CHAPTER 58
Eating Disorders
Michael Biglow, PharmD, BCPS, BCPP
Eating disorders are common conditions that warrant the attention of primary care providers. Eating patterns are aspects of self-care, and as such should be part of every physical and emotional assessment. Alterations in eating patterns may be symptomatic of multiple physical or psychiatric conditions or may be a specific disorder of eating. Primary care providers have the opportunity to monitor changes in eating patterns and discuss them fully with patients. Care in recording nutritional concerns will allow for early intervention into problems with eating.
Anorexia nervosa and bulimia nervosa are potentially life-threatening eating disorders that are very common, particularly in young women. Binge-eating disorder, which is briefly covered in this chapter, has also become more widely identifiable as a complicating factor in controlling patients’ other comorbidities. This chapter offers an overview of anorexia nervosa, bulimia nervosa, and binge-eating disorder, including diagnostic and treatment approaches.
ANATOMY, PHYSIOLOGY, AND PATHOLOGY
Anatomy and Physiology
The origins of eating disorders are not definitive; one line of research is in the area of neurobiology. The relations between eating disorders and mood disorders are being examined in terms of etiology based in the neuroendocrine or neurotransmitter systems. Neuroendocrine and metabolic abnormalities associated with anorexia nervosa may predate substantial weight loss, as evidenced by the development of amenorrhea before weight loss in one third of the women with anorexia nervosa. Serotonergic systems have been shown to play a role in appetite and satiety centers in the brain. Elevations in serotonin metabolites have been noted in anorexic patients and remain altered after normal weight has been achieved (Bailer & Kaye, 2011; Miller, 2011).
The more severe complications of eating disorders are secondary to starvation or purging; these complications are not the underlying pathology. Complications become severe once adipose tissue reserves are depleted and there is more severe food refusal. At this point protein catabolism increases and water loss is accelerated, with metabolic and electrolyte disturbances. Other complications arise from vomiting or the use of laxatives or diuretics for purging.
Psychopathology
The etiology of both anorexia nervosa and bulimia nervosa is multifactorial and is associated with psychological determinants (Bruch, 1973). Classic explanation of anorexia nervosa characterizes children of overly involved mothers with poorly developed identities and a sense of ineffectiveness. Other models expand on Bruch’s psychoanalytic approach to encompass additional individual, family, and cultural factors. Individual factors include emotional instability, anxiety (possibly social phobia or obsessive–compulsive symptoms), and personality disorders. Other factors associated with the development of an eating disorder include: a history of dieting, a childhood preoccupation with thinness, and participation in athletic or artistic activities that emphasize weight and leanness or are subjective in scoring (e.g., ballet, wrestling, gymnastics; McKnight Investigators, 2003).
Depression and anxiety are common comorbidities associated with eating disorders. It may predate the eating disorder symptoms or may be secondary to starvation, often improving with weight gain. Patients with anorexia nervosa typically have distortions in thinking and reasoning, with an extreme focus on their weight and eating behavior. Their sense of self-esteem is tied to their perception of being thin. Neuroendocrine and metabolic abnormalities associated with anorexia nervosa are related to starvation and have also been viewed as a potentially predisposing factor (Kaye, 2008).
Anorexia nervosa is frequently precipitated by dieting after either a perception of being plump or a comment by someone else. Depression and stressful experiences typically associated with greater autonomy (e.g., puberty, parental divorce, graduating from high school, beginning college, leaving home) are all potential precipitating factors for anorexia nervosa. The patient has a sense of control of food in the face of feeling out of control in other areas. The effects of starvation provide perpetuating factors in anorexia nervosa (Kaye, 2008).
Patients with bulimia nervosa typically come from families where there is parent–child conflict, sometimes with physical, verbal, or sexual abuse. Patients feel guilty and out of control after bingeing, and they purge to relieve this tension. They have marked fluctuations of weight but not the extremely low weights seen in anorexia nervosa. Binge-eating behavior or the sensation of loss of control during eating, commonly seen in binge-eating disorder, could be prodromal for bulimia nervosa (American Psychiatric Association [APA], 2013).
EPIDEMIOLOGY
Eating disorders, in general, are more common in women than men with a male to female ratio ranging from 1:6 to 1:10 (Hoek & vanHoeken, 2003). Anorexia nervosa has a lifetime prevalence of 0.3% to 3.7% in women. Bulimia nervosa is also more common among young women, with a prevalence of 1% to 4.2%; men account for 10% of patients with the disorder (Hoek & vanHoeken, 2003). Previously, the category of eating disorder not otherwise specified was the most common diagnosis with a prevalence of 3% to 5% but with the expansion of eating disorder classifications in the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5) the proportion is expected to be reduced (Smink, van Hoeken, & Hoek, 2013).
DIAGNOSTIC CRITERIA
Diagnostic Criteria for ANOREXIA NERVOSA
Caloric restriction that does not meet the needed requirements to maintain a body weight appropriate for age, sex, development, and overall health.
Fear of weight gain or being perceived as fat as well as regular patterns of behavior that prevent normal weight gain.
Inability to recognize the detrimental effect of the severe weight loss on one’s health or distortion of one’s perception of a normal or desirable weight.
