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Introduction
Eating Disorders as Mutidetermined
Diagnostic Groups
Anorexia Nervosa
Bulimia Nervosa
Eating Disorders Not Otherwise Specified
Relationship Between Different Eating Disorders
Eating Disorders as Multi-determined
Introduction
Eating disorders have been described in the psychiatric literature for many years; however, it has only been in the past two decades that they have commanded widespread interest in mainstream psychology, psychiatry, and allied professions (Theander, 2004). One reason for this interest is recognition of their significant health consequences. Anorexia nervosa is estimated to be the third most common chronic medical illness in girls aged 15-19 years old (Lucas, Beard, O.Fallon, & Kurklan, 1991). It is associated with significant medical complications (Becker, Grinspoon, Klibanski, & Herzog, 1999; Sharp & Freeman, 1993) and mortality rates exceed the expected incidence of death from all causes among women 15-24 years of age by 12-fold (Sullivan, 1995). Mortality rates for bulimia nervosa are much lower but still not insignificant (Keel, Dorer, Eddy, Franko, Charatan, & Herzog, 2003; Nielsen, 2003). Moreover, eating disorders during adolescence are associated with elevated risk for a broad range of physical and mental health problems during early adulthood.
Eating Disorders as Mutidetermined
Another reason responsible for the growing attention to eating disorders is that they provide a model of the complex interaction between cultural, somatic, and psychological factors in abnormal functioning. The varied psychological features associated with eating disorders contribute to their heterogeneity on presentation. Finally, there are potentially serious physical and psychological consequences of starvation that must be addressed in the understanding and the treatment of the eating disorders. These factors, as well as the increasing prevalence of eating disorders among adolescent and young adult women, have led to a rapid increase of research on eating disorders and their treatment. The last two decades have led to divergence in etiological formulations as well as convergence of opinion regarding the utility of certain practical intervention principles (Garner & Garfinkel, 1997). In spite of these advancements, current knowledge has yet to yield conclusive support for any one theoretical viewpoint or treatment modality.
Diagnostic Groups
The prevailing diagnostic systems, namely the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV-TR; American Psychiatric Association [APA], 2000) and the International Classification of Diseases, 10th revision (World Health Organization [WHO], 1992), formally define as well as distinguish the two major eating disorders, anorexia nervosa and bulimia nervosa. By drawing the boundaries for these eating disorders, the current DSM-IV-TR diagnostic criteria have substantial implications for clinical care and research.
Eating Disorders: An Overview© is adapted and summarized from material published previously. For References and complete text, see publications # 143, 144, 148, 149, 165, 169 and IX. Also, consult the Eating Disorders Topics tab for more information on eating disorders.
Anorexia Nervosa
The requirements for diagnosis of anorexia nervosa according to the DSM-IV-TR (2000) are summarized as follows: 1.) Refusal to maintain a body weight over a minimally normal weight for age and height (e.g., weight loss leading to maintenance of a body weight less than 85% of that expected or failure to make expected weight gain during a period of growth). 2.) Intense fear of gaining weight or becoming fat, even though underweight. 3.) Disturbance in the way that body weight, size, or shape is experienced. 4.) Amenorrhea in females (absence of at least three consecutive menstrual cycles).
The DSM-IV-TR (APA, 2000) divides anorexia nervosa into two diagnostic subtypes: 1) restricting type and 2) binge eating/purging type. The restricting type is defined by rigid restriction of food intake without bingeing or purging, while the binge eating/purging type is defined by stringent attempts to limit intake, followed by episodes of binge eating as well as self-induced vomiting and/or laxative abuse. This definition differs from earlier descriptions of anorexia, in which the disorder was simply subdivided based on the presence or absence of binge eating. Patients who regularly engage in bulimic episodes report greater impulsivity, social/sexual dysfunction, substance abuse, general impulse control problems, family dysfunction, and depression as part of a general picture of more obvious emotional disturbance than patients with the restricting subtype of anorexia nervosa. Those with the restricting type of anorexia nervosa are often characterized as overly compliant, but also obstinate, perfectionistic, obsessive-compulsive, shy, introverted, interpersonally sensitive and, stoical.
