Genetic Influences on Eating and the Eating Disorders

The current chapter reviews our progress in understanding how genes influence eating and eating disorders (EDs) by addressing the following areas: (1) how recognition of genetic influences on eating and EDs emerged; (2) the complex nature of genetic action; (3) what twin studies can tell us about genetic influences; and (4) the current state of linkage and association studies. It is concluded that genes are an important part of the explanatory framework for the etiology of EDs, with an important contribution of the shared environment to the development of cognition and attitudes that may initiate disordered eating practices, and a critical contribution of the environment in providing a context within which genetic risk is more likely to be expressed. We currently have a limited understanding of the specific genes that are implicated, and the ways in which genes and the environment work together to increase risk for disordered eating.

Epidemiology and Course of Eating Disorders

The epidemiology of eating disorders holds important clues for understanding factors that may contribute to their etiology. In addition, epidemiological findings speak to the public health significance of these deleterious syndromes. Information on course and outcome are important for clinicians to understand the prognosis associated with different disorders of eating and for treatment planning. This chapter reviews information on the epidemiology and course of anorexia nervosa, bulimia nervosa, and two forms of eating disorder not otherwise specified, binge eating disorder and purging disorder.

The Classification of Eating Disorders

The purpose of the chapter is to elucidate the key issues regarding the classification of eating disorders. To this end, a review of nosological research in the area of eating disorders is presented, with a particular focus on empirically based techniques such as taxometric and latent class analysis. This is followed by a section outlining areas of overlap between the current Diagnostic and Statistical Manual of Mental Disorders – Fourth Edition, Text Revision (DSM-IV-TR; American Psychiatric Association, 2000) eating disorder categories and their symptoms. Next, eating disorder classification models that are alternatives to the DSM-IV-TR are described and critically examined in light of available empirical data. Finally, areas of controversy and considerations for change in next version of the DSM (i.e., the applicability of DSM criteria to minority groups, children, males; the question of whether clinical categories should be differentiated from research categories) are discussed.

Evidence-Based Treatment for the Eating Disorders

This chapter comprises a focused review of the best available evidence for psychological and pharmacological treatments of choice for anorexia nervosa (AN), bulimia nervosa (BN), binge eating disorder (BED), and other specified and unspecified feeding and eating disorders (OSFED and UFED), discusses the role of primary care and online therapies, and presents treatment algorithms. In AN, although there is consensus on the need for specialist care that includes nutritional rehabilitation in addition to psychological therapy, no single approach has yet been found to offer a distinct advantage. In contrast, manualized cognitive behavior therapy (CBT) for BN has attained “first-line” treatment status with a stronger evidence base than other psychotherapies. Similarly, CBT has a good evidence base in treatment of BED and for BN, and BED has been successfully adapted into less intensive and non-specialist forms. Behavioral and pharmacological weight loss management in treatment of co-morbid obesity/overweight and BED may be helpful in the short term, but long-term maintenance of effects is unclear. Primary care practitioners are in a key role, both with regard to providing care and with coordination and initiation of specialist care. There is an emerging evidence base for online therapies in BN and BED where access to care is delayed or problematic.

Pharmacotherapy of the Eating Disorders

Many persons with eating disorders (EDs) receive pharmacotherapy, but pharmacotherapy research for EDs has lagged behind that for other major mental disorders. In this chapter, we first provide a brief rationale for using medications in the treatment of EDs. We then review the data supporting the effectiveness of specific medications or medication classes in treating patients with anorexia nervosa (AN), bulimia nervosa, binge eating disorder (BED), and other potentially important EDs, such as night eating syndrome (NES) and sleep-related eating disorder (SRED). We conclude by summarizing these data and suggesting future areas for research in the pharmacotherapy of EDs.

Interpersonal Psychotherapy for the Treatment of Eating Disorders

Interpersonal psychotherapy (IPT) is a focused, time-limited treatment that targets interpersonal problem(s) associated with the onset and/or maintenance of EDs. IPT is supported by substantial empirical evidence documenting the role of interpersonal factors in the onset and maintenance of EDs. IPT is a viable alternative to cognitive behavior therapy for the treatment of bulimia nervosa and binge eating disorder. The effectiveness of IPT for the treatment of anorexia nervosa requires further investigation. The utility of IPT for the prevention of obesity is currently being explored. Future research directions include enhancing the delivery of IPT for EDs, increasing the availability of IPT in routine clinical care settings, exploring IPT adolescent and parent–child adaptations, and developing IPT for the prevention of eating and weight-related problems that may promote full-syndrome EDs or obesity.

Medical Screening and Management of Eating Disorders in Adolescents

Eating disorders (EDs) in adolescents are serious illnesses that affect many aspects of their lives. The medical assessment includes a thorough history, physical exam, and targeted laboratory testing. EDs can cause serious medical complications in every organ system. Clinicians should be aware of medical conditions that may cause similar presenting symptoms and also be able to identify any medical complications that develop as consequence of the ED. Acute and long-term medical complications have been identified in adolescents with EDs. Medical management focuses on nutritional rehabilitation, weight restoration, and the prevention or reversal of medical complications. Treatment may occur in a variety of settings, but should be delivered by an interdisciplinary, experienced team and include the adolescent’s family.

Medical Comorbidities of Eating Disorders

Eating disorders are frequently characterized by medical complications that at times can be severe. Because of this, the medical assessment of patients with eating disorders is an important part of the evaluation process. Frequent complications include cardiovascular problems, including a decrement in heart rate variability that is a known risk factor for cardiac arrhythmias. Skeletal system changes, particularly the risk for osteoporosis and osteopenia, are common in patients with anorexia nervosa. Gastrointestinal complications can be quite prominent. In particular, there is a risk for gastric dilatation and gastric rupture in patients who binge eat. A variety of endocrine changes have also been described and there appears to be an association with eating disorders and poor control of diabetes mellitus.

Psychological Assessment of the Eating Disorders

The purpose of this chapter is to describe a process, based on a functional approach, that will help assessors to develop assessments for eating disorders and eating-related problems. This approach takes into account both theoretical and practical concerns, and allows assessors to individualize their assessments depending on their particular needs. This process starts with broad considerations about the context in which the assessment is to be given and ends with the choice of specific instruments to be used.

Proposed Syndromes and the Diagnostic and Statistical Manual V

The Diagnostic and Statistical Manual (DSM-IV-TR) of the American Psychiatric Association (2000) is currently being revised and new disorders are being considered for inclusion in DSM-V. In this chapter, we evaluate three proposed eating disorders for the DSM-V: binge eating disorder (BED), night eating syndrome (NES), and purging disorder (PD). The history and definition for each is reviewed, relevant theoretical models are presented and compared, and evidence for the usefulness of the models is described. Empirical studies of all three disorders show their independence from other disorders, although comorbid psychopathology is common. Psychological distress is also high, but evidence for negative impact on physical health is less pronounced. Finally, remaining questions for future research are summarized.