Abstract
In 1994, binge eating disorder (BED) was introduced as a disorder requiring further study in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV). It is now listed as a distinct eating disorder in the DSM-5, along with bulimia nervosa and anorexia nervosa. This article summarizes the information currently available on BED, so social workers will be knowledgeable as they work with clients with obesity, BED, and other eating disorders. Diagnostic criteria for BED are reviewed, as well as changes in the criteria since the diagnosis was first introduced. Prevalence estimates, available assessment instruments, and comorbidity are discussed. An overview of the systematic reviews and meta-analyses that have examined the treatment of clients meeting the criteria for BED is presented, and, finally, questions and issues that have been suggested for future research are offered.
Binge eating disorder (BED) is characterized by recurrent binge eating without behaviors, such as vomiting, use of diuretics or laxatives, or excessive exercise, to compensate for the intake of calories. BED is also associated with a loss of control and marked feelings of distress related to food intake. It has been estimated that between 0.7% and 4.0% of the general population suffers from BED (Latner & Clyne, 2008). BED is associated with comorbid psychiatric disorders, health problems, and obesity; and of those seeking treatment for obesity, it is estimated that 15–50% meet the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV; American Psychiatric Association, 1994) criteria for BED (Johnson, Spitzer, & Williams, 2001).
BED was introduced as a disorder requiring further study in the American Psychiatric Association’s (APA, 1994) DSM-IV. In this edition, BED was categorized as an eating disorder not otherwise specified (EDNOS). In the DSM-5 (American Psychiatric Association, 2013), BED is now listed as a distinct eating disorder, along with bulimia nervosa and anorexia nervosa. Researchers have been debating for several years whether or not BED should be categorized as its own separate eating disorder diagnosis. Hudson, Hiripi, Pope, and Kessler (2007) completed a large-scale survey and concluded that BED is more common than either bulimia nervosa or anorexia nervosa, and is at least as stable and chronic as either of these disorders. In addition, it exhibits significant comorbidity with other psychiatric disorders and is strongly associated with severe obesity (odds ratio = 4.9), a finding that was consistent with earlier research studies (de Zwaan, 2001; Hudson et al., 2006; Striegel-Moore & Franko, 2008). Based on these findings, Hudson et al. (2007) concluded that:
Collectively, these findings suggest that binge eating disorder represents a public health problem at least equal to that of the other two better-established eating disorders, adding support to the case for elevating binge eating disorder from a provisional entity to an official diagnosis in DSM-V. (p. 355)
The DSM-5 was released in May 2013 at American Psychiatric Association’s (2012) Annual Meeting in San Francisco. The Roman numeral designation (i.e., DSM-III, DSM-IV) has been eliminated to make future revisions easier to identify. The first revision of the DSM-5 will be denoted as the DSM-5.1. Since BED will now be a defined eating disorder, it is important that social workers be familiar with the diagnostic criteria and the current state of the research on the assessment and treatment of this disorder.
This article summarizes the information that is currently available on BED in the literature, so that social workers will be knowledgeable about the disorder as they work with clients with obesity, BED, and other eating disorders. First, the diagnostic criteria for BED are reviewed, as well as changes that have occurred in the criteria since the diagnosis was first introduced. Next, prevalence is examined, with particular emphasis on how the new diagnostic criteria may affect prevalence estimates. Assessment instruments that are used to assess and measure the severity of BED in clients are described, and the presence of comorbid mental disorders is discussed. An overview of the systematic reviews and meta-analyses that have examined the treatment of clients meeting the criteria for BED is presented, and, finally, questions and issues that have been suggested for future research are offered.
Diagnostic Criteria
There were two specific eating disorders defined in the DSM-IV: anorexia nervosa and bulimia nervosa. A diagnosis of EDNOS was reserved for individuals with significant eating disorder psychopathology who did not meet the diagnostic criteria for anorexia nervosa or bulimia nervosa. Anorexia nervosa was introduced in the DSM-III (American Psychiatric Association, 1980) and bulimia nervosa followed in the DSM-III–Revised (American Psychiatric Association, 1987). BED was introduced in the DSM-IV (APA, 1994) as a disorder requiring further study, and was listed as an example under the EDNOS diagnosis (Wilfley, Bishop, Wilson, & Agras, 2007).
