BED7787 - SECTION 2: CAUSES AND RISK FACTORS FOR BED
As we have noted, at present no one knows the exact mechanisms or causes underlying BED. There is, to date, an insufficient amount of definitive research, and correspondingly limited knowledge about the exact causal elements responsible for BED. (34) There is no compelling evidence that a single isolated factor causes an eating disorder. Rather, researchers and clinicians (at least, those who propose that BED actually exists as a separate disorder) believe that this disorder may be more like a puzzle, with many parts working together in a layered manner to create the problem.
As in the case of other eating disorders, it is probable that BED may be attributed to some combination of genetic, physiological, nutritional, psychological, familial and cultural components. The research is most clear that both biological and psychosocial factors are implicated in the development of pathology. Vulnerability, genetics, and culture and nurture factors all seem to contribute. However, how these factors operate with each other and with other factors is still somewhat speculative.
This means that BED is a complex and multifaceted disease (as we will see under the topic of treatment). This means that not only is the disorder difficult to assess, evaluate and treat in an adequately thorough manner, but also that highly complex interventions are required to treat it.
As an introduction to some of the complexities, we will briefly touch upon the impact and importance of some of these etiological factors here. It seems that the main factors identified for BED are adverse childhood experiences, parental depression, and enduring negative comments about shape and weight and eating. (34) At least one study noted that BED patients report worse family of origin experiences than patients with other kinds of eating disorders. (54)
BED patients seem to report more childhood obesity and more exposure to negative comments about their weight than healthy controls. In comparison to BN, however, these risk factors for BED are weaker and more circumscribed. (34)
Japanese researchers have done intricate work on genetics studying the dopaminergic system. This is the neurotransmitter system that is associated with feelings of pleasure and reward, and with positive, hedonic processes related to food, sexual activity and certain substances. Since these researchers recognize that patients with binge eating behavior may have substance abuse problems, too, they also studied substance abuse.
90 female Japanese patients with eating disorders diagnosed using DSM-IV were compared with 115 healthy female controls. Genomic DNA was extracted from whole blood, and standard polymerase chain reaction testing was performed. In the group whose members had an eating disorder with binge-eating behavior, the frequency of a short allele (a specific kind of genetic marker) was significantly higher compared with the control group.
The researchers concluded that it is plausible that there is an association between the DAT1 VNTR genetic marker and binge-eating behavior, and that this indicates that dysregulation of dopamine reuptake may act as a common pathophysiologic mechanism in eating disorders with binge-eating behavior and in disorders related to substance use. (100 ) This study seems to give a biological and genetic base to binge eating disorder and BN, because both of the disorders have binge eating as part of their core make up.
Another study, published in the March 6, 2006 reported that researchers found that family members of obese individuals with BED were twice as likely to suffer from the condition as were obese individuals who did not have a family history of binge eating. (58)
The study found a lifetime diagnosis of BED in 87 of the 431 relatives of subjects with BED and 44 of the 457 relatives of subjects without the disorder. The study also found that relatives of subjects with BED were 2.5 times more likely to be severely obese than relatives of subjects without BED.
Dr. James I. Hudson, MD, ScD, the lead author of the article and director of the Biological Psychiatry Laboratory at McLean Hospital, said:
"The current epidemic of obesity has many causes. This study says that there may be a psychobiological cause for obesity, one that is related to impulsive binge eating."
For decades researches have observed that eating disorders run in families. For many years, clinicians have heard from their patients that mothers, sisters or aunts eat in a way that demonstrate disordered eating or a disturbed body image. Formal family studies have shown that relatives of individuals with eating disorders are at greater risk for developing eating disorders themselves. (62)
In fact, individuals with a mother or sister who has suffered from anorexia are twelve times more likely than people without a family history of anorexia to develop AN. In addition, these same family members have a four times greater risk for developing bulimia nervosa. (62)
(Please note: this correlation does not rule out the possibility that eating disorders may also be transmitted to the next generations through nurture, in addition to nature. What percentage of the increased risk of eating disorders can be attributed to parenting and social environment, as opposed to genetics, has not been fully determined.)
Studies of twins have also been surprisingly consistent in showing a substantial genetic contribution to anorexia nervosa and bulimia nervosa. (62) However, these researchers go on to note that even with a predisposing genetic make up, patients might still never develop anorexia nervosa if they did not live in a culture which champions rail-thin supermodels and emphasizes dieting and thinness.
The contribution of genetics to BED is less clear. There have been fewer studies on BED than on BN and AN, and the jury is still out on this topic.
Additionally, we live in a world with 32oz soft drinks and hamburgers that by themselves contain enough calories to meet the caloric needs of a regular active male for a full day. And these jumbo portions are made available at almost every street intersection – and marketed continuously in a variety of media.
Researchers concluded that weight is more strongly inherited than nearly any other condition, including mental illness, breast cancer or heart disease.