Bulimia Nervosa
The criteria for the diagnosis of bulimia nervosa according to the DSM-IV-TR (APA, 2000) are summarized as follows: 1.) Recurrent episodes of binge eating (a sense of lack of control over eating a large amount of food in a discrete period of time). 2.) Recurrent inappropriate compensatory behavior in order to prevent weight gain (i.e., vomiting, abuse of laxative, diuretics or other medications, fasting or excessive exercise). 3.) A minimum average of two episodes of binge eating and inappropriate compensatory behaviors per week for the past three months. 4.) Self-evaluation unduly influenced by body shape and weight. 5.) The disturbance does not occur exclusively during episodes of anorexia nervosa. Bulimia nervosa patients are further subdivided into purging and non-purging types based on the regular use of self-induced vomiting, laxatives or diuretic (APA, 2000).
Eating Disorders Not Otherwise Specified (EDNOS)
The DSM-IV-TR (APA, 2000) delineates a large and diverse diagnostic category, "Eating Disorder, Not Otherwise Specified” (EDNOS), for individuals with clinically significant eating disorders who do not meet all of the diagnostic criteria for anorexia nervosa or bulimia nervosa. Unfortunately, the term "not otherwise specified" could be interpreted as meaning that these eating problems have minor clinical significance. This assumption is incorrect since the clinical picture for many individuals with EDNOS can be every bit as complicated and serious as the two main eating disorders. For example, in order to qualify for this diagnosis, binge eating must occur, on average, at least twice a week for a six month period. This means that patient who is normal weight and who does not engage in objective binge-eating episodes but vomits 20 times following subjective binges (small amounts of food), would be classified as EDNOS rather than bulimia nervosa. Many patients complain that having a diagnosis of “not otherwise specified” discounts their level of suffering and makes them feel like they do not have a “real” problem.
Relationship between Different Eating Disorders
Current systems of diagnosing the two main eating disorders into mutually exclusive categories, based largely on body weight, present some limitations. This distinction overlooks the overlap between these eating disorders. Bulimia and anorexia nervosa can have virtually identical cognitive, clinical, psychological and behavioral symptoms. Binge eating is the hallmark for bulimia nervosa; however, it is also a common symptom in anorexia nervosa. The major difference between the disorders is that in anorexia nervosa (binge eating/ purging subtype), these symptoms occur at a low body weight. Nevertheless, the body weight threshold used to define anorexia nervosa is arbitrary. Some patients move between the diagnostic categories of anorexia and bulimia nervosa at different points in time based only on variations in body weight; thus, it is counterintuitive to suggest that these diagnostic entities are not shared to some extent. Moreover, the extraordinary variety within each of the anorexia and bulimia nervosa diagnostic subclasses emphasizes the need to be careful about generalizations based only upon diagnosis. Body weight is not likely to be the ideal marker for differentiating between eating disorders (Garner, Garner and Rosen, 1993).
Extraordinary variability exists within each of the diagnostic subgroups, in terms of demographic, clinical, and psychological variables. People with anorexia and bulimia nervosa can move between the diagnostic categories at different points in time. For example, some patients may alternate between the two subtypes of anorexia nervosa (restricting and binge eating/purging types). However, it is more common for restricters to move toward bulimia (and purging) than for bulimic patients to move to an exclusively abstaining mode. Some women move back and forth between the two subclasses for years.
Although distinctions between diagnostic subgroups have been emphasized in research, recognizing that the different subclasses share numerous features is important. For example, even though persons with anorexia are differentiated into "restricter" and “binge eating /purging" subtypes, virtually all eating disorder patients "restrict their food intake", "diet" and probably "fast" for abnormally long periods of time. Some do this in association with binge eating, some with vomiting, and/or purging, and others with neither of these symptoms. For some persons, these symptoms occur at a statistically "normal" body weight (bulimia nervosa) and for others it occurs well over the body weight norms (e.g. binge-eating disorder).