The diagnostic criteria for BED as defined in the DSM-5 are shown in Table 1. There are two notable changes from the earlier criteria found in the DSM-IV–Text Revision (DSM-IV-TR; American Psychiatric Association, 2000). First, as stated earlier, BED is now listed as a separate eating disorder, along with bulimia nervosa and anorexia nervosa. Second, the required frequency and duration of binge eating behaviors for the diagnosis of BED have been reduced. In the DSM-IV-TR, binge eating had to occur, on average, at least 2 days a week for 6 months. In the DSM-5 criteria, binge eating has to occur, on average, at least once a week for 3 months. Another significant change to the BED diagnosis is the addition of a severity scale: Mild: 1–3 binge eating episodes a week; Moderate: 4–7 binge eating episodes per week; Severe: 8–13 binge eating episodes a week; and Extreme: 14 or more binge eating episodes per week. Anorexia nervosa has a severity scale based on the individual’s BMI, and the severity scale for bulimia nervosa is based on the number of weekly episodes of inappropriate compensatory behaviors.
DSM-5 Diagnostic Criteria for Binge Eating Disorder.
Fairburn and Cooper (2011) estimated that over 50% of clients diagnosed with an eating disorder using the DSM-IV criteria are diagnosed with the residual diagnosis of EDNOS. EDNOS is considered a residual diagnosis because it is used as a diagnosis for clients who have clinically significant eating disordered behaviors, but do not meet the individually defined eating disorder diagnoses. Tanofsky-Kraff et al. (2013) state:
Presently, the largest obstacle to optimal clinical utility of the DSM-IV is that a majority of individuals who seek treatment for an eating disorder do not meet diagnostic criteria for anorexia nervosa or bulimia nervosa. Rather, their clinical symptoms best fit a diagnosis of eating disorder not otherwise specified (EDNOS). (p. 195)
These issues have played a part in the current effort to reduce the frequency of the EDNOS diagnosis. Moving BED from EDNOS to its own diagnosis is expected to reduce the number of clients diagnosed with EDNOS. Two additional changes in the eating disorder diagnoses defined in the DSM-5 are expected to reduce the prevalence of EDNOS: (1) For a diagnosis of anorexia nervosa, amenorrhea is no longer required; and (2) for a diagnosis of bulimia nervosa, the frequency of binge eating and inappropriate compensatory behaviors has been reduced from at least twice a week for 3 months to at least once a week for 3 months (Keel, Brown, Holm-Denoma, & Bodell, 2011).
Validity and Reliability of the BED Diagnosis
The DSM-5 Task Force has completed the DSM-5 field trials and has reported the test–retest reliability of selected diagnoses included in the DSM-5. Tests were conducted to measure the degree to which two clinicians independently agree on the presence or absence of a DSM-5 diagnosis when the same client is interviewed on separate occasions. Regier et al. (2013) reported a κ value of .56 for BED, placing it in the category of “good agreement” (κ = .40 to .59) as defined by the APA.
As early as 1993, researchers have been analyzing the validity of the BED diagnosis. Spitzer et al. (1993) examined 1,785 individuals and concluded, “The validity of BED was supported by its strong association with (1) impairment in work and social functioning, (2) overconcern with body/shape and weight, (3) general psychopathology, (4) significant amount of time in adult life on diets, (5) a history of depression, alcohol/drug abuse, and treatment for emotional problems” (p. 137).
