Eating disorders

Eating disorders are driven behavioral disorders resulting in significant functional impairment and, in extreme cases, death.

Three major categories of eating disorders: anorexia nervosa (AN), bulimia nervosa (BN), and eating disorder not otherwise specified (EDNOS).

Binge-eating disorder (BED) is usually accompanied by obesity and is subsumed under the EDNOS category. BED is currently under consideration as a distinct eating disorder in DSM-V and has become the focus of significant clinical and scientific attention.

Unlike BED, AN and BN are perhaps better thought of as “dieting disorders”. Both are characterized by an overvalued fear of fatness that drives a set of disturbed behaviors, including restricting food intake, binge eating, excessive exercise, self-induced vomiting, and abuse of laxatives, diuretics, and diet pills. Engagement in these behaviors, coupled with the physiologic consequences of starvation and/or the binge-purge-restrict cycle, sustains and heightens food preoccupation and body image disturbance.

BN is a dieting disorder characterized by episodes of binge eating followed by compensatory behaviors aimed at preventing weight gain. Binge eating is defined as consumption of an amount of food definitely larger than most people would eat in a similar period, under similar circumstances, and is associated with a sense of loss of control over eating. Typical binge foods are high-fat, high- calorie, “forbidden” foods, and amounts consumed are 1000 to 2000 calories or more per binge. Between binges, bulimic individuals typically restrict intake and only consume “safe,” low-calorie, low-fat foods. Other compensatory behaviors following a binge can include purging, vomiting, abuse of laxatives or diuretics, or excessive exercise. As in AN, dieting and preoccupation with thinness develop into a consuming passion that is difficult to interrupt and impairs psychologic and social function. The distinction between AN-P and BN is primarily one of weight. Individuals who binge and purge but are less than 85% of ideal body weight or a body mass index (BMI) of about 17.5 and are amenorrheic are given the diagnosis of AN-P, whereas those who are less underweight, or are normal weight or overweight, are given the diagnosis of BN. The two subtypes of BN are purging (BN-P) and nonpurging (BN-NP). Individuals with BN-NP do not self-induce vomiting or abuse laxatives or diuretics; rather, they alternate episodes of binge eating with fasting or excessive  exercise to avoid weight gain.

Eating Disorder Not Otherwise Specified (EDNOS) is a heterogeneous diagnostic category. It includes partial-syndrome cases of AN and BN, BED, and atypical eating disorders. For partial-syndrome AN or BN, the diagnosis of EDNOS does not imply minor clinical significance. Indeed, these cases may be associated with morbidity equal to or greater than full-syndrome cases of AN or BN. An example would be an individual whose baseline weight was obese and who developed intense fear of fatness and extreme dieting behaviors, rapidly losing more than 40% of his or her body weight yet failing to meet the underweight criterion for AN or the binge frequency criterion for BN.

BED is defined as regular binge eating, twice a week or more, associated with a subjective sense of loss of control over eating but lacking the compensatory behaviors typical of BN. BED differs from BN in several additional ways. Individuals with BN restrict their food choices and calorie intake when not bingeing yet often are more impulsive and consume more calories during binges than do individuals with BED. Patients with BED overeat more consistently throughout the day than do patients with BN and are more likely to be overweight or obese.

Examples of atypical eating disorders include globus hystericus, or fear of swallowing, resulting in severe weight loss and functional impairment, and psychogenic vomiting syndromes. In some cases, these may be factitious disorders, conditions in which the behavior persists in part because the sick role has become rewarding to the affected individual.

Research has identified several personality traits associated with eating disorders including elevated harm avoidance, neurotic personality features, and low self-esteem. Perfectionism, conscientiousness, persistence, and obsessive qualities are often discriminating features of AN, whereas elevated impulsivity, novelty seeking, negative emotionality, stress reactivity, and personality traits associated with antisocial, borderline, histrionic, and narcissistic personality disorders are more commonly associated with BN.

Eating disorders are significantly more prevalent in menstruating girls and women than in prepubertal girls, a finding implicating a role for ovarian hormones and sexual development in the activation of disordered eating. Perception of being overweight prepubertally and early-onset menarche have emerged as specific aspects of puberty that may increase eating disorder vulnerability. Early-maturing girls have higher adiposity before menarche, are more dissatisfied with their bodies, and are more likely to engage in weight-loss efforts than girls who go through puberty on time or later in life. Environmental changes associated with the transition to college, including high levels of stress, performance and achievement demands, and role and identity changes, are factors significantly related to disordered eating and may make this developmental milestone one that places late adolescents at risk of developing eating disorders. Past trauma, namely, childhood sexual abuse, may heighten the risk of developing eating disorders; however, early sexual abuse has been associated with other psychiatric conditions, thus making it difficult to determine whether a direct link between eating disorders and childhood sexual abuse exists or whether early sexual abuse and mental health are more broadly linked.