Source: Genes Take Charge, and Diets Fall by the Wayside By GINA KOLATA , New York Times, Health May 8th, 2007
At least some research has concluded that BED is a familial disorder. This research has also concluded that the factors involved in making BED a disorder that runs in families are distinct - at least in part - from other familial factors for obesity. (59) Some reports have spoken to an increased rate of psychiatric history in the families of patients who suffer from BED. (12) However, to date there is no study that firmly establishes the exact risk factors.
However, studies of eating disordered behaviors in young girls has shed some light on how eating problems start to develop in childhood. At least one study demonstrated that there are individual - as well familial and environmental - factors that interact in the way children learn how to regulate themselves and their appetites in relationship to food. (13)
This study demonstrated that parental pressure to belong to the "clean plate club” or parental pressure to limit access to snacks was associated with increased consumption of the forbidden foods, even when not hungry. These girls also reported negative emotions. (13)
As a clinician one has to wonder if BED adult patients (who unlike bulimic patients seem not to restrain their overall food intake prior to bingeing) may have had their intake controlled when they were young. Because rates of pediatric obesity seem to be increasing (86), it seems pertinent and important to have further studies to understand the psychology and pathogenesis of BED in children.
Some studies, however, have shown that binge eating - defined as loss of control around food and as a large amount of food eaten - is more common in girls than in boys. (19)
Studies done in girls have shed light on the fact that eating is a very complicated behavior in human beings. There are individual factors and differences concerning eating, as well as environmental factors. Both of these interact with each other, affecting children’s ability to self-regulate. (13)
Furthermore, differences in individual taste, preferences in food, attitudes about nutrition, and feelings about food and weight are influenced by social factors. (44) However, the influence of the family is probably more important, since this is where individuals first learn about their relationship to food and eating. (9) It is also within the family where disturbed patters of eating are unfortunately learned. (107)
In fact, families with eating disorders appear to share some common factors. Girls in families with eating disorders frequently report that they have no support from their fathers. (99) Patients who suffer from BN report that their mothers are not nurturing. (119) Those with AN report affectionless fathers and over controlling mothers. (69)
Additionally, some research suggests that mothers and fathers may have different styles of interacting when it comes to food and eating, therefore intervention programming should target parent adolescent relationship. (5)
42% of 1st-3rd grade girls want to be thinner.
Source: National Institute of Mental Health (Citing Collins, M.E. (1991). Body figure perceptions and preferences among pre-adolescent children. International Journal of Eating Disorders)
Physical and Sexual Abuse:
Some authors have hypothesized that BED may be one of the ways in which some patients might cope with the reality of childhood abuse. (110) One particular study suggests an association between childhood sexual abuse and BED (110), and it is also consistent with others that had the same findings. (34) (124)
On the other hand, at least one study reported that the rates of sexual abuse among patients with BED was no higher that the rates in the population at large. (40)
It is also important to look at ethnic differences when assessing sexual abuse and the risk of mental disorders. The impact of sexual abuse on mental disorders needs to be estimated and viewed in the context of the ethnic and cultural group of the individual being assessed. (135)
Apparently, for black women, childhood sexual abuse may be a specific factor for BED. The rate of sexual abuse for black women is considerably higher (66.7%) than in a population of psychiatric comparison (23.8%). (110)
Some researchers found out that depression and physical abuse were significantly associated, and went hand in hand in both black and white women. (96) Apparently, the rates of physical abuse endured by black and white women suffering from BED were very high. The abuse was also severe. (110)
Bullying (and physical abuse too) seem to be a factor in the development of BED, according to at least one study. Being bullied by peers was associated with BED in both black and white women. (110)
However, bullying seems to be an unspecific factor. The two factors - bullying and physical abuse - were associated with the development of mental disorders, in general. They were not uniquely paired to the development of BED. (110)
While bullying is more usually viewed as being a male phenomenon, in recent years researchers have also turned their attention to the effects of bullying among females, as well. According to clinicians and parents, in recent years bullying has been an issue that has apparently been more seen between girls, especially in middle and high school.
Typically, women bully not through physical force, but through relational aggression (RA). (101) Bullying occurs when females use the relationship they have with each other to hurt others by including them, leaving them out, forming cliques or ignoring and mistreating their ‘friends”. (21)
Cornell studies find women in food-insecure homes engage in more binge eating and eat fewer fruits and vegetables. Cornell researchers said that women in food-insecure households eat particularly less fruit, salads, carrots and other vegetables than other women but consume a similar number of calories. Food -insecure women may be at higher risk for obesity because they overeat at times when adequate foods become available to the household.
FOR RELEASE: June 18, 1997
Discrimination seemed to be a risk factor for BED among black women. White women reported much less discrimination, but surprisingly reported more instances where they felt discriminated against than did healthy comparison or psychiatric comparison groups. (110)
Aside from genetic reasons for BED, there are other theories that try to explain the maintenance of the behavior of binge eating in patients. These theories, in general, revolve around the idea of patient affect. At least one of the reasons for this is that popular models that try to explain binge eating disorder are models derived from what clinicians and researchers know from other eating disorders.