In an effort to determine whether BED should be classified as a separate eating disorder in the DSM-5, recent research has focused on the validity of the BED diagnosis. Latner and Clyne (2008) examined the differences in psychopathology between BED and bulimia nervosa and between BED and obesity without binge eating to determine the validity of the diagnosis of BED. While they found significant evidence to support differences in general psychopathology and eating-related psychopathology between individuals with BED and those with bulimia nervosa, they also found that both groups experience self-evaluation heavily based on weight and shape. These authors, therefore, suggest that overconcern with weight and shape should be considered as a diagnostic criterion for BED, as it is in bulimia nervosa. Latner and Clyne (2008) also found significant differences between obese individuals who meet the diagnostic criteria for BED and obese individuals that do not, with obese individuals with BED displaying greater general psychopathology, eating-related psychopathology, and body image disturbances. They conclude that the problems associated with BED seem to be more closely related to the presence of binge eating than to the presence of obesity, and disagree with the suggestion that obesity be included as a diagnostic criterion for BED.
In order to inform and influence the decision-making process for the status of BED in the DSM-5, Wonderlich, Gordon, Mitchell, Crosby, and Engel (2009) examined the validity and clinical utility of the BED diagnosis as defined in the DSM-IV. These researchers reviewed evidence to determine whether BED can be discriminated from the other eating disorders, anorexia nervosa and bulimia nervosa, as well as from obesity without BED. Using the guidelines for including or excluding categories in the DSM-5 established by Blashfield, Sprock, and Fuller (1990), Wonderlich et al. (2009) concluded that (1) there is reasonably strong evidence that BED differs from anorexia nervosa and bulimia nervosa on a number of different variables, such as age of onset, gender distribution, recovery rates, and psychiatric comorbidity; and (2) there is limited evidence that BED represents more than obesity with psychological disturbances. In addition, they suggested including overvaluation of shape and weight as a possible criterion in the BED diagnosis. Finally, they called for the need for additional research comparing obese clients with BED to obese clients without a BED diagnosis to further discriminate BED from simple obesity or obesity with nonspecific psychopathology.
Davis et al. (2008) compared 53 adults with BED, 59 normal weight adults, and 52 obese adults who did not report binge eating, in an effort to determine if individuals with BED differ in important ways from obese individuals who do not binge eat. Their conclusions differ from many other researchers that have examined this issue:
Our results suggest that from a psychological perspective, obese individual with and without BED do not seem to differ—a finding which casts some doubt on the appropriateness of BED as a distinct psychiatric disturbance. (p. 249) The data available from over a decade of research suggest that, based on these standards for establishing diagnostic validity, BED is as valid and clinically significant as the officially recognized eating disorders of anorexia nervosa and bulimia nervosa, and warrants inclusion as an officially recognized diagnosis. (p. 126)
Prevalence
Hudson et al. (2007), in a survey of 9,282 individuals, estimated a lifetime prevalence of DSM-IV anorexia nervosa, bulimia nervosa, and BED, respectively, at 0.9%, 1.5%, and 3.5% among women, and 0.3%, 0.5%, and 2.0% among men. Grucza, Przybeck, and Cloninger (2007) surveyed 910 individuals and found 6.6% met the DSM-IV criteria for BED with no significant difference between men and women. While various researchers (i.e., Croll, Neumark-Sztainer, Story, & Ireland, 2002; Fitzgibbon et al., 1998; Neumark-Sztainer et al., 2002; Smolak & Striegel-Moore, 2001; Story, French, Resnick, & Blum, 1995) have looked at disordered eating behaviors, including binge eating, among different ethnic groups, including Latino, Asian American, Caribbean, and African American, very little is known about the prevalence of BED among various ethnic populations (Striegel-Moore & Bulik, 2007). With the inclusion of BED into the DSM-5, it becomes even more important to look at the prevalence, risk factors, assessment and treatment issues, and the efficacy of various treatments for different populations.
Researchers have already begun looking at the extent to which the changes in the DSM-5 will affect the frequency of the EDNOS diagnosis, as well as how much the changes to the individual eating disorder classifications will affect the prevalence of the individual diagnoses. One of the current problems with the eating disorder diagnostic classification is that EDNOS, rather than being a residual diagnostic category as it was designed, is actually the most prevalent eating disorder (Fairburn et al., 2007). Since the changes for the DSM-5 were proposed, researchers have attempted to answer two questions: (1) How will the changes in the diagnostic criteria for BED affect the prevalence of BED? and (2) How will the changes in the definition for EDNOS affect the prevalence of EDNOS?
