the disorder does occur in obese individuals but it is uncommon). The course of bulimia nervosa may be chronic or intermittent, with symptoms and remissions fluctuating over the years. Weight fluctuations are also common due to alternating binging and purging behaviours.
Bulimia nervosa is clinically diagnosed if the individual participates in recurrent episodes of binge eating; binge episodes are characterized by eating a larger amount of food than most people would eat in a specific amount of time and is accompanied by a lack of control over eating (i.e., can't stop eating) during this episode. In addition to the recurrent episodes of binge eating, the individual participates in inappropriate behaviour in order to prevent weight gain, such as self-induced vomiting or the misuse of laxatives. The binge eating and inappropriate behaviour must have occurred, on average, at least twice per week for three months and does not occur exclusively during episodes of anorexia nervosa. Finally, the individual's body shape and weight disproportionately influences their self-evaluation.7
Similar to anorexia nervosa, the causes of bulimia nervosa are not known. Cultural ideals and social attitudes toward body appearance are likely to contribute, as well as self-valuation based on body weight and shape. There is some evidence that obesity during adolescence or a genetic predisposition toward obesity contributes to the development of the disorder.117 Other factors that are associated with bulimia nervosa are a history of sexual or physical abuse, substance misuse, anxiety disorders, low self-esteem, perfectionism, parental weight/body shape concern and peer pressure. Binge eating is typically triggered by depressed mood, interpersonal stressors, hunger following dietary restraint, or feelings of self-depreciation. The individual binge eats to reduce these feelings but self-criticism and depression tend to follow. Suicide attempts are relatively common.107 Although preventive measures are not known at this time, early detection and interventions can reduce the severity of symptoms and improve prognosis.118,119
Treatment of bulimia nervosa usually involves a combination of individual therapy, family therapy, behaviour modification and nutritional rehabilitation. Cognitive-behavioural therapy focuses on self-monitoring of eating and purging behaviours and changing the thought pattern that leads the individual to binge and purge. Medication (i.e., antidepressants, antianxiety medication) may also be prescribed, particularly if the individual is experiencing depression or anxiety. If the bulimia nervosa is severe, the individual may have to be admitted to an eating disorders treatment program. Poor prognosis has been found to be associated with premorbid and paternal obesity, a history of substance misuse, and presence of a personality disorder.105,116
ICD-9: 307.51 ICD-10 - Bulimia nervosa F50.2
An individual with bulimia nervosa engages in binge eating behaviours and then attempts to compensate for the excessive food intake by purging. Individuals with bulimia nervosa are usually embarrassed about their eating problems and often feel out of control; therefore, they binge as inconspicuously as possible. The individual typically experiences anxiety, depression, and negative affect, using body weight and shape as the main measure of their self-worth. Self-esteem is low. The individual may have scars on the surface of their hand from contact with the teeth while pushing fingers down their throat to induce vomiting.7 Frequent, repeated purging may lead to increased dental cavities and loss of dental enamel (from the acid in the vomit), and potential fluid and electrolyte abnormalities may cause serious medical complications (rarely even death).7 Fatigue is common due to malnutrition and electrolyte imbalances. Irregular menstruation or amenorrhea may be present.120