One important study summarized that binge eaters do appear to eat due to negative mood. (106) Participants in this study entered in small handheld computers their mood and intake and place where they most binged. The study concluded that negative mood was the main reason for binge eating.
However, the paradox it uncovered is that mood after a binge was worse than before the binge. Therefore, if the binge was a strategy to stave off more aversive affective conditions, the bingeing strategy failed the patient.
However, a more psychodynamically inclined health professional could argue that that is the fate of symptoms in general. They do not totally achieve what they set out to do.
Another theory to explain binge eating is attribution theory. In this theory, the binge eating would be the depository of all the bad feeling that the patient has. The binge eating problem carries the blame for the patient’s problems while the patient need not face the rest of his or her life. In this sense, the binge eater is trying to mask, with the binge, deeper problems. (106)
The study also concludes that negative feelings are related to whether overeating feels out of control for BED individuals. Interestingly, women with BED also seem to binge when they feel only mildly negative feelings. (61) It also seems that individuals suffering from BED may be less susceptible to internal cues of hunger - which leads them to eat more in response to distress. Non-binge eaters eat less in response to distress. (92)
Escape From Self-Awareness Theory:
At least one author in the field proposes that binge eating is motivated by a desire to escape from self-awareness. This theory proposes that binge eaters suffer from high standards and expectations. Binge eaters, these authors maintain, are acutely sensitive to what they perceive to be others’ demands of them. When binge eaters fall short of what they believe the correct standard for their actions or appearance might be, they develop negative high self-awareness and a fault-finding view of their own self.
Patients who binges eat become very concerned with how others view them and as how they are perceived. These aversive self-perceptions are accompanied by emotional distress, which often includes anxiety and depression. (52)
To escape from this unpleasant state, binge eaters attempt cognitive response of narrowing attention to the immediate stimulus environment and avoiding broadly meaningful thought. This narrowing of attention disengages normal inhibitions against eating and allows for an uncritical acceptance of irrational beliefs and thoughts. The escape model is an interesting theory because it is capable of integrating much of the available evidence about binge eating. (52)
Paxton and Diggens's 1997 study tested both components of Heatherton and Baumeister's model. (87) However, this model would need to be elaborated on further to be applied to BED per se. Although Paxton and Diggens's study examined a sample that was comprised of restrained eaters - who also engaged in binge eating - the results of the study are still interesting to take into account. Paxton and Diggens concluded that restrained eaters who binge eat exhibit higher levels of negative self-awareness. (87)
In the opinion of this author, the escape model is an interesting theory because it allows the integration of the patient’s lack of inhibition about eating, even in absence of physical hunger. This lack of inhibition may be due to the narrowing of the patient’s attention to immediate stimulus and also to his/her emotional overload.
However, it is striking that while this model is well-known and cited in the literature, its direct applicability to binge eating has been tested only by very few studies. (10) In the study An Application of Escape Theory to Binge Eating, the inclusion criterion for the participants was a self definition of a dieter. The sample again was composed of college students and other participants recruited from community newspapers. Participants did not necessarily meet the diagnosis for BED. The majority were occasional bingers.
The study concluded that the application of the Escape Theory to Binge Eating was a good fit for the 129 non-clinical sample women. In other words, negative affect predicted levels of avoidant coping which in turn heralded levels of binge eating. (10)
There are clinical implications of whether any or all of these theories can be validated. If BED is used as a mechanism to escape self-awareness, then approaches can be utilized to reduce the stress and pain of self-awareness, making binge eating behaviors less necessary. This begins to inform the therapeutic choices of the clinician.
In summation, there is at present no widely accepted, unifying theory concerning what causes BED. What research and clinical practice suggest is that patients with BED tend to have a family history in which some degree of family dysfunction was present, causing a degree of persistent emotional distress, often including depression and poor self-image, as well as some difficulties developing effective impulse control and emotional self-regulation skills.
Additionally, BED patients appear to have learned to utilize eating as a method of handling their emotional discomfort during periods of distress, precipitating eating binges. Simultaneously, however, many BED patients also appear to generate additional sources of distress through their over-eating. The over-eating can lead to a sense of losing control of themselves and a drop in self-esteem. This creates a self-propagating system of bingeing, heightened emotional distress from the overeating, and further bingeing.
The origins of the emotional distress in this system may be complicated. The family of origin may give a variety of messages about weight and eating to the patient, some of which may heighten the emotional distress and damage the patient's self-image. More certain is the message that the larger culture is likely to give: thinness and self-control are valued; obesity and self-control problems are scorned. The next section of this course touches upon some of the cultural elements that may contribute to this self-propagating system.
Later, this course will integrate the implications of this theoretical perspective on the origins of BED, and see what can be developed in terms of successful intervention.
91% of women recently surveyed on a college campus had attempted to control their weight through dieting; 22% dieted "often" or "always".
Source: National Institute of Mental Health (Citing Shisslak, C.M., Crago, M., & Estes, L.S. (1995). The spectrum of eating disturbances. International Journal of Eating Disorders, 18 (3))