Hudson, Coit, Lalonde, and Pope (2012) attempted to answer the first question by studying 150 individuals diagnosed with BED and 150 individuals without any history of eating disorders to determine the percentage who would meet the diagnosis of BED in the DSM-IV versus the DSM-5. In a comparison of DSM-IV to DSM-5 prevalence rates, they found a 2.9% increase among women and a 3% increase among men for lifetime prevalence of BED, and a 7.7% increase in women and no increase for men for a current diagnosis of BED. The results of their study suggest that the use of the new DSM-5 criteria may have only a small effect on the prevalence of BED.
Trace et al. (2012) looked at 13,295 female twins to assess the impact of reducing the binge eating frequency and duration thresholds on the DSM-5 diagnostic criteria for BED. These researchers discovered that lifetime prevalence estimates of BED increased linearly as the frequency criterion was reduced. Changing the duration from 6 months to 3 months resulted in a slight increase in lifetime prevalence. They concluded:
This investigation offers empirical support for the proposed changes in the frequency and duration criteria for BN [bulimia nervosa] and BED in DSM-5 and provides evidence that this relaxing of criteria would allow for better detection of binge eating pathology while not leading to a markedly higher lifetime prevalence of illness nor consequent burdens on the health care system. (p. 536)
Keel, Brown, Holm-Denoma, and Bodell (2011) focused on the second question when they studied 397 individuals to determine the change in EDNOS diagnosis when using the proposed DSM-5 diagnostic criteria. Changing the diagnostic criteria from those found in the DSM-IV to the DSM-5 resulted in a 20% reduction of EDNOS cases. Based on the DSM-IV criteria, 14% of the participants had anorexia nervosa, 18% had bulimia nervosa, and 68% were diagnosed with EDNOS. When the DSM-5 criteria were used, 20% had anorexia nervosa, 18% had bulimia nervosa (unchanged), 8% had BED, and 53% were diagnosed with EDNOS. Therefore, over half of the reduction of EDNOS diagnoses was due to the inclusion of the BED diagnosis, although, despite the changes, EDNOS remained the most common eating disorder diagnosis. The conclusions of these researchers were that “findings support proposed revisions to eating disorders in the DSM-5 as successfully reducing reliance on EDNOS without significant loss of information” (p. 559). They also pointed to other proposals that have been made to identify other specific forms of EDNOS, such as purging disorder and night eating syndrome, which could further reduce the EDNOS diagnosis.
Assessment
There are several assessment instruments that are used in the diagnosis of BED and other eating disordered behaviors. In this section, the most commonly used instruments will be described. Many of these instruments are used for diagnosing the full spectrum of eating disordered behaviors. Based on the criteria changes in the DSM-5, it is possible that some minor changes will need to be made to these instruments as well as to the scoring criteria in determining an eating disorder diagnosis. If such changes are made, new validity and reliability testing will have to be performed on the instruments.
The Eating Disorder Examination (EDE; Cooper & Fairburn, 1987) is a semistructured interview that is used for assessing eating disorders, including BED (i.e., Ahrberg, Trojca, Nasrawi, & Vocks, 2011; Ansell, Grilo, & White, 2012; Barnes, Masheb, White, & Grilo, 2011; Fairburn & Cooper, 2011). The EDE provides a comprehensive profile of psychopathology based on four subscales: restraint (i.e., attempts to avoid certain foods), eating concern (i.e., concern about being seen while eating), shape concern (i.e., importance of body shape in self-evaluation), and weight concern (i.e., dissatisfaction with body weight). A global score is also provided to assess overall eating psychopathology. The EDE also assesses overeating (binging) and the use of extreme methods to control weight (purging), two key aspects of eating disorders. Body mass index (BMI) is also calculated as part of the EDE based on the following formula: weight/height2.