The “classic” case of anorexia nervosa has historically been known for the restricting eating pattern rather than for binge eating and some have emphasized the relative similarity of this “restricting anorexia nervosa” (RAN) subgroup. The RAN subgroup has been described as perfectionistic, obsessional, inflexible, socially introverted, emotionally reserved, conflict avoidant, rule-minded and overly compliant. The RAN subgroup also has been distinguished from individuals with more temperamental personalities who have the “typical” bulimic symptom pattern. These people are generally characterized as having greater impulsivity, interpersonal conflict, and mood instability, regardless of whether they are at normal body weight in bulimia nervosa or as a suboptimal weight in anorexia (binge-eating/purging subtype). However, as mentioned earlier, inferring specific psychological traits from the behavioral symptoms of an eating disorder is overly simplistic and does little to explain meaningful distinctions between patient subgroups (Garner et al., 1993).
Eating Disorders as Multi-determined
During the past several decades, the idea that eating disorders are caused by a single factor has been replaced by the view that eating disorders are "multi-determined". More than 25 years ago, Garner & Garfinkel (1980) proposed a model in which symptom patterns represent final common pathways resulting from the interplay of three broad classes of predisposing factors shown in Figure 1. Accordingly, environmental, cultural, individual (psychological and biological) and familial causal factors combine with each other in different ways leading to the development of eating disorders.
Cumulative evidence in recent years has specified in greater detail the respective roles of cultural, individual (developmental, psychological, biological, and genetic) and familial risk factors that contribute to the expression of eating disorders (Jacobi, Hayward, de Zwaan, Kraemer, & Agras, 2004; Stice, 2002). Important predisposing factors include (a) female gender; (b) living in Western society; (c) adolescence and early adulthood; (d) low self-esteem; (e) perfectionism; (f) depression; and a family history of any type of eating disorder, obesity, depression, or substance abuse. Significant precipitating factors include: (a) dieting to lose weight; (b) occupational or recreational pressures to be slim; (c) critical comments about weight and shape; and (d) sexual abuse. Key perpetuating factors are the psychological, emotional, and physical effects of starvation. Many risk factors do not fit into a simple paradigm as a predisposing, precipitating, or perpetuating factor and the precise mechanism of action for many known risks remains elusive. The period of vulnerability for certain risk factors is fixed because of their nature (e.g., gender or birth complications) whereas others may exert their influence at multiple points in the development and maintenance of the disorder (e.g., family dieting or a genetic liability for perfectionism). Although the strength of evidence for different risk factors varies considerably, the variables that have received the most research interest in recent years are listed below.
Table 1: List of Risk Factors with Some Research Support
Table 1: List of Risk Factors with Some Research Support
SOCIO-CULTURAL
Living in Western Society
Sports Emphasizing Slimness
INDIVIDUAL / PSYCHOLOGICAL
Female Gender
Ethnicity
Adolescence
Higher Premorbid Weight
Pubertal Status and Timing
Restrictive Dieting
High Levels of Exercise
Alcohol / Drug Abuse
Drive for Thinness
Body Dissatisfaction & Weight Concerns
Body Misperception
Low Self-Esteem or Ineffectiveness
Depression
Perfectionism
Asceticism / Self-Sacrifice
Obsessive Compulsive Traits
Anxiety / Worry
Interpersonal Insecurity / Alienation / Attachment Deficits
Fears of Psychobiological Maturity
Harm-Avoidant Temperament /
Low Interoceptive Awareness
Emotional Regulation Problems (over or under-control)
Anger
Reasoning Errors Information Processing /
Attentional Bias
Neuropsychological Deficits
GENETIC FACTORS
INDIVIDUAL DEVELOPMENTAL
Early Childhood Feeding Problems
Pregnancy Complications / Premature birth
Childhood Anxiety Problems
Childhood Obesity
Early Puberty
Age: Adolescence
ADVERSE LIFE EVENTS
Physical Abuse or Neglect
Sexual Abuse
Bullying and Teasing
Physical Illness
Weight Loss in Adolescence
PARENTAL RISK FACTORS
Obesity
Dieting
Mother with an Eating Disorder
Critical Comments about Weight
High Levels of Exercise
High Performance Expectations
Over-Concern / Hypervigilance
Depression
Low Contact / Neglect / Conflict
Substance Misuse
Based on summary data from: Jacobi, Hayward, de Zwaan, Kraemer, & Agras, 2004; Stice, 2002; Fairburn, & Harrison 2003; Ricciardelli & McCabe (2004).
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