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Researchers suspect that many more people suffer from binge-eating disorder (BED) than from anorexia and bulimia, but that cultural insensitivity and the lack of insurance coverage for treatment means that the disorder remains an invisible killer. In “The Binge and the Brain,” this month’s Cerebrum article, our authors lean on their research and clinical experience to discuss the state of BED neurobiological underpinnings and advances in treatment that can come from behavioral interventions that target and better understand mechanisms in the brain.
What has happened in recent years to help us better understand the neurobiology of binge-eating disorder (BED)?
Cusack: The addition of BED in the DSM-5 (the Diagnostic and Statistical Manual of Mental Disorders) has definitely legitimized BED and, as recent research shows, there may be a higher prevalence rate of BED than with either bulimia or anorexia. So it’s really important that we better understand BED. Imaging studies, particularly using fMRI, have really advanced the research.
Ely: But we need to also understand that the neurobiology research into BED is still in its infancy. Given that eating disorders were previously or traditionally considered to be psychosocial disorders, advances in the last ten years show that BED is indeed based in neurobiology. No specific gene has yet been linked to any of the eating disorders in particular and, to my knowledge, there has been no large genome-wide association study that has looked at BED in particular.
How does one know if they tend to often over eat or suffer from BED?
Cusack: Negative health consequences or enduring a high degree of guilt and shame to the point where it’s interfering with your ability to function or have positive relationships will tell you. Thanksgiving, for example, seems to be a nationally endorsed day of binge eating. But very few of us after Thanksgiving are at the point where we can’t get out of bed and do something productive with our day. If that was the case, Black Friday wouldn’t be a thing. With BED, you know it’s more serious if you can’t get out of bed after Thanksgiving or other days during the year.
Ely: The ‘loss of control’ piece is what differentiates any episode of overeating from an episode of binge eating: a feeling of not being able to stop once you’ve started; not being able to avoid eating in the first place, or the avoidance of eating when you’re around other people.
Does genetics play a part in making people at risk for BED?
Cusack: There are some personality and temperament traits that are inherited; traits such as perfectionism, cognitive rigidity, harm avoidance (a mix of anxiety and inhibition), and a tendency towards depression. We know that many of those traits are passed down in families and are fairly stable across time, and were there prior to the eating disorder.
Ely: At the same time, some of those traits can help people become successful, such as perfectionism and cognitive rigidity, when those traits are applied to constructive domains in a moderate way. BED very much depends on environmental cues and lifestyle.
What are the neurobiological differences between people who suffer from anorexia and bulimia vs. BED?
Cusack: In eating disorders generally, the brain has difficulty in distinguishing between reward and punishment. Eating disorders tend to activate the brain to wins and losses in similar ways, whereas the brains of healthy people tend to activate more to reward and less to punishment. We are not seeing that in eating disorders. So difficulty evaluating reward is common among eating disorders.
Inhibitory control seems to be a distinguishing characteristic. In anorexia, we see elevated activation in cognitive control centers and in bulimia and BED it’s much more dysregulated.
Ely: We also see a differentiation between in anorexia and BED in their ability to delay reward. So if you asked someone with anorexia if they wanted $20 today or $23 in two months, many people with anorexia would want the $23 in two months and people with BED (which is more in line with normative controls) would say they want the $20 today. It can be dependent on education, but we see a difference in ability to delay gratification.
Is there a taste cortex in the brain and does the brain respond differently to different types of food or tastes?
Cusack: Yes, it’s primarily in brain regions called the insula and the frontal operculum. Both regions respond to the sensory aspects of taste as well as integrating taste sensations with your body states and motivational drive. Research tends to focus on sweet tastes, especially in regard to eating disorders. To my knowledge, there hasn’t been any neurobiological research relating to bitter or sour tastes.
Ely: Clinically, we have patients with BED who prefer certain tastes to others. At certain times, they lean toward sweet. But we also get patients who prefer sour or salty tastes. Hopefully, that’s an area that research can move into.
Can people control BED without professional help?
Cusack: Unlike most other addictions or substance-abuse disorders, we can’t ask people with BED to totally abstain from the thing they’re unable to manage. Even if someone binges on particular foods, we can’t ask them to completely stop eating those foods. I’m sure that there are people who have had binge episodes and their episodes have lessened when some of the stress has disappeared from their lives. But seeking professional help is really critical to help learn skills and tools—especially if the problem continues to affect their health and get in the way of their life. There is Cognitive Behavioral Treatment (CBT) therapy called Guided Self Help, which is often done in conjunction with professional therapists or psychologists. It is a largely at-home, an 8 to 12-session structured treatment.
Ely: It’s like any other psychiatric disorder in the sense that there are gradients of how severe the disorder can be. Ideally, you’re going to want to intervene with professionals before something becomes severe. So I would argue that if you’re experiencing binge eating on a regular basis, however infrequent, wouldn’t be better to learn more adaptive ways to cope?
How does stress and other emotions relate to BED?
Cusack: The reason CBT is the gold standard for treatment for BED is because there are a lot more things than stress and anxiety that help activate binge eating. It could be an uncomfortable thought or emotion or feelings of loneliness. For example, someone cancels plans and then you’re home alone feeling vulnerable and bored. There is also shame, grief, anger, frustration, jealousy, envy—the list goes on and on. Any sort of life event or thought can prompt discomfort that lead to binge eating, especially if you have the neurobiological underpinnings and that coping strategy.
Ely: A common feature of BED, anorexia, and bulimia is an inability to tolerate discomfort and distress. Binging or purging is a means to avoid or ameliorate that distress. Over time, episodes start earlier, so that the distress is felt less intensely, to the point that even a small amount of distress can lead to a binge episode.
Do you sense that BED is an undertreated problem?
Cusack: Most definitely. Clinically, we treat a much higher number of people who suffer from bulimia and anorexia than we do with BED. And we are finding out that the likelihood of BED is higher.
Ely: Because the physical presentation of BED is usually obesity, most people typically end up in treatment through their primary care physicians. If he or she is only giving you feedback about behavioral weight loss, that is not going to be effective in treating BED. There is also a lot of shame involved in this disorder, so people are reluctant to talk about it.
Cusack: There is a lot of activism around things such as schizophrenia and depression because the cultural response is that there isn’t a choice. But that’s not the perception with BED, even though we now know that there are neurobiological underpinnings that cause people to binge. So there’s this cultural shame that says that one should be able to limit or control their eating.
Is BED treatment insurable?
Cusack: Sometimes. That was one big benefit of inclusion in the DSM. But even when it’s covered, the length of time allowed for treatment is too short. That’s sad, because we know that if people are able to get the right amount of treatment, there is a very low rate of return-to-treatment, unlike other eating disorders. Which suggests that treatment is more effective.
Ely: Unlike anorexia, it’s not considered to be as severe or medically dangerous and insurance companies are less likely to cover the level of necessary treatment.
What are some of the treatment strategies?
Cusack: We look at core beliefs in the CBT tradition to help people realize the specific thoughts that trigger their eating disorder so that the behavior to binge becomes less powerful. There is also a treatment strategy about learning skills to tolerate distress. We call them Tip Skills, which helps you realize what’s happening in your body physiologically so that you can help your body change the emotional signals that are being sent to the brain. There is also interpersonal effectiveness work; helping people learn how to get though their experience with emotional discomfort.