The Eating Disorder Examination Questionnaire (EDE-Q; Fairburn & Beglin, 1994) is a self-report version of the EDE interview. It focuses on the 28 days prior to completing the questionnaire, and assesses eating disorder psychopathology that involves loss of control, including objective binges (eating an unusually large amount of food while experiencing a loss of control over eating) and subjective binges (eating amounts of food not considered objectively large still while experiencing a loss of control over eating). The EDE-Q generates four subscales (dietary constraint, eating concerns, weight concerns, and shape concerns), along with a global score reflecting overall eating disorder psychopathology. It has been used in the assessment of BED (i.e., Ahrberg et al., 2011; Ansell et al., 2012; Barnes et al., 2011).
The Eating Attitudes Test (EAT-40; Garner & Garfinkel, 1979) contains 40 items, including eating disordered symptoms and behaviors, and provides an index of eating disorder severity. The scores range from 0 to 120, with higher scores indicating more disturbed eating behaviors. The EAT has been used in the assessment of BED (i.e., Stice, Schupak-Neuberg, Shaw, & Stein, 1994).
The Eating Disorders Inventory-2 (EDI-2; Garner, 1991) is a 91-item self-report questionnaire that assesses cognitive and behavioral characteristics typical for individuals with eating disorders. The original Eating Disorders Inventory (EDI; Garner, Olmsted, & Polivy, 1983) contained 64 items that covered eight subscales: drive for thinness, bulimia, body dissatisfaction, ineffectiveness, perfectionism, interpersonal distrust, interoceptive awareness, and maturity fears. The EDI-2 added 27 new items that are grouped into three additional subscales: asceticism, impulse regulation, and social insecurity. The EDI has been used in the assessment of BED (i.e., Rockert, Kaplan, & Olmsted, 2007).
The Bulimic Investigatory Test Edinburgh (BITE; Henderson & Freeman, 1987) contains 33 items that measure the presence and severity of bulimic symptoms. The BITE includes two subscales: the symptomatology scale (30 items) and the severity scale (3 items), and has been used in the assessment of BED (Kiziltan, Karabudak, Unver, Sezgin, & Unal, 2005; Orlandi, Mannucci, & Cuzzolaro, 2005).
The Binge Eating Scale (BES; Gormally, Black, Daston, & Rardin, 1982) is a 16-item questionnaire, with eight questions describing the behavioral manifestations of binge eating and eight questions describing the thoughts and feelings associated with binge eating. The BES has been used in the assessment of BED (i.e., Carano et al., 2006; Clyne, Latner, Gleaves, & Blampied, 2010; Danner, Ouwehand, van Haastert, Hornsveld, & de Ridder, 2011).
Other assessment instruments used in the diagnosis and assessment of BED and other eating disorders include Impact of Weight on Quality of Life Questionnaire–Lite (IWQOL-Lite; Kolotkin, Crosby, Kosloski, & Williams, 2001), a 31-item, self-report measure that assesses five domains of quality of life, including work, public distress, sexual life, physical function, and self-esteem; Questionnaire on Eating and Weight Patterns (QEWP; Spitzer et al., 1993), a 28-item self-report questionnaire used to measure binge eating and bulimic symptoms; Emotional Eating Scale (EES; Arnow, Kenardy, & Agras, 1995), a 25-item scale designed to measure the intensity of the relationship between an individual’s eating and negative affect; and Eating Disorder in Obesity (EDO; de Man Lapidoth, Ghaderi, Halvarsson-Edlund, & Norring, 2007), a self-report questionnaire based on the DSM-IV diagnostic criteria for BED. Specific body concerns of individuals with BED have been assessed using Body Shape Questionnaire (BSQ; Cooper, Taylor, Cooper, & Fairburn, 1986) and Body Shape Questionnaire–Short Version (BSQ-S; Evans & Dolan, 1993), self-rating scales that estimate an individual’s disturbed perceptions of body shape and weight; and the Body Uneasiness Test (BUT; Probst, Vandereycken, van Coppenolle, & Vanderlinden, 1995), a 20-item self-report questionnaire that measures three areas of body experience, including negative appreciation of body size, lack of familiarity with one’s own body, and general body dissatisfaction.