Slender female models and images (e.g., cartoons, computer graphics) saturate the Western mass media. Internalization, or acceptance, of these societal standards of thinness may lead to low self-esteem, negative affect, dieting, and/or eating disorders in girls and women. Experimental studies have consistently shown that girls and women exposed to media images of thinness experience greater body dissatisfaction in comparison with those exposed to heavier or neutral images. The negative effect of these images is heightened when girls and women viewing slender images have already internalized thin beauty ideals or have high baseline levels of body image disturbance.

Parents are the most dominant sociocultural factor affecting young children, and parents’ direct comments about their child’s weight, particularly comments of mothers, have been identified as the most consistent factor associated with children’s concerns and behaviors related to weight and shape. Familial dynamics are also important predisposing factors in eating disorders. Girls who eat alone, who have parents who are not married, or who perceive their family communication, parental caring, and parental expectations as low are at increased risk of disordered eating.

Eating is a highly social activity, and eating disorders inevitably impair interpersonal function. Affected individuals become socially isolated in an attempt to hide or avoid confrontation regarding their food choices or amounts eaten and spend increasing time engaged in eating rituals and exercise routines that take precedence over ageappropriate social engagements. Formation of intimate relationships and sexual function are often impaired by starvation’s effect on libido and heightened body image concerns. Because they primarily affect young women and girls, AN and BN often result in the interruption of normal developmental tasks including separation- individuation from parents, identity formation, and the development of meaningful peer relationships.

Individuals with eating disorders describe a consuming and constant preoccupation with food and weight that occupies much of their waking time and worsens with starvation. Furthermore, starvation results in a syndrome characterized by low mood, apathy, anhedonia, and decreased concentration and energy that is indistinguishable from major depression but reverses within days or weeks of refeeding. Besides starvation-related increases in obsessional preoccupation with food and weight and depressive symptoms, family studies have confirmed increased rates of affective disorders, alcohol abuse, and anxiety disorders in first-degree relatives of individuals with AN and BN. This finding suggests that comorbid psychiatric conditions are common and may complicate the treatment course unless they are addressed in parallel with the eating disorder. Finally, demoralization and loss of self-esteem often accompany patients’ attempts to control their behaviors and the realization that these behaviors have impaired their functioning.

Malnutrition and starvation in AN are associated with numerous physical signs and symptoms. Patients often appear emaciated, with muscle wasting and weakness on examination, and may develop lanugo, the growth of fine, diffuse body hair. Physiologic responses to selfstarvation are aimed at conserving energy and include bradycardia, hypotension, hypothermia, and interruption of the hypothalamic-pituitary-ovarian axis. Estrogen, follicle-stimulating hormone, and luteinizing hormone revert to prepubertal levels, as a result of disturbances in gonadotropin-releasing hormone pulsatility, resulting in amenorrhea and infertility. In prepubertal patients, normal secondary sexual characteristics, such as breast development and height, may be halted by malnutrition.  Patients frequently complain of cold intolerance, fatigue, and gastrointestinal symptoms, including bloating, early satiety, and constipation. Starvation also results in delayed gastric emptying, delayed gastrointestinal transit times, and constipation. Anemia is common, and pancytopenia and bone marrow suppression can occur in severely malnourished patients. Osteoporosis is a largely irreversible consequence of AN, occurring relatively early in the course of the disorder; most affected girls and women develop significant decreases in bone density within a year of onset, and osteoporosis  also can be a complication for boys and men with AN.

Osteoporosis results in elevated fracture risk, and patients with chronic AN are at risk of debilitating hip fractures and spinal compression fractures. Finally, hypoglycemia is common in starvation; and depleted glycogen stores in AN complicate serum glucose regulation. Chronic hypoglycemia also may underlie some of the neuroendocrine disruptions observed in this condition. Disturbances in glucose counter regulatory hormones in AN include alterations in growth hormone, cortisol, and catecholamines. These changes may in turn contribute to the maintenance of anorectic behaviors and cognitions.

AN and BN are behavioral disorders and, like addictions, once established, tend to take on a life of their own. Although certain stressors and risk factors are associated with their onset, disordered eating patterns eventually sustain themselves. Initial treatment goals include normalizing eating patterns and restoring weight in underweight patients by using behavioral psychotherapeutic interventions. Starvation perpetuates a preoccupation with food, and weight restoration is well established as necessary, if not sufficient, for recovery from AN. Similarly, in BN, repeated engagement in the restrict-binge-purge cycle exacerbates symptomatic preoccupations with weight and shape and the drive to diet. Psychotherapy aimed at elucidating underlying individual vulnerabilities to these disorders may provide a meaningful narrative to patients to help them understand the development of their disorder, but it is unlikely to bring about behavioral change.

Patients with AN or BN tend to be ambivalent about treatment because they experience their dieting behaviors as rewarding and do not want to stop them. Successful treatment can be seen as requiring a cognitive shift or conversion, from viewing dieting as a solution to seeing it as the primary impairment to healthy function.