Source: Adapted from the DSM-5, American Psychiatric Association (2013).
There are two types of anorexia nervosa: the restricting type, in which the patient does not regularly binge or purge, and the binge-eating or purging type, where there is regular binge-eating or purging. Severity is also a key feature in the diagnosis and is reported as a function of body mass index (BMI) but needs to be in context of the patient’s condition. Severity levels range from mild (BMI ≥17 kg/m2), moderate (BMI = 16–16.99 kg/m2), and severe (BMI = 15–15.99 kg/m2), to extreme (BMI <15 kg/m2; APA, 2013).
The seriousness of the low weight is often denied. Restrictive behaviors common in dieting are used to a much greater extreme and with an inability to stop. Some patients also use more dangerous methods such as self-induced vomiting or large doses of laxatives, or they misuse diuretics and appetite suppressants. Other symptoms are those common to semi-starvation, including depressed mood, irritability, social withdrawal, loss of libido, preoccupation with food, obsessional behavior, reduced alertness, and poor concentration (APA, 2006).
Diagnostic Criteria for BULIMIA NERVOSA
Repeated episodes of binge eating, which can be described as eating an abnormally large amount of food in a specific range of time, usually <2 hours, with the patient describing a loss of control or inability to stop while eating.
Patient takes inappropriate measures to avoid weight gain, such as:
Self-induced vomiting
Abuse of medications (laxative, diuretics, stimulants, etc.)
Fasting
Excessive exercise
The pattern of binge-eating with the inappropriate measures occurs at least once a week for 3 months.
The patient is overly concerned about body shape and weight.
The patient does not have a diagnosis of active anorexia nervosa.
Source: Adapted from the DSM-5, American Psychiatric Association (2013).
Severity of bulimia nervosa is gauged by the average number of episodes of inappropriate behaviors (listed previously) per week. Severity ranges from mild bulimia (1–3 episodes/wk), moderate (4–7 episodes/wk), severe (8–13 episodes/wk), to extreme (>14 episodes/wk; American Psychiatric Association (APA), 2013). It is common for patients to progress from anorexia nervosa to bulimia nervosa, and some alternate between the two illnesses.
Other newly defined eating disorders in the DSM-V include:
Binge-eating disorder—repeated episodes of overeating in a discrete amount of time with a sense of loss of control.
Pica—a disorder described as persistent eating of non-nutritive or nonfood substances (e.g., paper, cloth, soil, metal).
Avoidant/restrictive food intake disorder—reduced nutritional intake due to either lack of interest, averse reaction to food sensory characteristics, or concern regarding the consequences of eating.
The severity of these newer eating disorders can range from simple weight changes to severe medical complications. As of yet, there is no consensus on treatment of the other newer disorders and the approach should be based upon the severity of the condition and the practitioner’s clinical judgment (APA, 2006).
Binge-Eating Disorder
Binge-eating disorder, which has been proposed as an eating disorder since the 1990s, is addressed in the most recent edition of the American Psychiatric Association Practice Guidelines for the Treatment of Eating Disorders, published in 2006, with the focus on weight management and binge-eating reduction. It is defined in the DSM-5 as recurrent episodes of eating larger amounts of food that would be considered normal as well as feeling a lack of control while eating during the episode. The patient generally eats faster than normal, eats until overly full, eats when not physically hungry, eats alone due to embarrassment, and/or feels ashamed or guilty after a binge-eating episode (APA, 2013).
Binge eating is generally more prevalent than anorexia or bulimia nervosa with a lifetime prevalence of 1.9% with a higher rate of females who meet the criteria (Kessler et al., 2013). While the pathology behind binge-eating disorder is not well understood, the complications associated with it are generally similar to those associated with obesity (i.e., diabetes, cardiovascular complications, hypercholesterolemia). A recent study noted that patients with binge-eating disorder had significantly higher rates of hypercholesterolemia (30% vs. 17%) compared to similar-sized patients with no eating disorder (Hudson et al., 2010). Patients with binge-eating disorder generally have greater functional impairment, lower quality of life, and higher rates of psychiatric comorbidities when compared to weight-matched obese patients (APA, 2013).
Antiepileptics and antidepressants have been studied in reducing the binge-eating behavior but first-line therapy remains psychotherapy; and appetite or anti-obesity medications are not recommended due to lack of efficacy or potentially severe adverse effects (APA, 2006; Grilo, Masheb, & Salant, 2005; James et al., 2010).
HISTORY AND PHYSICAL EXAMINATION
A careful history and physical examination provide information for the differential diagnosis and raise suspicion of an eating disorder. A careful and detailed eating history is crucial. Detailed questionnaires, such as the SCOFF screening, have high sensitivity and selectivity in identifying patients with anorexia nervosa and bulimia nervosa (Morgan, Reid, & Lacey, 1999).
SCOFF Questionnaire
Do you make yourself Sick because you feel uncomfortably full?
Do you worry you have lost Control over how much you eat?
Have you recently lost more than One stone (14 lbs) in a 3-month period?
Do you believe yourself to be Fat when others say you are too thin?
Would you say that Food dominates your life?
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