Comorbidity
Wilfley et al. (2000) looked at 162 clients with BED and found that 77% met the criteria for a least one additional psychiatric disorder, the most common being mood disorders (61%), substance use (33%), and anxiety disorders (29%). They also found that lifetime psychiatric comorbidity was significantly more likely in men (93%) than women (73%), as was substance use disorder (57% of men vs. 28% of women). Hudson et al. (2007) found that 78.9% of individuals who met the DSM-IV criteria for BED met the criteria for at least one other core DSM disorder and concluded that eating disorders are positively related to most of the mood, anxiety, impulse control, and substance use disorders after controlling for age, gender, and ethnicity. In addition, they found BED to be strongly associated with current severe obesity (BMI greater than 40).
Grilo, White, and Masheb (2009) found similar results when they assessed lifetime and current psychiatric disorder comorbidity in 404 clients with BED. They found that 73.8% of the clients had at least one additional lifetime psychiatric disorder and 43.1% had at least one current psychiatric disorder. Mood disorders (54.2%), anxiety disorders (37.1%), and substance use disorders (24.8%) were the most common lifetime disorders, while mood (25%) and anxiety (24.5%) disorders were the most common current disorders. Concurrent substance use disorders were relatively infrequent (2.7%). They also found that men were more likely than women to have lifetime rates of substance use, as well as higher current rates of obsessive-compulsive disorder.
Analysis of comorbidity has been examined, as researchers attempt to validate BED as a separate disorder. Grucza et al. (2007) found that individuals with BED were at increased risk for depression, generalized anxiety disorder, panic attacks, and past suicide attempts. They further determined that individuals who were obese but did not meet the criteria for BED were not at elevated risks for any of these syndromes. Wilfley, Wilson, and Agras (2003) concluded that individuals with BED differed significantly from individuals without an eating disorder, and shared important similarities with, but were still distinct from, individuals with anorexia nervosa and bulimia nervosa. They found BED associated with co-occurring physical conditions and mental disorders, as well as impaired social functioning and lowered quality of life.
Treatment of BED
There has been significant research in the treatment of BED, although results have been somewhat inconsistent. Vocks et al. (2010) compared the mean effects from a total of 38 studies that met their defined inclusion criteria. Results from this meta-analysis include the following: (1) Psychotherapy and structured self-help based on cognitive–behavioral interventions were found to have a large effect in reducing binge eating; (2) Medication, mainly antidepressants, had medium effects in the reduction of binge eating; (3) Uncontrolled studies using weight-loss treatments showed moderate reductions of binge eating and was the only intervention that resulted in a considerable weight reduction; and (4) Combination treatments did not result in higher effects than single treatments. The researchers concluded that cognitive–behavioral psychotherapy and structured self-help should, at this time, be considered the first-line treatment for clients with BED.
Reas and Grilo (2008) conducted a meta-analysis that looked specifically at pharmacotherapy for BED. They concluded that their findings “indicate patients with BED can be conservatively advised that certain pharmacotherapies may enhance the likelihood of remission from binge eating over the short term but that the longer-term effects of pharmacotherapy-only therapy are unknown” (p. 2036). They also suggested that clients be told that while some weight loss may occur, substantial weight loss should not be expected as a result of the pharmacotherapy. They highlighted the need for further research to provide longer term outcome data to determine the durability of various pharmacotherapy treatments for BED.