In the case of both AN and BN, education about normal eating should include instruction on scheduling three regular meals a day, eating normal portion sizes, expanding food repertoire (which is often very narrow), and avoiding diet foods. Patients should be encouraged to consume all foods in moderation and in normal combinations and to avoid fat-free or sugar-free diet products. An exception to the latter may be the case for patients with BED or BN who are overweight. These patients are likely to benefit from additional guidance on eating fewer high-calorie, high-fat foods; introducing more fruits, vegetables, and whole-grain unprocessed foods; increasing the water density of foods consumed; and engaging in a regular exercise program as well as decreasing sedentary activities, such as watching television. Vegetarianism that develops after the onset of dieting behavior is common in both AN and BN and should be discouraged because it is often used to disguise dieting. Careful questioning usually reveals that preferred vegetarian foods are limited to those low in calories.

Persistent encouragement, persuasion, and guidance to change dietary patterns usually are necessary to achieve behavior change in this population. Gastrointestinal symptoms and complaints of nausea, heartburn, abdominal pain, gas, and constipation are common during the early stages of refeeding.

AN is characterized by refusal to eat rather than by inability to eat or a nonfunctional gastrointestinal tract. Therefore, oral feeding is the safest method of weight restoration from both a physiologic standpoint and because this disorder is marked by narrowing of the food repertoire  and conditioned avoidance of high-calorie density foods.

Although significant changes in body weight are commonly associated with eating disorders, it is not uncommon for individuals who are clinically depressed to lose or gain weight. Major depression is characterized by depressed mood and diminished interest in pleasurable activities accompanied by changes in sleep patterns, difficulty concentrating, loss of libido, lack of energy, feelings of worthlessness or guilt, thoughts of death or suicide, and a disturbance in appetite. Children who are depressed often present as irritable, instead of sad and tearful, and may fail to gain weight as expected.

In contrast to eating disorders, changes in appetite that occur during depressive episodes are not driven by fear of fatness and obsession with dieting and food. Rather, depressed individuals frequently report that they have lost interest in eating and tend to identify their weight loss as a problem. These individuals are less likely to become distressed over the thought or reality of resuming normal eating and may even express a desire to do so. Furthermore, their eating pattern does not reflect the restriction of fats, sweets, and high-calorie foods that is typical of AN. Rather, they just eat less and describe losing a taste for food. Eating patterns in this population also may reflect decreased consumption of fish, fruits, and vegetables possibly because of decreased motivation to cook or prepare foods.

Schizophrenia is a psychotic disorder often characterized by delusions, hallucinations, disorganized speech and behaviors, and affective flattening. Individuals frequently become paranoid in response to delusional thoughts, which are erroneous, often bizarre, perceptions of reality that are strongly held, even in the presence of clear contradictory evidence. Although the content of delusions may include a variety of themes, they sometimes involve food or eating. An example of a delusion  involving food or eating includes a person’s belief that his or her food is contaminated or that he or she is being watched while eating. Such paranoid thinking often results in refusal to eat and, in turn, significant weight loss. Psychiatric management, which includes antipsychotic medication, supportive psychotherapy, and family-based interventions, is commonly recommended for individuals exhibiting delusional and other psychotic symptoms. Cessation of delusional thinking is often necessary for behaviors, such as eating and self-care, to improve.

Substance use disorders also can affect weight and eating. The effect of different substances on food intake varies depending on substance class and level of use. Substance dependence is characterized by tolerance, withdrawal, extensive and persistent use, functional impairment, and continued use in the presence of physical and psychologic consequences. Substance abuse lacks the tolerance and withdrawal that characterize substance dependence, but includes significant adverse and harmful substance–related consequences, such as legal problems or failure to meet social obligations. Substance intoxication is a more acute reversible psychologic and behavioral reaction to a substance and does not necessarily imply frequent and persistent use. Marijuana use is associated with increased appetite and food intake, and symptoms of cannabis withdrawal include increased irritability, depression, and decreased food intake. Alcoholism is associated with abnormal consummatory behaviors and susceptibility to overweight, obesity, and eating disorders. Patients with severe alcoholism may eat sporadically and obtain most of their caloric intake from alcohol, resulting in nutritional deficiencies, including risk of Wernicke-Korsakoff syndrome from inadequate thiamin intake. Whereas obesity is prevalent among individuals with a history of significant alcohol consumption, overweight is uncommon in the advanced stages of alcoholism, during which multiple, often irreversible, organ dysfunction is accompanied by severe illness, weight loss, and malnutrition. Cocaine and other amphetamines stimulate the central nervous system and usually decrease appetite and food intake, resulting in weight loss, which can be severe at times. Occasionally, individuals with an eating disorder may abuse these substances to lose weight.

Attention Deficit Hyperactivity Disorder - with a prevalence of 2% to 18%, attention deficit hyperactivity disorder (ADHD) is one of the most common psychiatric conditions seen in childhood. The cause of ADHD is presumed to be multifactorial, with contributions from both genes and environment. One environmental factor that may play a role in the onset or maintenance of ADHD is diet.

Increased consumption of processed food may worsen ADHD symptoms in some children not only because of the increased intake of food additives but also because of associated nutritional deficiencies associated with a Western diet high in processed foods. Several studies have found omega-3 deficiencies in children with ADHD.