A systematic review (Brownley, Berkman, Sedway, Lohr, & Bulik, 2007) of randomized controlled trials of BED treatments looked at 26 studies and found moderate evidence to support medication-only, medication plus behavioral therapy, and behavioral interventions for BED, and fair evidence to support self-help interventions. The author’s analysis revealed strong evidence to suggest that BED treatment involving medication are associated with harmful effects, but found no harmful effects for all other types of interventions. In addition, while cognitive–behavioral interventions have shown the most promise in the treatment of BED, they point out that “Evidence is growing that self-help is efficacious in decreasing binge days, binge-eating episodes, and psychological features associated with BED and in promoting abstinence from binge eating” (p. 345). Sysko and Walsh (2008) looked at published studies that looked specifically at the efficacy of self-help programs in the treatment of bulimia nervosa and BED, and concluded that self-help interventions appear to provide more symptom reduction than being waitlisted for treatment (Grilo & Masheb, 2005; Loeb, Wilson, Gilbert, & Labouvie, 2000). However, when compared to other treatments, the evidence in support of self-help interventions is inconclusive.
Based on the evidence offered by Vocks et al. (2010), suggesting that pharmacological treatments alone were not as effective as psychological treatments for BED, Iacovino, Gredysa, Altman, and Wilfley (2012) conducted a review of the psychological-only treatments for BED, including the following: individual and group format cognitive–behavioral therapy, guided self-help cognitive–behavioral therapy, interpersonal psychotherapy, dialectical behavior therapy, and behavioral weight loss. They offer the rationale for utilizing these various interventions, as well as providing empirical support for the intervention, focusing on the reduction of binge eating, abstinence from binge eating, and posttreatment and long-term follow-up outcomes. Iacovino et al. (2012) make the following suggestions regarding the psychological treatment of BED: (1) Cognitive behavioral treatment remains the most studied and the most established psychological treatment for BED; (2) It remains unclear which, if any, pharmacological treatment may enhance the long-term effectiveness of cognitive–behavioral treatment; (3) Guided self-help cognitive–behavioral treatment can be disseminated to clients more easily and at a lower cost than other psychological treatments, and research suggests that it is an effective treatment for BED, particularly compared with no treatment; (4) Interpersonal psychotherapy has shown comparable long-term outcomes to cognitive–behavioral treatment, and may be a more appropriate first-line treatment for clients with more severe eating pathology and lower self-esteem; (5) Behavioral weight-loss treatment is not as effective as specialized treatment for BED in reducing binge eating in the short or long term; and (6) Dialectical behavioral treatment has shown some promise in the treatment of BED, but more research is needed to examine its long-term efficacy compared to other specialized treatments for BED.
Future Research Questions
Diagnostic Criteria
A question, which relates to the diagnostic criteria for both BED and bulimia nervosa, that continues to be debated in the eating disorder field is the definition of a binge. As you can see in Table 1, the definition of binge includes eating an amount of food that is larger than most people would eat. Researchers have argued that loss of control over eating, rather than the amount of food, should be emphasized when defining a binge. Latner and Clyne argue that future discussions of BED diagnostic criteria (as well as the criteria for bulimia nervosa, which also includes binge eating) should consider expanding the definition of a binge eating episode to include “loss of control over eating while consuming small or moderate amounts of food” (p. 10). They also call for researchers to consider the validity of requiring at least three of the five criteria associated with the binge eating episodes be met prior to BED diagnosis. Further research may indicate a different optimal number of met criteria for a BED diagnosis. Finally, they point out that shape and weight overvaluation is currently a diagnostic criterion for bulimia nervosa but not BED. They suggest, along with other researchers (i.e., Ahrberg et al., 2011), that this criterion be considered for future definitions of BED.
Other researchers continue to examine the differences and similarities between obesity with BED and obesity without BED, as well as the differences and similarities between normal weight individuals with BED versus individuals diagnosed with bulimia nervosa, non-purging type. Inappropriate compensatory behaviors that are considered non-purging in the diagnostic criteria for bulimia nervosa include fasting and excessive exercise. Some researchers have concluded that normal weight individuals with BED may be closer to the DSM-IV non-purging bulimia nervosa than to BED with obesity in terms of prognosis and clinical severity (Danner et al., 2011). Carrard, van der Linden, and Golay (2012) suggest that “it may be wise to aggregate normal-weight BED and bulimia nervosa-non purging type in the same category” (p. 353).
Davis et al. (2008) did not find psychological differences between obese individuals who binge eat versus those who do not; however, they do suggest a possible biological difference that may distinguish these two groups. They propose a future research goal should be “to examine neuropsychological differences between BED and nonbinging obese adults to investigate more thoroughly whether binge eating is a phenomenon sufficiently different from other forms of overeating to warrant the label of ‘disorder’” (p. 249). Carrard et al. (2012) state:
Studies comparing normal-weight BED individuals, obese BED individuals, bulimia nervosa—non purging and bulimia nervosa—purging individuals with interviews are needed to have a clearer view of the various reasons why BED is correlated with obesity or not depending on the individuals. (p. 353)
Prevalence Estimates
With regard to prevalence research, Brownley, Berkman, Sedway, Lohr, and Bulik (2007) point out that research priorities in the area of BED should include determining prevalence in adolescents, as well as looking at specific issues relating to gay, lesbian, transsexual, and transgender individuals.
Researchers will most likely continue to look at the high prevalence of the EDNOS diagnosis, with the goal of reducing reliance on and the prevalence of the EDNOS diagnosis. Fairburn and Cooper (2011), two of the leading authorities in the field of eating disorders, already have their sights set on the DSM-6. They argue that experts in the field must continue to work toward a classification system for eating disorders that matches the clinical realities of the population of individuals who suffer with eating disorders.
Treatment of BED
Brownley et al. (2007) found that men, children, and adolescents were all undersampled in psychotherapy, self-help, and other behavioral trials of BED treatment. In the studies that reported race or ethnicity, minority participation was approximately 7%, but results were never analyzed by race or ethnic group. Therefore, in their systematic review, they found no data regarding differential efficacy based on gender, age, race, or ethnicity. Issues related to sexual orientation is also noticeably absent in the BED literature.
Tanofsky-Kraff et al. (2007) looked at children and adolescents who binge eat, and found an association with excess weight gain and increased risk of developing BED. Based on this research, Iacovino et al. (2012) conclude that the early identification and treatment of children who suffer from binge eating and are at risk of developing BED is critical. Given the additional fact that the number of overweight children has increased significantly in recent years, the problem of overweight and obesity in children and adolescents is becoming a major public health concern (Ogden et al., 2006).
Brownley et al. (2007) suggest that medication trials treating individuals with BED should focus on achieving abstinence from binge eating rather than reducing the frequency. In addition to abstinence from binge eating, they suggest that studies should state explicitly whether weight loss is a targeted outcome. Based on their research, they conclude that interventions that target motivation to change and encourage retention in treatment “will be instrumental in moving the field forward” (p. 346). The use of motivational interviewing has been used in the treatment of eating disorders, but additional research is needed, particularly in the treatment of BED. Knowles, Anokhina, and Serpell (2013) point out that:
Eating disorder treatments are plagued by poor engagement and high drop-out. People who disengage from eating disorder treatment appear poorly motivated to change, and may benefit from adaptations of Motivational Interviewing. (p. 97)
Finally, the need for longer term research studies looking at the treatment of BED is clear. Reas and Grilo (2008) state:
Implications for research include the need for additional large studies and longer studies with more comprehensive assessment protocols. In particular, there is a pressing need for RCTs [Randomized Controlled Trials] of medications to include follow-up periods and to provide longer-term outcome data to address questions regarding the durability or maintenance of clinical effects. (p. 2037)
Conclusion
There is already a substantial body of literature available to social workers and other human service workers regarding the assessment and treatment of BED. As BED is introduced as a distinct eating disorder in the DSM-5, it is clear there are still some areas where further research needs to be conducted, particularly in the differentiation between BED and other disordered eating pathologies, and the treatment of clients with BED, both with and without concurrent obesity. It will be exciting to see the progress the field makes over the coming decade as researchers attempt to solve these and other issues regarding the treatment of eating disorders.
Footnotes
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.